Publications Heading
Click on the links below to read some of the interesting articles and publications about conservation projects we believe in.
"Crocodiles vs People"
Published in the "Wildlife Australia" Autumn 1998 edition
"Harriet, The Galapagos Tortoise, Disclosing One and a Half Centuries of History"
Published in "Reptilia" March/April 1998
"The Cooperative Conservation of the Fijian Crested Iguana"
By Terri Irwin (Australia Zoo)
"Breeding Behaviour of the Canopy Goanna"
By Kelsey Engle (Australia Zoo)
"The Poorly Known Rusty Monitor Varanus Semiremex: History, Natural History, Captive Breeding and Husbandary"
By Richard Jackson (Australia Zoo)(Herpetofauna 35(1): 15-24.)

"Cocodrilos de la Laguna del Carpintero"
Newspaper Article from El Diario de Tampico 13 February 2s003



Text by Steve and Terri Irwin and Barry and Shelley Lyon
All photographs courtesy of
Steve and Terri Irwin

Two species of crocodiles, the Freshwater Crocodile (Crocodylys johnstoni) and the Saltwater Crocodile (C. porosus) occur in Australia. Only ‘salties’, which can grow very large, have been responsible for fatal attacks on people.

In Australia, the ‘saltie’ ranges across the north and east between Broome, Western Australia and Maryborough, Queensland. Notwithstanding its common name, this crocodile lives in fresh, brackish and salt waters. It can be encountered in the open ocean, near the shore and in and near estuaries, freshwater rivers and the swamps and lagoons associated with them, sometimes hundreds of kilometers from the coast.

Skins from salties, especially big ones, make excellent, highly prized leather. Demand for skins (for use in shoes, belts, suitcases, briefcases and handbags), supported a significant crocodile-harvesting industry in northern Australia between the end of World War II and the 1960s. Two factors led to the industry's decline and final cessation.
Firstly, saltwater crocodiles progressively became more difficult to find as populations declined, due to relentless, skilled hunting. Secondly, by the late 1960s-early 1970s, conservationists and governments were concerned that the species might become extinct in Australia. At a time when the industry had almost literally ‘killed the goose that laid the golden egg’, federal and state governments protected crocodiles by legislation.

Saltwater Crocodile
Saltwater Crocodile

In Queensland, despite such protection since 1974, the Saltwater Crocodile remains on the threatened species list as ‘vulnerable’. Since the 1970s, populations of salties have grown. Big crocodiles (usually male) are once again fairly common. They, and smaller crocodiles, have been encountered with increasing frequency, not only by adventurers in remote areas, but also by people in and near cities and towns. Some of these encounters have resulted in fatalities.

This problem can be reduced, possibly even eliminated, by instilling cautious, commonsense attitudes in people whose activities place them in potential contact with salties.
However, despite wide community awareness of, and response to, warning signs and educational information provided by fauna authorities, occasionally crocodiles continue to pose a threat to people.

One response to this problem has been devised by the Department of Environment in Queensland. The East Coast Crocodile Management Program was established in 1985 to deal with rogue or nuisance crocodiles. Under this program, potentially dangerous animals are captured and transferred to crocodile farms, wildlife institutions or back to the wild in areas remote from settlement. This strategy is costly and sometimes risky, but seems to work. Certainly the problem is alleviated — at least in the short term. However, removing a crocodile from its domain does not mean an area completely safe, merely that it is safer than it was.

Where there are healthy populations, salties usually live in communities. A permanent, deep 1 km long lagoon, where there is a constant food supply, could easily support between six and ten crocodiles. Such a community would have a well-defined ‘social ladder’. On the top rung would be a dominant, large male; next would be two or three breeding females; and then, at the bottom of the ladder would be varying numbers of immature crocodiles. Depending on the availability of food, the lagoon might also support another two or three young, sexually mature males. However, the dominant ‘boss’ of the lagoon would always keep these, through intimidation and fights, on the ‘outer’.

Saltwater Crocodile
Saltwater Crocodile

In such a situation, removal of the dominant male might solve a ‘people problem’ temporarily. But, following battles for supremacy, another dominant male will ‘reign’, restore order to the lagoon and may again threaten people. Thus, while removal may eliminate immediate threats to human safety, it is hardly a definitive long-term solution. There are problems too for big crocodiles removed from their habitats. Capture and handling can be harsh, sometimes brutal and adaptation to captivity in what are sometimes far from ideal conditions can be difficult, sometimes impossible.

In Queensland, Saltwater Crocodiles occur most commonly in rivers and lagoons associated with the Gulf of Carpentaria. Populations of salties in eastern waters are, by comparison, low with one exception — Lakefield National Park, on south-eastern Cape York Peninsula. Lakefield protects the largest population of Saltwater Crocodiles in eastern Queensland. The national park of 537,000 ha is one of only five key areas for C. porosus conservation in Queensland.

In 1994, there were many reports about a large saltie at Old Faithful Water hole, a popular fishing and camping area on the Normanby River. The crocodile, estimated to be 4m long, was swimming close to and approaching people fishing in boats and from the high riverbank. Following assessment by park staff, the area was closed to visitors to reduce potential risks to them and the crocodile. (Illegal shooting had been a problem on the park before.) A decision was made not to attempt to move the crocodile, but to trial a new management strategy that might maintain the well-established social structure in the water hole, yet make it safe again for people. Because of the problems associated with relocation of large crocodiles, the experiment involved capture and harassment of the crocodile and its release to the same waterhole. The aim was to instill fear of people (‘people shyness’) in the crocodile so that he would be reluctant to approach them.


With Lakefield’s Ranger-in-Charge, Ron Teece, the crocodile was trapped and ‘educated’ with what appears to be some success. The ‘aversion’ experiment had three main objectives: Instilling ‘people shyness’; maintaining existing social structures in the waterhole; and making it possible to reopen the waterhole to visitors, appropriately educated about his presence.

We arrived at the waterhole on 12 December 1996. A large crocodile, apparently curious, could be seen watching from a distance of about 50m. He continued to watch as a survey dinghy was prepared and as the boat slowly moved upstream.

By two pm that day, the first trap had been erected in a deep, shady location where basking and ambushing sites of crocodiles were located. (The trapping method was developed by Steve and Bob Irwin.) An undulating, melaleuca-lined bank was cleared of foliage and debris, then leveled with shovels to create a large clearing about 2m from the water’s edge for the-nylon mesh trap. The trap was rated at 16 tonnes and was supported by sticks hammered into the ground and hemp twine.

The completed rectangular trap was 5 m x 1.5 m x 0.9 m. The entrance was 60 cm from the water’s edge and was evenly interwoven with rope attached to 100 kg weight bags. The bags were suspended from a trap ring about 7 m up a tree (on a branch estimated to be able to withstand a force of 400 kg) and attached to a steel rod trigger mechanism.

The trap was baited with 40 kg of fresh feral pig and secured by a short rope spliced over the trigger mechanism. Any jerking or pulling of the bait would cause the weight bags to fall, pulling the mouth of the trap closed in a drawstring effect.

Early next day a stocky 2.6 m female was found in the trap. She was easily released and the trap re-set it was surmised that the capture of one of the target crocodiles mates may have made him wary of the trap, so a second trap was set on a mud bank.

Old Faithful Captured
Old Faithful Captured
The next morning ‘Old Faithful’ was in the trap. Within half an hour two top jaw ropes were in place and the crocodile was secured. The mouth of the trap had closed around the base of the crocodile’s tail and cloaca, a common occurrence in trapping animals over 3.6 m. To ensure the crocodile was not injured, he was induced to move
fully into the trap. Once inside, a canvas shelter was erected to keep the crocodile damp and so it could be closely monitored. Old Faithful measured 4.2 m from head to tail
with a head length of 56.5cm.

During the first day of capture, team members circled the water immediately in front of the crocodile in two different dinghies, hoping he would learn to fear noise and people. The crocodile soon became agitated whenever an outboard was started and became even more agitated when approached by a 4WD vehicle. The campsite was in
the animal’s full view, and Steve and Terri Irwin camped very close to the crocodile for eight hours so he was forced to see, hear, smell and sense people close by

"People Power" restrains Old Faithful before his release.

During the night the crocodile was further harassed with spotlights from a dinghy with an outboard motor. Next morning the animal was calm and motionless, but when an outboard motor was started he became distressed and fought to escape. A similar escape attempt occurred when a vehicle approached the camp. These reactions were considered positive signs of stress in response to human activity.

Before his release, a team of eight people straddled and restrained the big crocodile for 15 minutes, while the trap and top jaw ropes were removed. Under the weight and power of the people the crocodile hardly attempted to fight. Such passiveness was a desired response. Then, on the count of three, everyone jumped clear and the crocodile was free. Without hesitating, he walked slowly into the shallow water, swam to the middle of the waterhole with his head above water and then headed straight towards the deepest section. The team was fairly confident ‘Old Faithful’ had responded to the ‘aversion therapy’ and that the animal would remain dominant in his territory.

In February, 1997, Old Faithful Waterhole was reopened to visitors. All three campsites were occupied, but campers did not report any nuisance crocodile. In July, 1997 the waterhole was surveyed again to determine the extent of the crocodile’s ‘people shyness’. Old Faithful could not be found by day or night, even though fresh tracks, slides,
claw marks and basking areas were evident.

During this survey, fishermen at the waterhole reported seeing a big crocodile lurking at the boat ramp. Subsequent examination of the bank where their dinghy was moored revealed a crocodile slide, but matching an animal less than 3 m long! This crocodile had apparently been feeding on fish offal, backbones and carcasses left on the bank.

The waterhole was surveyed again in October 1997. Old Faithful and a female (about 2.5 m long) were first observed sunning themselves on the opposite bank. The animals quickly responded to the approach of the vehicle and slid into the water and submerged. This was judged to be ‘people shyness’.

In subsequent surveys of the waterhole, by Dr Geoff Miller and Dr Mark Read of the Department of Environment, several large crocodiles (more than 2.4 m) were recorded, however, none posed any problem.

This is the second time Steve and Terri Irwin have attempted to deter a declared ‘nuisance’ crocodile from approaching people. Such a strategy was used in May, 1995 at Escott Station, northern Queensland. A 4.2 m saltie, ‘Nobby’, was captured, ‘educated’ and released. Three years after his ‘education’, ‘Nobby’ is still only rarely seen by property managers and staff. It is hoped that a similar ‘people shyness’ will deter Old Faithful from approaching people for some considerable time. It is worth noting that large, old crocodiles in Lakefield National Park, that survived the shooting era, are only rarely sighted by rangers or visitors. These crocodiles (longer than 4 m and more than 24-years-old) appear to have maintained their fear of humans for at least 20 years.

To be sure Old Faithful remains wary of people, the crocodile will have to be observed often, at least biannually and there is no guarantee that he will not again pose a threat. Visitors will have to continue to be vigilant! There is only one track into Old Faithful’s Waterhole. A single sign on this track could educate visitors about potential crocodile sightings, Old Faithful’s history, and the value of crocodiles and their conservation in the national park.

All information so far indicates that Old Faithful and Nobby remain dominant in their territories, but avoid any contact with people. In this method, there may be hope for increasing peaceful co-existence between salties and people.


In undertaking the experiment and preparing this account we recieved help from many colleagues and friends. In particular, we thank Chris Banks, Rick Colebrook, Brian Coulter, Jeanette Covacevich, Greg Craig, Thelma Engle, Doug Johnston, Wes Mannion, Liza Olm, Ron Teece, Tony Tucker, Ian Watt and Suzie zum Felde.

Author profiles:
Steve Irwin has been capturing and relocating crocodiles since the 1970s. He and his wife Terri are the Directors of Australia Zoo which conducts research and study of crocodilians in captivity and in the wild.

Barry Lyon is formerly a district ranger for Southern Cape York with the Queensland Department of Environment. He and his wife Shelley were the Rangers-in-Charge of Lakefield when it was gazetted a National Park in 1979.

This article was published in the "Wildlife Australia" Autumn 1998 edition. "Wildlife Australia" is a publication of the Wildlife Preservation Society of Queensland and the Queensland Museum. The magazine is published as a major environmental initiative and all profits from sales are invested in environmental conservation work. "Wildlife Australia" is produced with the assistance of the Queensland Department of Environment.


The Galapagos Tortoise
Disclosing One and a Half Centuries of History

by Scott Thomson(1), Steve Irwin(2) & Terri Irwin(2)

At the Queensland Reptile Park(now known as Australia Zoo), Beerwah, near the Sunshine Coast of Queensland lives a lone female Galapagos tortoise known as Harriet, she's quite an attractive old girl weighing in at an estimated 180kg, which is quite an impressive size for a female Galapagos tortoise. She spends her time soaking up the Queensland sun and is a major draw card at the Reptile Park. The authors all met each other in 1992 when one of us (ST) decided to attempt to identify all the Galaps in Australia and New Zealand to subspecies by determining their complete histories and using this to tie them to a collection site. We, therefore, owe our successful collaboration on this and a couple of other studies, for example Alligator Snapping Turtles, to Harriet. It is with this in mind that we take the opportunity to write down the history of a tortoise who has plodded her way around the world since at least 1834. Unfortunately, it is not yet possible to prove her story and it is difficult not to get caught up in the excitement of it, but the story we present is the most likely scenario based on the information we have. We will also attempt to reproduce the sequence of events, which has led to the evidence we do have.

Gleaning out Harriet's history
Back in 1992 all we knew about Harriet was her recent history, where she had spent the last 40 odd years. Based on this and some morphometric analysis we felt she was probably a Santa Cruz tortoise (Geochelone nigra proteri) We had no idea where to look for her history and began by following her back from previous owner to previous owner.

Harriet arrived at the Queensland Reptile Park in 1987 from Fleay's Fauna Sanctuary. She already had quite a public life as David Fleay was a prolific writer and she featured prominently in Fleay's books. So where did David Fleay find Harriet? He found her in 1936 at the Brisbane Botanical Gardens and purchased her when they closed their zoo in 1952. David Fleay had very little success in locating Harriet's history but did record that she was here in 1870; we have no idea how David arrived at that date but do have a theory on it which we will discuss later. David did contribute significantly to Harriet's history in other ways, because of David her name is Harriet not Harry, when they realised that he was a she in the late 1950's. We also know where her name came from, she was named after Harry Oakmann, who was the Curator of the Brisbane Botanical Gardens and worked there for over thirty years. But nothing on where she came from.

We were able in time to speak to Harry Oakmann and he introduced us to one of Harriet's former keepers from when she a was at the gardens. Both remember Harriet from as far back as the 1930's but didn't know where she came from, the records from the gardens were searched thoroughly for any evidence and we were able to push the confirmed date back a little further, 1893, the great flood of Brisbane.

The newspapers of the day show people sculling down the main street of Brisbane and for weeks the "Courier Mail", a newspaper in Brisbane, started each edition by thanking the Sydney Morning Herald for printing their papers on their behalf, as their Brisbane office was under some five meters of water. This also spelt the end of the Brisbane Botanical Gardens' records as they were all destroyed in the flood.

At this point we thought the search would be lost to time, we had envisaged reading newspaper after newspaper going backwards in the hope that we could find some mention of her arrival in Australia. We never, thankfully, got around to this, can you imagine trying to find words to the effect of "tortoise arrived" in some 100 years worth of daily newspapers!

The sequence of events that actually uncovered her history were so remarkable that saying that we were a little shocked by it all would be understating the reality and the fact remains that this chain of events is still happening as we speak. On 6 July, 1994 the "Sunday Mail" ran a story on the plight of Lonesome George the last of the Pinta Island tortoises (Geochelone nigra abingdoni) entitled "Lonesome George - the last of his breed", this story had absolutely nothing to do with Harriet but it was the trigger. An old retired historian by the name of Ed Loveday from Mareeba in North Queensland thought he would write a letter to the editor mentioning his recollections of the three, not one, tortoises at the Brisbane Botanical Gardens. We have reproduced his letter in full with this paper (chart 1).



The sad story of "George", headed "Last of his kind" in the "Sunday Mail" (July 6), reminded me there were once three galapagos tortoises living in the old Brisbane botanical gardens. In my time, from about 1922 onwards, there were only two still living. I was told they were brought to Brisbane by Captain Wickham, the Government Resident at Moreton Bay around the middle of last century. Wickham had accompanied Charles Darwin on the "Beagle" on his research voyage around the world and spent some time at the Galapagos islands gathering scientific material for Darwin’s classic work "Origin of the Species." It is quite probable that Wickham took the three specimens from there and later installed them in the Botanical Gardens where I saw them several times. Eventually all died, the last one fairly recently. Sadly, they did not reproduce; I never heard of this anyway. Perhaps they were too old when coming to Brisbane, or were of the same sex or they enjoyed the lush Botanical Gardens conditions and did not bother about that. Certainly they were early residents of Old Brisbane Town. They were very long lived. Perhaps others of your readers could add to this reminiscence.

E.M. Loveday, PO, Mareeba.,

i. Wickham never actually made it to the Galapagos, the crew of the "Beagle" Expedition went their separate ways in South America. See "Voyage of the Beagle"
ii. As mentioned in the main article, the recent large tortoise that died was from another part of Queensland and not a Galap.

So now we had some names of people, some dates, a starting point at last. In the next two weeks the information systems were extensively searched for additional information. Ed Loveday's earliest recollection of the tortoises, he only ever saw two as one died last century, was in 1922 when he visited the gardens frequently with his parents. Upon interviewing him some more information was gained. The last time he remembered seeing two tortoises at the gardens was between 1925 and 1930, i.e. six years before Harry Oakmann or David Fleay ever saw Harriet. I assumed that the other animal died and was probably buried or dumped somewhere.

We were also able to ascertain that the tortoise that Ed had thought died recently was a very old Red-footed tortoise (Geochelone carbonaria) which died around 1986. Out of necessity we re-examined the previous morphological identification and concluded that Harriet could be a santiago tortoise (Geochelone nigra darwini) as females of this population and the Santa Cruz population are virtually indistinguishable.


Charles Darwin and John Clements Wichkham had crept into the picture now and this gave our first real information. If you want to look at animals in history there is only one sure way to obtain accurate and continuous information, attach the animal to a famous person and follow the person through history. Therefore the history of all the people who could have been associated with Harriet was studied; Darwin, Wickham, Gray, Bell, to name a few. But also places, Darwin's home; Wickham's home, Newstead House and the Oxford University which has some of Darwin's specimens. We also found out that some old city records from Brisbane, before the flood, are possibly stored at the John Oxley Library in Brisbane, but to date we haven't had time to look.

In September of 1994 we were all in Brisbane for a meeting of the Taxon Advisory Group and one of us (ST) was actually going to try and visit the John Oxley Library to have a dig. First, however, I went to the Brisbane Museum to look at a few specimens of Australian turtles, what I eventually found there left no time for the John Oxley Library. Patrick Couper, the Collection Manager there, mentioned to me that they actually had a large tortoise and that it was listed as an Aldabran (geochelone gigantea). I lifted the lid it was a fully spirit preserved tortoise, genus Geochelone, but it was on its back and from what I could see, essentially the plastron, I thought it might be a very large Yellow-footed tortoise (Geochelone denticulata) or something. So we went back up to Patrick's office and looked up the records, apparently this tortoise was given to the Museum by the Brisbane Botanical Gardens and was lodged (not necessarily received) in 1941. I am fairly certain I beat Patrick back to the spirit room.

This time we pulled it out of the tub and righted it so that the animal could be viewed properly. The most significant thing we saw was painted on its back:

"Tom Galapagos tortoise Died 1929 Brisbane Botanical Gardens"

A close inspection of the specimen brought an even more startling identification. Morphological identifications of Galapagos tortoises are always dubious but this one, a female, had some features which may give a reasonable identification. This was a small Galap, about 80cm straight carapace length, it was a domed form, and yet if it was one of the Botanical garden animals it had to be fully grown as it was at least 60 years old going by David Fleay’s earliest arrival date. It was a very healthy tortoise in its growth form, nice and symmetrical, no bossing of the scutes, no obvious deformities. This animal would appear to be a San Cristobal Tortoise (Geochelone nigra cathamensis) and by this I mean the extinct one from the south of San Cristobal not the half saddleback form (actually a new subspecies not G.n. cathamensis) from the north of the island that they find there now. The wild population of this subspecies disappeared at the turn of the century, the other population was found in the 1950’s. Most important of all was that the very existence of this specimen verified part of Ed Loveday’s story.

The following day at the Taxon Advisory Group meeting we were actually announcing, for the first time, that we had some information concerning Harriet's history, a rather hasty adit was made about Tom. Since the meeting numerous press releases were made in the hope of obtaining further information from the public, with some success. From all the recent information we were able to deduce how David Fleay arrived at the 1870 date of arrival. We suggest that it was actually the earliest date that he could find first hand evidence that she was actually there. We have first hand evidence going back some 73 years from 1995. David first started studying Harriet in 1936, if he was also able to go back about 70 years also, then he would achieve a date of around 1870.

So where are we at the moment? We know that Darwin collected from three populations: Santa Maria tortoise (Geochelone nigra nigra). San Cristobal tortoise (Geochelone nigra cathamensis) and the Santiago tortoise (Geochelone nigra darwini). Based on Darwin‘s notes all the tortoises collected were juveniles and based on the few sizes given they were probably between one and five years old.


We have an account that the three original tortoises were brought to Australia by John Clements Wickham when he moved to Australia and became First Government Resident of Moreton Bay. Wickham was the First Lieutenant of the Beagle under Capt. Fitz Roy, and later Captain of the Beagle. Wickham never went to the Galapagos so he had to obtain the tortoises of somebody else, the most likely person would be Darwin. Currently we are having mtDNA analysis done to confirm the identifications of Harriet and Tom. Tom as a preserved specimen may not work but we feel that he is worth the risk to try anyway. This will be done by Ed Louis of Texas A & M University. We still have to get to the John Oxley Library and Ian Swingland is looking into things from the English end. Well, this is how the story unfolded so far. The difficult thing to conceive is Harriet's age, to bring this into perspective we have constructed a chronology (Chart 2). To do this we interweave some significant human events into a chronology of events Harriet went through, assuming the story is correct. After all, just imagine being some 167 years old!!

Chronology of Harriet’s life with significant historical events.


Ca. 1830 – 1834: Harriet hatches on Isla Santiago (known at the time as James Island) The first railway is built in the U.S., the Baltimore and Ohio.
1835 – 1836: Harriet is collected by Charles Darwin and taken to England.
1841: Wickham retires from the Royal Navy, moves to Australia and brings three tortoises with him. Lives at Newstead House.
1859: First publication of Darwin’s "Origin of the Species" (Original "On the Origin of the Species by Means of Natural Selection, or The Preservation of Favored Races in the Struggle for Life").
Ca. 1860: Probable time when the three tortoises are placed in the Brisbane Botanical Gardens as Wickham soon left Australia for France. At this time Abraham Lincoln is elected President.
Ca. 1870: Six years before the invention of the telephone by Bell and Edison, we have the earliest first hand account of Harriet.
1882: Charles Darwin dies.
1929: Two years after Charles Lindbergh crossed the Atlantic, Tom dies and is placed in the Queensland Museum at the time of the US stockmarket collapses. It is held the first ceremony of the delivery of the Oscars. Martin Luther King is born.
1952: Harriet moves to Fleay’s Fauna Sanctuary. The Korean war. In a year’s time Stalin will die.
1987: Harriet moves to the Queensland Reptile Park (Australia Zoo) at about the time when Vincent Van Gogh’s painting "Irises" is sold for $54 million in New York.

This Article was recently published in "REPTILTA" The European Herp Magazine, Number 2, March / April 1998.

First published in "Intermontanus" (Publication of the Utah Association of Herpetologists) Vol. 4. Nr. 5 (1995): 33-35.

(1). Applied Ecology Research Group. University of Canberra. P.O. Box 1. Belconnen, ACT, 2616, Australia.

(2). Queensland Reptile & Fauna Park (Australia Zoo), Glasshouse Mountains Tourist Route, Beerwah, Queensland, 4519, Australia.



by Terri Irwin
Director of the Queensland Reptile and Fauna Park (Australia Zoo), Beerwah, Sunshine Coast

The plight of the Crested Iguana was brought to my attention in April 1994 while attending the Herpetological TAG meeting in Darwin. Terry Boylan, from the Taronga Park Zoo, explained that both B vitiensis and B fasciatus needed attention. B vitiensis was found on the island of Yaduataba in healthy numbers of 4000 to 6000 individuals. However, the National Trust of Fiji was having a difficult time finding funding to maintain this island reserve. Returning to Beerwah, Steve and I agreed to visit Fiji to further field study and find out, firsthand, what could be done to help these iguanas.

We arrived in Nadi on July 19th and proceeded to meet with the director for the National Trust, Mr. Birandra Singh, in Suva. Mr. Singh gave us an outline of the $20,000.00 that would be required to get Yaduataba back on its feet as a reserve. Because Yaduataba was already well documented and somewhat inaccessible, we decided to focus our attention on other islands that might have supported Crested Iguanas. We learned quickly that arranging transport could be quite challenging. Four days later we had finally secured a boat and driver to explore the Mamanuca islands. When we visited the resort island of Tokoriki, we discovered two Crested Iguanas in captivity from the island of Modriki. A fellow named Suli tried to claim the pair as his own. As it turned out, the real owner of the iguanas was just away that day.

Eddie Foster was an Australian dive instructor that had lived on the island for the past two years. He and his wife, Karin, had rescued the iguanas when they observed some village children playing football with them. Eddie and Karin had contacted Taronga Park Zoo to ensure the proper care of these iguanas that they named Sun se and Sun se. The Fosters built them an enclosure 6 ½' tall X 2' wide X 3' deep and furnished it with limbs and foliage. The iguanas settled into their captive life so well, in March Sun se laid four eggs. The Fosters immediately installed a heat lamp over the earth substrate where the eggs were laid and monitored temperatures. Since Eddie and Karin would be moving back to Australia in about one month, we discussed the fate of these iguanas and their eggs. First we considered releasing them back on Modriki Island, where they had originally been collected, and bury their eggs there. We discovered, however, that the goats had contributed to the decline of iguanas on Modriki Island. We spent a total of 12 days on Modriki and only three iguanas in their cage on Tokoriki wouldn't work either. Even with the detailed instructions, they were neglected when the Fosters weren't there. We decided to look into Orchid Island at Suva where iguanas were being bred into captivity.

Orchid Island's one remaining Crested Iguana was in very sad shape. He had apparently been housed with other males of his kind in the past and these confrontations had left him terribly scarred. He was brought out on a limb several times a day to be handled by visitors. This visit, again, convinced us to narrow our options. We decided to look into housing Sun se, Se se and their eggs outside of Fiji. We contacted Taronga Park Zoo and the job of exporting began.

On the 29th of July we arranged to meet with members of Fiji's government and the chiefs of the Mamanuca Islands to discuss the future of Modriki's Crested Iguanas. As the National Trust had no funds for this trip, we agreed to hire a large boat at $110 per hour to accommodate them. Our meeting was a traditional Sevu Sevu. Even our clothes had to be altered to the Fijian style. We shared the customary drink of Kava (or Yunguana as the locals call it) and then it was down to business. The entire meeting was conducted in the native Fijian language, so we had an interpreter with us from the National Trust. The word "vokai" was mentioned quite often as that means "iguana". Often the chiefs would burst out laughing and I didn't need to be told what they were laughing at. They obviously thought we must have been a little bit crazy to spend so much time and effort on a little green lizard! We discussed with them the problems the goats were causing the iguanas. When we asked how many goats were on the island, we were surprised to hear there were less than 100. Then our interpreter explained that the villagers have difficulty comprehending numbers over 100. When we asked permission to remove the goats from the island, they said that was definitely not an option because they occasionally sold goats to the other villages. Goats are difficult to control, anyway, because only the military police are allowed firearms! So we then requested the next best thing. Would we be allowed to fence the goats out of the iguanas' territory? The most viable habitat was about 400m X between 100m & 300m. The chiefs agreed to consider this option and discuss it at their next Sevu Sevu in one month's time. There is a lot of pride with these villagers and their islands. So, even though they have no legal right to the iguanas, it is much better in the long run to work cooperatively with them. We also had to be careful not to give them the impression that the iguanas might be worth money to them, or it would simply mean more would be illegally collected. They did ask for our help acquiring a desalinisation plant. This would enable them to plant crops for profit over their entire island, effectively destroying the island's natural habitat. We began to understand that the villagers really believed we were somehow profiting out of our research work. You can't blame them for wanting a slice of the pie. We wouldn't have to teach the Fijians the true meaning of conservation. Not an easy thing to instill in people who can't comprehend extinction.

The 1st of August brought us news that we weren't prepared for. Because of a medical situation with Karin, Eddie would need to leave for Australia immediately instead of in one month as originally planned. We could not realistically afford to stay and take care of Sun se, Se se and their eggs until the permits came through. Luckily, Tokokiri's manager came to our rescue. Jan Raymond allowed us to stay at the resort and in the dive master's quarters for a total of six nights free of charge. This was essential in order to oversee the incubation of the eggs. Even so, Steve and I were now dipping into our personal savings to keep going. Our time on Tokoriki was spent caring for the iguanas as well as teaching the villagers about them. They helped us gather food for the iguanas. Everything from Hibiscus blossoms to grasshoppers! Our seventh night was spent at Yanuya village. Our hosts were Jope and Rachael Samilla and they prepared a wonderful dinner including their locally grown cassava. This potato-like vegetable was part of their staple diet. Our evening was spent with no electricity, running water, or telephone.

Just lots of children eager for wildlife stories!

The next day we headed back to the main island to search for Modriki iguanas that had been sold as pets. The iguanas we managed to trace had all died. The iguanas that had been sold at the Lautoka markets were untraceable. Selling for between $4.00 and $5.00, they had simply disappeared.

On August 11th, our plans were going to be changed yet again. We had just returned from Tokoriki, Steve decided to remove the eggs from the incubator he built in the dive master's room and put them back in the ground, since we couldn't look after them daily. Steve thought this was best. As we arrived back at Nadi, Steve jumped out of the boat and landed on a shell. It cut his foot like glass. To avoid the risk of infection, we decided to go back to Australia and would stay in Fiji until the permits came through. With Steve gone, and miles of red tape to get through, I called my mother in the States to come and give her experienced assistance.

The day before we arrived we met Birandra Singh in Suva and drove to Singatoka to see the now closed Kula Bird Park. It definitely has the potential to be developed into a zoological facility. Something I think Fiji desperately needs.

Our most exciting week came on August 15th when we discovered a living pet iguana from Modriki Island. Lemeki was living in a village near Nadi and his iguana lived in the Breadfruit tree in his front yard. He had been given the iguana in April 1993 when he was returning from Yanuya Village. He said that there were several iguanas on the boat that had been collected from Modriki Island after a hurricane earlier that year. This was the largest Crested Iguana I had seen yet, in spite of the fact that the end of his tail was missing. Lemeki informed me that the villagers had chopped it off believing it could whip them and injure them! Lemeki was a retired school teacher and agreed to help teach the Yanuya Villagers about the iguana in their native tongue if the need ever arose. I felt a special bond with Lemeki because the local people thought we were both crazy for loving the iguana. When I called Steve he had good news of his own. The permits had finally come through and I could pick up Sun se, Sun se and their eggs on the 17th and catch a flight to Australia on the 18th.

Mom and I decided to pick them up on a helicopter as the eggs would never survive through rough seas in a little boat. When we arrived at Tokoriki, everyone seemed very sad, almost in mourning. No one would tell me what was wrong until I was given a letter from one of the young chiefs of Yanuya Village. The letter said that the chiefs had changed their minds and we couldn't have the iguanas and their eggs after all. After a panicked call to Australia, we agreed I should meet with this chief and straighten things out. Before I left for Yanuya Village, I bumped into some Fijians I hadn't seen before. They wouldn't answer me when I greeted them in English or Fijian, I became worried that maybe they were going to take the iguanas. I decided to ask Jan, the manager, to look after the iguanas while I went to the village. She agreed, so I bagged them and left them in her office. I figured the eggs would be safe where they were. My meeting with Saramiah was unsuccessful. He explained that permission could not be given to take the iguanas until after the next Sevu Sevu in one month's time. I returned to Tokoriki with the difficult choice of what to do. As the helicopter approached, I knew I couldn't leave them. Mom carried the eggs in a container supported by my hat and the iguanas went in my duffle bag. Breathless, we made it to the helicopter. When we returned safely to Nadi, I called Steve to let him know what happened. We agreed it was the best decision. Since all the locals were aware of our work and knew we were supposed to be leaving with the iguanas. Steve thought it would be safer if Mom and I moved to another location this last night. Without telling anyone what we were carrying, we transported our iguanas and eggs across town. Mom was careful to keep the eggs away from any air conditioning drafts.

My flight to Australia was scheduled for 4.05am, so we arrived at the airport just before 2.00am. I was exhausted and ready to go home when the staff at the export department informed me that all cargo had to be put on the plane by 1.00am and now it was too late. After explaining to them that this was the first I knew that I had to be three hours early, not two, they basically didn't believe me! I finally had to wake Birandra Singh and have him convince them by phone to load my cargo. At least they listened to the Director of the National Trust!

This adventure had a happy ending for Sun se and Se se, but what of the iguanas in the wild? I am very proud of the people we met and the work they are doing to help save them. Birandra Singh even got us air time on national television to tell the Fijians about their iguanas. But we couldn't stop there. We met with members of Taronga and Melbourne Zoos as well as Eddy and Karin to discuss what to do next. There are many zoos around the world concerned with the plight of these iguanas. Happily, two of the four eggs we transported have hatched and it appears that Sun se is gravid again. There are no easy answers to the problems facing the Fijian Crested Iguanas. Alone, one zoological facility could never save them. Together, we can encourage the Fijians to be proud of these "Jewels of the Pacific". Let's join with other zoos like Taronga Park and help with this worthwhile project.

Let's save the Fijian Iguanas.

Vanaka Vaka Levu
Thank you very much

This Article was presented at the ARAZPA/ASZK CONFERENCE, PERTH, APRIL 3-7 1995.

by Kelsey Engle
Australia Zoo (formally Queensland Reptile and Fauna Park), Beerwah, Sunshine Coast

The Canopy Goanna (Varanus keithhornei) is a slender, arboreal monitor from north-east Australia (Cogger1996). It is restricted to the tropical rainforest of the upland and lowland regions within the Iron and McIlwraith Ranges of Cape York Peninsula (Irwin 1994). The holotype was one of three individuals collected in 1978 at Buthen Buthen east of Coen, far north Queensland (Czechura, 1980) and due to the absence of convincing evidence, these first specimens were tentatively assigned to the nominate race of V. prasinus prasinus (Czechura, 1980). In 1985, Wells and Wellington re-examined these specimens and found sufficient morphological variation to designate them as a new species, Varanus keithhornei. Sprackland redescribed these same specimens again in 1991 as Varanus teriae, however as no reference was made to the previous description of Wells and Wellington the two descriptions have been synonymised as V. keithhornei (Covacevich & Couper 1994).

In 1988 the Queensland Reptile and Fauna Park (QRFP) at Beerwah obtained permits from the Queensland National Parks and Wildlife Service to collect two specimens of V. keithhornei from the wild. Unfortunately, one specimen sustained injuries during the capture and died shortly after arriving at the park. The second specimen, presumed to be a male, flourished in captivity for the next five years in the absence of conspecifics and at this time a second permit to take was granted to allow for the establishment of a captive breeding program at the QRFP. This species in the wild has an elusive nature, making behavioural and/or reproductive observations virtually impossible; hence, a captive situation offered the best opportunities to observe and record this important information. In November 1993 three specimens, one male and two females, were collected from Iron Range in Cape York Peninsula (Irwin 1996 a).

Captive Management
During the initial stages of housing, the three new specimens were kept on public display. The original male collected in 1988 was paired with one of the new females, while the second pair was housed separately. The first pair was seen to copulate at least twice during their time together however no nesting behaviour arose from this activity and the male died shortly after from acute leukaemia. It is thought his condition may have contributed to the lack of mating success.

After the death of the original male the three remaining lizards were moved into
off-display housing. This enclosure measured 2.2m high x 2.0m long x 1.4m wide and was maintained at temperatures ranging between 20 and 28 C in winter and 24 and 33 C during summer. A hinged roof and a removable glass panel on the door allowed access to direct sunlight in fine weather. The substrate within the enclosure consisted of hard wood-chip and eucalyptus leaf litter. A water bowl provided fresh water at all times (Irwin 1996 a).

Due to the shy nature of these lizards, food initially was left unattended in small feed dishes within the enclosure. However, once established, the lizards would readily take food from the keeper, ensuring that a strict record of the dietary intake of each individual could be maintained. The lizards adapted well to a diet of small rodents and were also offered crickets, beetles, grasshoppers and, very occasionally, small pieces of fruit. Once established, better replicate wild conditions, their diet was modified to consist almost entirely of insects, with a pink mouse only being offered about once every two weeks (Irwin 1996 a, Sprackland 1994 a).

a) Mating and oviposition

Eight weeks after transferring the lizards to the new enclosure three eggs were found scattered across the floor. These died early during incubation or were, most likely, infertile. Between 1994 and 1997, the two females had produced eight clutches between them. All were hard, often discoloured and failed to hatch. On each occasion the eggs where laid in various locations with neither female seeming to have a preferred laying site. Numerous nest sites were offered including a termite mound, hollow logs (empty or filled with various substrates such as sand, potting mix or sphagnum moss), an open sandpit and an open sphagnum pit. The various nest sites, where possible, were trialed high above the ground as well as at ground level. During this time none of these nests were utilised for egg deposition and neither female was ever seen to investigate any of these options although they had been observed frantically searching for suitable substrate during the period prior to laying (Irwin 1996 a).

After a female had been mated, she became very aggressive towards the male and other female. Bites and scratches would be inflicted, with the aggression reaching a peak just prior to and following nesting activity. Even during the period of suspected ovulation and mating, small scuffles between the females would occur and on occasions aggression would also be shown towards the male. It became clear from this interaction that the smaller of the two females was the dominant animal and due to her persistent aggression, she was removed from the main enclosure and housed alone. Only once eggs had been laid would a female be removed from the male and replaced by the second female.

In order to reduce the females' frantic searching behaviour prior to laying, a nesting box designed to replicate a rotten log was constructed. The box had internal dimensions of 124mm x 680mm x 245mm. It was totally enclosed with a hinged lid for keeper access. The entrance was a small, elongated opening 25mm high and 7.2mm wide, positioned 190mm from the bottom of the box. An overhang of 75mm out from the box and 90mm down the side was placed around the entrance to provide extra security for the female (Fig. 1). The nesting substrate consisted of a layer of damp sphagnum on top of a 110mm layer of moist sand. A gap of approx. 30mm was left at the top of the box. A heat pad was placed underneath the box. Due to external temperature fluctuations, the internal temperature of the box varied from between
27 - 33°C.

The subordinate female was the first to use this nest box for the first time she deposited four eggs overnight on 23 January 1997. These were placed in the incubator at a 1:1 ratio of vermiculite to water by weight. These eggs although appearing better than previous clutches, were still discoloured and probably not fertile. They were discarded within a month of laying. The second female also deposited a clutch of eggs but scattered them throughout the enclosure. These eggs were of a similar appearance and also infertile.

As the lack of fertility was thought to be related to inadequate heating, a heat lamp was installed to allow the lizards to obtain higher body temperatures. This produced a basking site between 42 and 47 C and was frequently use by the male. However, it was rarely used by either female even after a second basking position was offered, allowing both occupants to bask simultaneously

The nest box was also modified in two ways. The sandy nesting substrate was replaced with a moist potting mix as this was though to better replicate the substrate from which V. prasinus hatchlings have been seen to emerge from in the wild (Sprackland 1989). The underfloor heat pad was also replaced with a strip of heating tape (85mm wide) placed along the inside wall of the box, allowing for a 55mm gap without heat at the box entrance. This modification in the placement of the heat source resolved the original problem of the heat increasing as the female dug down and gave the female greater options by providing a horizontal thermal gradient within the nest box. It was hoped that these two minor alterations, would encourage the use of the box for egg deposition.

Matings were observed on 14, 18, 26 and 28 January 1997. Throughout this period the male was constantly observed on top of the female, sometimes seeming to be resting in that position. Copulation was obvious as the tail base of the male would be wrapped entirely underneath the female's and on some occasions it was possible to view the hemipene itself. While the female was receptive to the male, the two were constantly in contact with each other, the female never objecting to the close proximity of the male. , As the time of egg deposition approached the female became less receptive, the male tended to lose interest in her and the pair spent most of their time on opposite sides of the enclosure. Once the eggs were laid the male actually avoided contact with the female. In this instance, by 3 February 1997, the pair was spending less time together and their individual behaviour returned to 'normal' with each lizard sunning at separate locations for most of the day.

This female first entered the nest box at 4pm on 2 March 1997, 47 days after the first observed mating. It is assumed she did not emerge during the night and remained inside the nest box until 8.30am the next morning. Four eggs were immediately removed from the nest box for artificial incubation. These eggs, unlike previous clutches, were full in appearance with no obvious discolouration (Table 1.). The female did not re-enter the box at any stage after egg deposition however, the male did seem more cautious of her at this time indicating possible aggression by the female towards him. At no time during courtship, mating or egg development did this female's food intake vary. However, as with all of the previous nestings, the female was ravenous after laying, snatching all food offered to her. This aggressive feeding behaviour lasted for 2-3 days.

The eggs were discovered nestled under the sphagnum moss and marginally dug into the potting mix substrate. The temperature at the site of egg deposition was 33 °C. The surface of the sphagnum had a thermal gradient from the entrance back, which ranged from 23 - 29°C at the time of egg collection. All eggs were adhered, the entire clutch weighing 57g and an average egg weight of 14.3g.

A few days after laying, this female was removed from the enclosure and the subordinate female was placed in with the male. The male immediately showed interest in her. It had been noticed that during the period of separation from the male, this female's abdomen became very slightly distended, possibly indicating ovulation. Although copulation was not observed, at all times the male was lying on top of the female. This female did experience a slight change in feeding pattern when she refused part of the food offered to her three days before laying. She finally entered the nest box at 3pm on 15 April 1997, 44 days after first being introduced to the male and although she was not present in the box the next morning. Three eggs were laid beneath the sphagnum, nestled into and lightly covered in potting mix (Table 1.). These eggs were also laid at the opposite end (the entrance) to the previous clutch and the site temperature was 31 C. All three eggs were stuck together, the outer two showing a better appearance than the middle egg which was elongated and slightly discoloured. The total mass of the eggs was 44g and average egg weight of 14.7g.

b) Incubation

Both clutches of eggs were placed in plastic containers in a vermiculite: water ratio of 1:1 by weight. Incubation temperature was 29-30 C and humidity was kept as high as possible. Both clutches were also left as single egg masses.

One of the eggs in the first clutch began to discolour during the tenth week. As it was attached to the other three eggs within the clutch, it was feared that this could cause those remaining eggs to also deteriorate. The following technique was utilised to prevent the possibility of contamination of the rest of the clutch should the egg have torn during removal. The clutch was removed from the vermiculite substrate and the 'suspect' egg pierced with a large hypodermic needle. The contents of the egg were off colour and slightly cloudy, possibly indicating a fertile egg which had died during incubation. The major portion of the shell was then cut away from the surrounding eggs, the actual contact points being carefully removed so as not to damage the shell of the viable eggs.

As the cause of the sudden deterioration of this egg was unclear it was decided to trial a different incubation technique. In the past this alternate technique had been used on Green Python (Morelia viridis) eggs with great success (Mannion 1996) and, due to the overlapping distributions of these two species, it was thought that the conditions should be ideal for the V. keithhornei eggs also. The three remaining eggs were placed in a large plastic garbage bin half filled with a vermiculite/water mix at a ratio of 3:1 by weight. The eggs were half-buried and the container sealed with a glass lid. To ensure an even temperature throughout the incubator, a fan was continuously operated to circulate the air. Incubation temperature remained the same ranging between 29-30 C.

On day two of the second clutch's incubation the substrate mixture appeared too dry; no condensation had formed on the lid of the container. A small amount of water was added to the edges of the mix to avoid physically disturbing the eggs. Day three revealed a small amount of condensation forming on the container lid and it was decided that the mixture was sufficiently moist. By day seven the condensation had increased further, although not to the extent of the first eggs.

After 42 days, the presumed infertile egg in the second clutch began to discolour and it was decided to follow the same procedure that was adopted for the discoloured egg in the first clutch. However, as the hypodermic needle was inserted it became apparent that the contents of this egg were virtually solid, the difference in viscosity being attributed to egg infertility. Instead a scalpel was used to slice the egg away from the rest of the clutch revealing its consistency to be similar to gelatine. Again, the attached portions of the shell were carefully removed, resulting in no damage occurring to the viable eggs. This clutch completed the incubation period in the original manner with no further problems being encountered.

c) Hatching and neonate rearing

The eggs of the first clutch began to sweat the day of hatching. The first hatchling emerged on 20 August 1997, 170 days after laying. The second egg hatched overnight and the last hatchling emerged the following day. All three were in excellent condition and extremely active. At hatching each lizard weighed 10g and their total length ranged between 232mm and 251mm (Table 2.).

The second clutch swelled due to absorption of moisture from the incubation substrate. Both eggs looked healthy; however, one egg was noticeably larger than the other. The larger, 'normal sized' egg was first to hatch after 180 days of incubation. This individual weighed 12g at hatching and had a total length of 243mm but did have a considerable amount of yolk sac left unabsorbed. The hatchling was placed into a plastic tupperware container on moist paper towel and left in the incubator until the sac was absorbed.

The second egg began to sweat, but had failed to hatch by the end of that day. Due to concern over the health of this hatchling the egg was manually opened to expose a fully formed but extremely small and weak lizard. This individual also had yolk left unabsorbed and was set up in the same manner as the first lizard. During this time breathing appeared laboured and the hatchling barely moved. It died 3 days after hatching.

All three hatchlings from the first clutch remained in the incubator for one day after hatching and were then placed into an enclosure measuring 500mm x 420mm x 700mm. The front side of the enclosure was set at 45 and fitted with stainless steel wire mesh to allow access to direct sunlight. They were provided with leaf litter substrate and fresh fig branches for climbing, the latter also providing increased humidity. A water bowl provides access to fresh water at all times. The hatchlings have been observed drinking from the bowl and also swimming in it. Mist spraying of the enclosure occurs at least twice daily. These young lizards, although shy, were not as nervous as their parents and settled well into their captive environment.

The survivor from the second clutch was set up in a similar manner once its health was considered satisfactory. The temperament of this lizard was markedly different. It was extremely nervous when being observed and would not accept food from forceps, hence it was housed separately.

All four hatchlings were very similar in appearance, but were markedly different from their parents' colouration. The markings on the hatchlings were quite vivid, having a black background with distinct silver chevrons across the entire body (Fig. 2.). The head from the eye region forward is entirely silver. As with many varanid species, the juvenile specimens are far more spectacular in colouration and although the body pattern is discernible on the adults the colours have dulled and merged along the greater part of the body.

The small dead hatchling from the second clutch weighed only 5 grams and was donated to the Queensland Museum. Samples from this lizard are being used for genetic analysis of the V. prasinus group.

As far as is known, this marks the first successful captive reproduction of V. keithhornei. There are no published accounts of its reproduction in captivity, either as V keithhornei or V. teriae, however a number of the observations recorded here and in earlier papers are similar to those noted for V. prasinus, arguably the species most closely related to V. keithhornei. These include the raking of prey items during feeding (Greene 1986) and the 'sticky' surfaces of the feet (Czechura 1980).

The behaviour of withholding eggs only to scatter them around the enclosure at a later date, has also been observed in captive V. beccarii, another closely related species (B. Eidenmuller, pers. comm.), as well as captive V. tristis orientalis (Horn & Visser1997) and V. acanthurus (P. O'Callaghan pers. comm.). It is possible that the female's behaviour was a searching response for an unoccupied territory in which to lay her eggs. Similarly, the appropriate biotic or abiotic triggers may not have been in place for oviposition, as noted by Horn & Visser (1997).

Adult V. keithhornei and hatchling V. prasinus have been observed utilising tree hollows in the wild (Irwin 1996 a, Sprackland 1989). These observations, combined with information on the captive breeding of V. beccarii and V. prasinus (Barker 1985, Eidenmuller 1996, Sprackland 1994 b), resulted in the development of the nesting box which was successfully used by the females at the QRFP.

The detection of a gravid female can be difficult in V. keithhornei. In late developmental stages, many varanid species become noticeably distended in the abdomen. This is not the case with V. keithhornei as the abdomen will become only slightly distended and feeding habits will not always alter. This is also said to be true for captive V. gilleni (M. Vincent pers. comm.). For many varanids, changed feeding habits can be a reliable indication of when a female is preparing to nest (Irwin 1996 b). Female V. keithhornei do not dig test holes and there is no investigation of the nest site until immediately prior to laying. The best guide to determining the time of nesting is if copulation is observed, or the male shows a sudden increased interest in the female.

A difference in appearance was noted during incubation between the two egg masses and is likely to be the direct effect of the different methods of incubation adopted for each clutch. The first clutch, which adopted the same technique used at Dallas Zoo for V. prasinus (Barker 1985), did not noticeably change in size throughout the entire incubation period whilst the second V. keithhornei clutch, incubated using the most common technique for varanid egg incubation, showed a substantial change in appearance. The latter absorbed moisture, significantly increased in size and a few days prior to hatching the healthy egg partially collapsed. This scenario has been typical for varanid eggs incubated in this manner at the QRFP in the past (S. Irwin pers comm.; pers obs.). This difference between the eggs' development was also reflected in the hatchlings; the first three being active and strong upon hatching while the second technique produced weak individuals with unabsorbed yolk. It has been suggested that, perhaps due to the drier conditions within the first situation, the developing embryos required the moisture from the egg sack to survive and so absorbed it more quickly (S. Thomson pers. comm.). It has also been suggested that insufficient air circulation toward the end of the development may cause the neonates to emerge before being fully developed. Whether this outcome was a reflection on the physical conditions of the two clutches, or the incubation techniques utilised is difficult to determine and requires further investigation.

The period between mating and oviposition is usually 6-7 weeks, which is longer than the 4-6 week period given by Horn (1980, Horn & Visser 1989). However, the 179-190 day incubation period does compare with the periods collated by Horn & Visser (1997) for nine recorded captive breedings of V. p. prasinus and V. prasinus beccarii. This may be expected due to the close taxonomic relationships between these species and as such initial predictions of incubation were based on this information.

Because of its arboreal habits and cryptic nature, this species offers many challenges for successful captive maintenance, breeding and public display. It is hoped that a greater understanding of the requirements of these lizards in captivity will give us a greater insight into their lives in the wild.

I would like to thank all that have contributed to the development of this paper but there are a few people in particular who without I may never have completed this paper.

Thank you to Steve Irwin who provided the opportunity to work with this species and many others. His comments, suggestions and enthusiasm were invaluable to not only the writing of this paper but also the success of the project. Chris Banks. Thank you for the time and effort taken in reviewing drafts of this document. Your comments were appreciated and well received. Finally thank you to Paul O'Callaghan who also took the time to review this paper and provided support throughout its development. Thank you all once more.

Table 1. Dimensions of V. keithhornei eggs at oviposition at QRFP.

Egg No. Length (mm) Width (mm)
Clutch 1
1 49.0 23.0
2 53.0 21.5
3 50.0 22.0
4 51.5 21.5
Clutch 2
1 (top) 51.1 23.1
2 (middle) 54.1 20.0
3 (bottom) 51.2 21.0

Table 2. Dimensions of hatchling V. keithhornei at QRFP.

Lizard No. Weight (g) Snout-vent length (mm) Total length (mm)
Clutch 1
1 10 100 251
2 10 97 239
3 10 97 232
Clutch 2
1 12 101 253

Barker, D. (1985) Maintenance and reproduction of Green Tree Monitors at the Dallas Zoo. In: 8th Annual International Herpetological Symposium on Captive Propagation and Husbandry. pp91-92.

Cogger, H.G. (1996) Reptiles and Amphibians of Australia, Fifth Edition.
Reed Books Australia, Victoria.

Covacevich, J., Couper, P. (1994) Type specimens of frog and reptile species in the Queensland Museum: recent additions and new information. Mem. Qld. Mus. 37(1):53-65.

Czechura, G. (1980) The Emerald Monitor Varanus prasinus (Schlegel): an addition to the Australian mainland herpetofauna. Mem. Qld Mus. 20(1):103-109.

Eidenmuller, B. (1996) Keeping and breeding the Aru Black Tree Monitor Varanus beccarii (Doria, 1874). Reptiles. December: 76-83

Greene, H. (1986) Diet and arboreality in the Emerald Monitor, Varanus prasinus. Fieldianna: zoology (31):1-10.

Horn, H.-G. & Visser, G. J. (1989) Review of reproduction of monitor lizards, Varanus spp. Int. Zoo Yrbk. 35:227-46.

Horn, H.-G. & Visser, G. J. (1997) Review of reproduction of monitor lizards, Varanus spp. Int. Zoo Yrbk. 28:140-50.

Irwin, S. (1994) Notes on the behaviour and diet of Varanus teriae Sprackland, 1991. Mem. Qld. Mus. 35(1):128.

Irwin, S. (1996 a) Capture, field observations and husbandry of the rare Canopy Goanna. Thylacinus. 21(2):12-19.

Irwin, S. (1996 b) An innovative strategy for the detection of egg-deposition in captive Varanid reptiles. Herpetofauna. 26(1):31-32.

Mannion, W. G. (1996) Maintenance and captive reproduction of the Green Tree Python, Morelia viridis, at the Queensland Reptile and Fauna Park. Thylacinus. 21(3b):14-17.

Sprackland, R. G.(1989) Captive maintenance of Green Tree Monitors (Varanus prasinus) and their kin. Captive Propagation and Husbandry - NCHS 1989:49-56.

Sprackland, R. G. (1991) Taxonomic review of the V. prasinus group, with distinctions of two new species. Mem. Qld. Mus. 30:561-76.

Sprackland, R. G. (1994 a). Carnivorous lizards and their diet. The Vivarium. 5(5):12-14.

Sprackland, R. G. (1994 b) Emerald Monitors: lean green and rarely seen. Reptiles. June:16-23.

Wells, R. W. & Wellington, C. R. (1985) A classification of the Amphibia and Reptilia of Australia. Aust. J. Herpetol. Suppl. Ser 1: 1-16.


Richard and a Rusty Monitor
Richard and a Rusty Monitor

By Richard Jackson
Australia Zoo (formally Queensland Reptile and Fauna Park)
Beerwah, Sunshine Coast

Varanus semiremex (the Rusty Monitor) was described in 1869. Despite this species being recognized for so long, little is known about it in the wild or captivity and it is regarded as one of Australia's many poorly known reptile species (Bennett, 1995; Cogger et al., 1993). Captive specimens of V. semiremex have been held in the last thirty years in Germany, the United States of America and Australia, however no detailed observations have been published on its breeding habits and maintenance. V. semiremex is a coastal Queensland species (Cogger, 2000) whose habitats and its continued survival are threatened by clearing, thus it seems timely to report the results of recent observations in the wild, and captive breeding work. This study was undertaken under permits issued by the Queensland Parks and Wildlife Service, in the field (Rockhampton district) and at Australia Zoo, Beerwah, Queensland.

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