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“Lean, green and rarely seen”: enthralling prasinoid tree monitors

The views expressed are those of the author and are not necessarily those of Scientific American.

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Captive Emerald tree monitor (Varanus prasinus). Image by TimVickers, in public domain.

I said in the previous Tet Zoo article on monitor lizards that I really wanted to cover the prasinoids; that is, the arboreal tree monitors of New Guinea, Cape York Peninsula and various of the islands surrounding these areas. So, let’s get to it. Tree monitors or prasinoids, also termed the Varanus prasinus species group, are slender-bodied, gracile monitors with pointed snouts and especially long, prehensile tails. They tend to be green: some are lime green and some are deserving of another common name, ‘Emerald tree monitor’. Some are patterned in ringlets or chevrons; others, however, are virtually black while others are yellowish. They have brown-orange eyes and pink tongues. Total length can be 110 cm or so but 60-80 cm is more common. [Image below by Greg Hume.] Incidentally, the quote used in the title for this article comes from an article about these amazing lizards by Sprackland (1994).

Beautiful Blue-spotted tree monitor: note the long, slender digits and very sharp, curved claws. Image by Greg Hume, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

It is, essentially, universally assumed that tree monitors are specialised for arboreal life, and that they spend much (though not necessarily all) of their time foraging high up in trees. Note that, across many animal groups, assumptions like this are sometimes based on anecdotal impressions and are not really backed up by detailed ecological studies or by the discovery of anatomical features linked with any specific lifestyle or behavioural preference. Furthermore, ‘obvious’ anatomical features assumed to be adaptations might not always mean what we assume they do: a prehensile tail looks like a good arboreal adaptation, for example, yet prehensile tails are also present in animals that aren’t specialised tree-climbers (examples: the turtle Platysternon, the alligator lizard Gerrhonotus liocephalus).

These issues inspired Greene (1986) to specifically examine the evidence for arboreality in prasinoids. He concluded that their green colouration, prehensile tails and unusual foot scales – all unusual features within the monitor lizard radiation – really are specific adaptations to arboreal life (Greene 1986).

A climbing prasinoid (I'm not sure which species this image depicts: it's redrawn from a photo in Kirschner et al. (1996)). Note use of the prehensile tail. Image by Darren Naish.

Prasinoid hands and feet are especially interesting. Black, raised subdigital scales are arranged in transverse rows and look very much as if they might provide these lizards with enhanced grip while climbing. Their palms and foot soles have been described as feeling usually soft or even sticky by some authors. The fact that the subdigital scales are black is interesting. If you have a good memory (or if you know this anyway), you’ll recall that melanin-rich wingtips in birds might represent an adaptation to minimise feather erosion and enhance resistance (see this Tet Zoo article on patterns of pigmentation in petrels). Could it be, then, that the melanin-enriched subdigital scales of prasinoids evolved under similar evolutionary pressure? (Greene 1986). It’s an intriguing idea.

Studies of prasinoid stomach contents reveal arthropod-dominated diets that include katydids, grasshoppers, beetles, centipedes and spiders. Captive animals will eat fruit but there’s no indication as yet that this is typical for wild ones – it’s certainly plausible that they might eat fruits, nectar and so on on occasion: some monitors are habitual frugivores and the ingestion of plant products by lizards has proved more widespread than long assumed. Large and formidable animal prey are eaten on occasion. One prasinoid had eaten a Eurycantha stick insect 12.4 cm long, an insect famous for its large, thorn-like leg spikes. However, the insect was missing several of its legs (Greene 1986), perhaps because the lizard had removed them before swallowing it. A specimen of the arboreal mouse Melomys has also been recovered as a prasinoid prey item (Greene 1986). The general picture that emerges is that they forage among arboreal vegetation, mostly searching for small katydids and similar insects but occasionally grabbing large insects and small mammals.

Illustration of Emerald tree monitor (V. prasinus): identifiable by dark, chevron-like dorsal markings (and, if this were in colour, overall green colour). Image by Darren Naish.

Observations of individuals seen in close proximity have led to suggestions of a gregarious nature for these varanids (Irwin 2004). Females have been reported to guard the tree hollows in which they lay their eggs, sometimes both before and after laying has occurred. Females have also been known to lay their eggs within arboreal termite nests. Prasinoids climb and scurry up trees and along branches when escaping predation or harassment but “If the threat continues, they launch themselves out with all four legs splayed – any contact with any foliage will result in the lizard clinging to it” (Irwin 2004, p. 405).

For at least a few decades during the late 20th century, just a single prasinoid species was identified: Varanus prasinus, the Green tree monitor, suggested by Robert Mertens in 1959 to consist of four subspecies. Sprackland (1991) suggested that one of these ‘subspecies’ should be regarded as distinct from V. prasinus, and thus resurrected V. beccarii of New Guinea and the Aru Islands. This is a very dark prasinoid – it’s sometimes called the Black tree monitor – and it’s also one of the largest member of the group. [Image of Black tree monitor below by Greg Hume.]

Black tree monitor (V. beccarii), photo by Greg Hume, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.

Sprackland (1991) further argued that V. kordensis – also regarded by Mertens as one of those V. prasinus subspecies (it was originally named in 1874 as a distinct species) – should be regarded as synonymous with V. prasinus, the supposed differences falling within tolerable limits of intraspecific variation. Since then, however, the case for V. kordensis as a distinct species has been made again: V. kordensis differs from V. prasinus in being darker green, in being decorated with ocelli instead of stripes, and in possessing distinct (lower) scale counts across the head and body (Jacobs 2004). Other workers also consider kordensis as distinct, but only as a subspecies of V. prasinus. Remember that these decisions are ultimately subjective. There’s agreement that kordensis represents a lineage close to prasinus, but is it close enough to prasinus to be included within it, or should it really be regarded as outside of it? Similar issues affect the other prasinoids. Regardless, kordensis is unique to western New Guinea, occurring also on the nearby islands of Biak and Yapen (Jacobs 2004).

Prasinoids in Australia: Canopy goannas

Anecdotes suggesting the presence of prasinoids on the Australian mainland were reported in 1975. These were confirmed in 1978 when Gregory Czechura collected a dark prasinoid from northern Queensland; two more Australian specimens were collected later on (Czechura 1980). Czechura identified these monitors as part of V. prasinus but Sprackland (1991) argued that their presence of conical (rather than flat) throat scales, anteriorly positioned nostrils and yellow chevrons and tail rings indicated the need for separate species status, and thus the name V. teriae was born… the name honours Sprackland’s wife. I suggested the possible common names Cape York tree monitor or Teri’s tree monitor for this species (Naish 1998).

Canopy goanna, image by Darren Naish. The fingers should be longer and claws should be larger and more strongly curved.

However, Wells & Wellington (1985) had already suggested the name Odatria keithhornei for the same taxon (V. teriae and O. keithhornei are both based on the exact same specimens). These names are objective synonyms if we accept the Wells and Wellington names as available: as many of you will know, controversy exists as to whether these names really are available. Debate continues, but many Wells and Wellington names are now in technical use, and V. keithhornei – vernacularly the Canopy goanna – was used in a major recent volume on varanids (Irwin 2004).

Having mentioned Wells and Wellington, I should note Hoser published his own ‘revision’ of monitors during 2013. This included new generic and tribe names for the prasinoids, along with much else besides. It may not surprise you to hear that I’m not going to use or mention any of his taxonomic suggestions. See Kaiser et al. (2013).

Wild Canopy goanna; image (c) Stephen Zozaya, used with permission.

The new ones

Sprackland also raised V. bogerti (originally named by Mertens in 1950) to species level. This is an especially dark prasinoid, entirely lacking stripes, rings or chevrons. And Sprackland (1991) also named the entirely new V. telenesetes, a green animal endemic to Rossel Island, way out to the west in the Louisiade Archipelago, west of mainland New Guinea. This far flung occurrence explains the species name, which means ‘far island dweller’ (Sprackland 1991).

Golden-speckled tree monitor (V. boehmei); image by Matthias Zepper, licensed under Creative Commons Attribution 3.0 Unported license.

More recently, Böhme & Jacobs (2001) named the beautiful Blue-spotted tree monitor or Blue tree monitor V. macraei. This is a highly distinctive prasinoid marked with brilliant blue ocelli, first discovered as a German import for the pet trade. So far as we know, this species is endemic to Batanta, a small island off the western coast of New Guinea’s Vogelkop Peninsula. Batanta is located to the south of the larger island of Waigeo, and Waigeo has also proved to be the home of another recently named prasinoid: the Golden-spotted or Golden-speckled tree monitor V. boehmei (Jacobs 2003). This species looks similar to the Australian Canopy goanna and some authors have argued that it’s not especially close to the Blue-spotted tree monitor, instead being closer to V. beccarii and V. kordensis (Böhme & Jacobs 2004). However, Ziegler et al. (2007) found V. macraei to be closest to a V. boehmei + V. prasinus clade.

Specimen identified as Reisinger's tree monitor (V. reisingeri) (but is it? I'm not 100% sure): there are lots of photos of captive individuals online, but this is about the only one that's clearly CC. Image by Vincent Malloy, licensed under Creative Commons Attribution-Share Alike 3.0 Unported.

Most recently, Reisinger’s tree monitor V. reisingeri was named (Eidenmüller & Wicker 2005): a greenish-yellow animal apparently endemic to Misool Island, just to the west of Vogelkop Peninsula but further south than Batanta. Very little is known about this monitor and its position relative to other prasinoids has yet to be discussed in print (so far as I know). Again, it was first discovered in captivity – as the property of an Indonesian wildlife dealer. Specimens are now available quite widely – I’ve seen them here in the UK. The trade in tree monitors sure looks like a serious problem that requires action… please read on.

If all the taxa discussed in this article (and elsewhere) are regarded as distinct species, the V. prasinus group includes as many as nine species (V. prasinus, V. beccarii, V. kordensis, V. keithhornei, V. bogerti, V. telenesetes, V. macraei, V. boehmei and V. reisingeri). Where do these monitors fit within the varanid radiation? Mertens included then within Odatria, the almost wholly Australian ‘dwarf monitor’ group, but it seems that he was incorrect: work on lung and hemipenial structure, and on genetics, shows that they are closer to the ‘Pacific’ Euprepiosaurus group that includes the mangrove monitor complex. A close relationship between prasinoids and the mangrove monitor complex has been repeatedly supported in all of the recent studies on varanid phylogeny (Ast 2001, Collar et al. 2011, Conrad et al. 2012, Vidal et al. 2012, Pyron et al. 2013).

Hundreds of Madagascan reptiles and amphibians, found dead in a shipment to South Africa (but destined for the USA) during January 2014. At least some of the species here are CITES-listed and shouldn't have been exported at all.

One final issue requires mention here. All of the species here are highly sought after for the pet trade and, if you’re at all familiar with the monitors kept and bred in captivity, you’ll likely already have seen one or some of the taxa discussed here. Indeed, some were initially discovered only after they’d been imported to Europe for use in the pet trade. Habitat destruction due to logging, mining and so on all represent dangers to these forest-dwelling lizards (note that other monitors are being horrendously over-exploited for the skin trade), but the impact of commercial collecting shouldn’t be underestimated. There are some indications that uncontrolled collecting – even of CITES-listed species – represents a very real danger as goes the health of these populations (Koch et al. 2013), and if you think that people interested in the commercial collection and trade of tropical reptiles are operating within sensible, responsible boundaries, think again. Do check out the depressing articles on this issue here, here and here, and spread the word.

A tree monitor montage, images by Darren Naish.

For previous articles on varanids and other platynotan lizards, see…

Refs – -

Ast, J. C. 2001. Mitochondrial DNA evidence and evolution in Varanoidea (Squamata). Cladistics 17, 211-226.

Böhme, W. & H. J. Jacobs. 2001. Varanus macraei sp. n., eine neue Waranart der V. prasinus-Gruppe aus West Irian, Indonesien. Herpetofauana 23, 5-10.

- . & H. J. Jacobs. 2004. Varanus macraei. In Pianka, E. R., King, D. & R. A. King (eds) Varanoid Lizards of the World. Indiana University Press, Bloomington, pp. 212-214.

Collar, D. C., Schulte, J. A., & Losos, J. B. 2011. Evolution of extreme body size disparity in monitor lizards (Varanus). Evolution 65, 2664-2680.

Conrad, J. L., Balcarcel, A. M. & Mehling, C. M. 2012. Earliest example of a giant monitor lizard (Varanus, Varanidae, Squamata). PLoS ONE 7 (8), e41767

Czechura, G. V. 1980. The emerald monitor Varanus prasinus (Schlegel): an addition to the Australian mainland herpetofauna. Memoirs of the Queensland Museum 20, 103-109.

Eidenmüller, B. & Wicker, R. 2005. Eine weitere neue Waranart aus dem Varanus prasinus-Komplex von der Insel Misol, Indonesien. Sauria 27, 3-8.

Greene, H. W. 1986. Diet and arboreality in the Emerald Monitor, Varanus prasinus, with comments on the study of adaptation. Fieldiana 31, 1-12.

Irwin, S. 2004. Varanus keithhornei. In Pianka, E. R., King, D. & R. A. King (eds) Varanoid Lizards of the World. Indiana University Press, Bloomington, pp. 401-405.

Jacobs, H. J. 2003. A further new emerald tree monitor lizard of the Varanus prasinus species group from Waigeo, West Irian (Squamata: Sauria: Varanidae). Salamandra 39, 65-74.

- . 2004. Varanus kordensis. In Pianka, E. R., King, D. & R. A. King (eds) Varanoid Lizards of the World. Indiana University Press, Bloomington, pp. 205-207.

Kaiser, H., Crother, B. I., Kelly, C. M. R., Luiselli, L., O’Shea, M., Ota, H., Passos, P. Schleip, W. & Wüster, W. 2013. Best practices: in the 21st Century, taxonomic decisions in herpetology are acceptable only when supported by a body of evidence and published via peer-review. Herpetological Review 44, 8-23.

Kirschner, A., Müller, T. & Seufer, H. 1996. Faszination Warane. Kirschner & Seufr Verlag, Keltern-Weiler.

Koch, A., Ziegler, T., Böhme, W., Arida, E. & Auliya, M. 2013. Pressing Problems: distribution, threats, and conservation status of the monitor lizards (Varanidae: Varanus spp.) of Southeast Asia and the Indo-Australian Archipelago. Herpetological Conservation and Biology 8 (Monograph 3), 1-62.

Naish, D. 1998. All-new tree monitors – part 2. Mainly About Animals 38, 5-7.

Pyron, R. A., Burbrink, F. T. & Wiens, J. J. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 2013, 13:93 doi:10.1186/1471-2148-13-93

Sprackland, R. G. 1991. Taxonomic review of the Varanus prasinus group with descriptions of two new species. Memoirs of the Queensland Museum 30, 561-576.

- . 1994. Emerald monitors: lean, green and rarely seen. Reptiles June 1994, 16-23.

Vidal, N., Marin, J., Sassi, J., Battistuzzi, F. U., Donnellan, S., Fitch, A. J., Fry, B. G., Vonk, F. J., Rodriguez de la Vega, R. C., Couloux, A. & Hedges, S. B. 2012. Molecular evidence for an Asian origin of monitor lizards followed by Tertiary dispersals to Africa and Australasia. Biology Letters 8, 853-855.

Wells, R. W. & Wellington, C. R. 1985. A classification of the Amphibia and Reptilia of Australia.Australian Journal of Herpetology, Suppl. Ser. 1, 1-61.

Ziegler, T., Schmitz, A., Koch, A. & Böhme, W. 2007. A review of the subgenus Euprepiosaurus of Varanus (Squamata: Varanidae): morphological and molecular phylogeny, distribution and zoogeography, with an identification key for the members of the V. indicus and V. prasinus species groups. Zootaxa 1472, 1-28.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Jerzy v. 3.0. 5:20 am 02/17/2014

    Cool animals! It would be interesting to know, if these bright color variants are across the whole island, or there are also local races?

    Islands like Batanta, Waigeo and Misool are still extremely undeveloped and poorly connected to the outside world. People who tried to see birds of paradise and megapodes felt like nothing has changed since the time of Wallace. I am surprised that anything is exported out of there, and perhaps much of the islands are still safe for monitors.

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  2. 2. naishd 5:47 am 02/17/2014

    Interesting comment, thanks. One important thing to note: there are indications that animal traders move into a new area really quickly – basically, as soon as they hear that it’s a potentially rich source for interesting animals that will prove popular in the pet trade. This isn’t surprising when you see how much money they make from this trade (if local people are used as guides or middlemen, they of course only get paid pennies). This problem is so substantial that some herpetologists now deliberately withhold locality information on populations.

    I regard the trade in wild amphibians and reptiles (and other animals) as biopiracy – the countries and people that own this biological wealth are losing it at an unprecedented rate and are not seeing any of the benefits. The non-human animals concerned are not exactly getting a good deal, either, but that’s more obvious.

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  3. 3. Tayo Bethel 6:31 am 02/17/2014

    Part of the problem is thatthe local people are sometimes unaware of just how precious are biological resources. Here in the Bahamas, the pineyards are pretty much gone on New Providence along with their ecological diversity. The hutia is highly endangered and restricted to only two islands, yet very few of us have ever heard of it, let alone seen one.

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  4. 4. naishd 6:45 am 02/17/2014

    Tayo: and this is why ‘grassroots’ on-the-ground educational and conservation efforts are so important. I saw a documentary recently where an American or European worker was trying to combat illegal timber extraction in New Guinea. He was working with local people who were simply amazed to see the sale prices that their wood was being offered for in Europe and the USA — obviously, they had no idea. Clearly, more education of this sort is needed.

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  5. 5. almack 10:12 am 02/17/2014

    I had a wonderful show of a varanid trying to kill a snake in the canopy of my study area in Papua New Guinea. It was an epic struggle!

    In PNG we’ve found that varanids might be decreasing due to hunting for food by landowners. We are working with some landowners to devise more sustainable ways to harvest game.

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  6. 6. Heteromeles 11:41 am 02/17/2014

    Cool article, although the animal trade issue is depressing.

    I do know enough about the way the business works that I’m not surprised that entrepreneurs have learned to go in fast and clean out “new finds” of exotic reptiles and the like as fast as possible before enviros like me start making rules to keep them from making what they think is their proper profit. They know how fast the conservation community works, and they’ve simply figured out how to be more nimble.

    What I would suggest, for the scientists reading this, is that studying the microbiome and/or virome of exotic new species in the pet trade would be a REALLY GOOD research project. A lot of people couldn’t care less about conservation, but they wouldn’t want to die of some obscure and incurable tropical disease that they caught from their new exotic pet. SARS, for example. Because it’s a public health issue, I suspect there would be some funding for it too.

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  7. 7. Andreas Johansson 11:55 am 02/17/2014

    The Vogelkop Peninsula may be better known to some (it was to me) as the Bird’s Head Peninsula.

    (“Vogelkop” means bird’s head in Dutch.)

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  8. 8. Biology in Motion 1:49 pm 02/17/2014

    As an ex-zookeeper and long time reptile hobbyist (don’t worry, nothing wild-caught), I have far too many depressing stories about smuggled animals and wild caught “pets” dying slowly after reaching their target buyers. Slightly amusing was the group of twelve healthy monocled cobras (Naja kaouthia) that we confiscated from a crate labeled “melons”. At least that group of animals survived for many years in zoological collections (though would have been better in the wild).

    On a more fun note: we did have tree monitors in the Baltimore Zoo collection for many years. One fun anecdote is that they were the only monitors that would not use the tail as a whip when stressed. Instead, they always rolled their tails up like a clock spring and retreated.

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  9. 9. ectodysplasin 5:23 pm 02/17/2014


    I regard the trade in wild amphibians and reptiles (and other animals) as biopiracy – the countries and people that own this biological wealth are losing it at an unprecedented rate and are not seeing any of the benefits. The non-human animals concerned are not exactly getting a good deal, either, but that’s more obvious.

    In many cases, land development and exploitation for food is just as much a problem as the exotic animal trade. The developing world is, well, developing, which is a good thing for the people living there, but is a bad thing for biodiversity in general. Development in Europe and North America came at the cost of quite a lot of biodiversity, and both regions were relatively species-poor compared to more equatorial regions of Southeast Asia, Central America, etc.

    Removing large numbers of critically endangered animals from threatened habitats in order to set up captive breeding programs has been a standard approach for conservation of amphibians (e.g. Panamanian golden frogs, hellbenders, etc). Captive breeding programs in conservation institutes generally have limited funding and facilities space, though….certainly not enough to fund full breeding programs for all threatened species.

    So while I agree that there are some serious problems with this sort of exploitation of wild populations, it is probably the case that this does provide a captive breeding program of sorts for species which would otherwise be under extreme threat of extinction, and establishes care and breeding protocols at little to no expense to conservation funds.

    Finally, zoos do contribute to the captive reptile trade, by selling surplus offspring of captive reptiles to private buyers and buying exhibit reptiles from the wild and captive herp trade.

    The current situation is obviously untenable, but I think there’s more to be gained from working with commercial breeders etc than by trying to fight them.

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  10. 10. Tayo Bethel 5:39 pm 02/17/2014

    I’ve never heard of a turtle with a prehensile tail. It seems more than a little strange.

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  11. 11. naishd 3:23 am 02/18/2014

    Thanks to all for comments. ectodysplasin (comment # 9): I see your point… and I obviously appreciate that collecting for the pet trade is not the only problem affecting wild amphibians and reptiles, nor is it the major one in all places. However, the point remains that the collecting represents the equivalent of ecological strip-mining in some places, the level and scale of the trade representing a serious threat. Some of the individuals concerned illegally traffic large numbers of endangered species (classic example: Anson Wong), to the degree that viable wild populations are substantially threatened. You say that there might be “more to be gained from working with commercial breeders etc than by trying to fight them”; my point was less about ‘commercial breeders’ than unscrupulous, illegal collectors.

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  12. 12. darkgabi 5:39 am 02/18/2014

    i must agree with you on biopiracy, darren. coming from a land that suffers a lot with it, it is almost impossible for me to see any good point in this.

    the animals [not restricted to amphibians and reptiles but also affecting birds and small mammals] is that they are collected by people with no training in such biodiversity programmes. so it’s like illegal hunting. there are no rules as to when and how and which specimans can be collected without representing a serious threat to the local populations.

    usually animals are collected without these guidelines [also because no good study exist as to how it should be done, of course] and are kept and transported in conditions far from ideal, and many of them die in the way.. because it is illegal, they must be hidden. the collectors usually have no appreciation for the animals they are getting, they just want to sell. and i doubt many of these animals go to serious breeding programmes. also because it is illegal.

    it’s more or less the same with fossils. in brazil for instance it is illegal to collect and sell them since the 40s, but still researchers were buying crato fossils and describing them. nowadays, who will ever want to ppublish on a specimen that was taken illegally out of the country and that will give the researchers a huge headache? several pterosaurs and lizards are laying around north american and european collections in these situations.

    anyways, the official, serious breeding programmes, i think, will not accept such material. they end up in the private market.

    if it’d be better to make the market legal, it is another debate.. to which i have not yet a final opinion.

    pet trade is still strong not because developing countries are devloping.. just the opposite, it’s because they are still poor. developing economies will depend less on immediate ways of getting money, as people can find better rewarding jobs. well, it’s a long debate.

    i can’t understand the need of keeping such animals in the first place. especially if they are endangered [cuz if on one hand endangered species are captured by mistake, there is a market especifically for them. like for stolen paintings]

    oh well.

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  13. 13. Jerzy v. 3.0. 7:03 am 02/18/2014

    In one zoo I saw a possibility how exotic pet trade might be civilized. There was an advertisement of (small mammal) enthusiast society, which brought together zoo workers and private hobbyists interested in keeping and breeding small mammals.

    Another aspect of pet trade is that some hobbyists actually are the most knowledgeable experts in animals they keep. And zoos are chronically short of space and resources to keep large populations of endangered species. And it is very difficult to police the pet trade from uotside, especially after it was pushed into the grey market. So perhaps cooperation with the more responsible pet keepers and trying to influence the community from inside might work the best.

    Stil a question: what is the function of this blue color of varanids? It cannot be camouflage, and different species have strikingly different colors in reasonably similar environment. Maybe there is a social function here? Mate recognition, warning? Reminds me a little of races of callitrichid monkeys. I wanted to say poison arrow forgs, but small varanids appear relatively defenseless.

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  14. 14. ekocak 10:18 am 02/18/2014

    I would chime in and say broadly I agree that illegal collecting is a huge threat, and there do need to be better ways of handling this. However, I agree with some of the other commenters, in that there have been numerous times when hobbyist breeders end up being a huge resource. Also, every single firmly established pet trade species originated from a wild collected individual that was bred by often extremely devoted hobbyists. (Day geckos, for example). All that said, I don’t ever buy wild caught individuals and haven’t done so in many many years. Spent too much on the CBB animals to risk it anyways. Also, now Im super depressed about all the tree monitors I’m seeing posted on FB reptile sales sites.

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  15. 15. Tayo Bethel 8:02 pm 02/18/2014

    The problem, as Dr. Naish says, isn’t irresponsible breeders but irresponsible traders, So the question should be not how to work with the breeders–that would be the easy part. The problem is how to make irresponsible traders into responsible ones. Most of these people are poor and regard animals as no more than a ready supply of meat and money. Do we think of the comfort of a stack of cans in the cupboard? Perhaps the only way to deal with this problem isto legalize the trade and apply very strict limits to what and what how much can be taken.

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  16. 16. darkgabi 5:29 am 02/19/2014

    it works nicely on paper, but in reality it’s something else. i know that making it illegal requires an governmental apparatus for inspection to avoid the trade – which could then be used for controlling what’s leaving instead. but then why would you have such a market to start with? i dunno numbers, but i doubt “responsible breeders” make the bulk of the demand. it is a problem for all sorts of pets to be abandoned. florida has suffered a lot from invasive crocs [!] and snakes [!!] coming from the pet market, and rabbits are a pleague basically everywhere.

    maybe the whole thing would work better in two ways: making it legal and applying strict rules but also trying to discourage this market. i really can’t see a reason for someone wanting to have exotic pets at home anyways.. but if someone really likes it, having some lizard or spider from his/her area would be less damaging in general, from transportation to commerce to alien species issues.

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  17. 17. ekocak 8:41 am 02/19/2014

    @darkgabi re: exotics

    Keeping exotics was a big part of what fueled my early interest in biology and know others with similar stories. I agree that the trade is harmful, but I don’t think an outright ban is the answer.

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  18. 18. Tayo Bethel 9:18 am 02/19/2014

    As long as there’s a demand for exotic pets, there will be people willing to make money by illegal or legal trading. Enforcing laws in practice is difficult everywhere. Since the traders see these exotic species as no more than financial resources, it might be better to make them aware of just what would happen to their finances if they destroy the resources on which they are depending for their financial gains.

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  19. 19. Heteromeles 10:28 am 02/19/2014

    This problem crops up all over the place. In California, where I live, most of the houses lost to wildfires are in the suburbs, at the “Wildland-Urban Interface” (WUI), the interface between “civilization” and “nature.” In California, the WUI also contains a lot of rare and endangered species, particularly along the coast. Every park is hemmed in by developments, and a fire that starts in a park can burn down homes.

    There are two proposed solutions: one is that the “brush” in the WUI should be destroyed so that it no longer poses a danger to homes. The other is that no one should live in the WUI.

    Neither of these proposals is workable. The biggest problem is that most ecologists and environmentalists grew up in the WUI, and more than a few of them were off playing with fire in the brush. They just didn’t cause a conflagration.

    We’ve got the analogous problem with the exotic pets trade. Even assuming it could be outlawed by making people forget about the possibility of such pets and such animals, what would that do to conservation efforts? I know for a fact that apartment dwellers are dangerously clueless about WUI issues, just as non-biologist/non-pet owners are generally clueless about conservation issues. What happens when you switch from greed to cluelessness as the basis for environmental management?

    It’s not a simple problem. Law enforcement is necessary, not to eliminate the trade, but to keep it within reasonable bounds. When that doesn’t happen, you have things like the 19th Century trade in passenger pigeon meat. Education is also critical, both on the supply side and on the demand side, both to stem the trade and to make it more humane where it can’t be eliminated. Finally, I’d say that “corruption” is necessary, because you can get some of the best conservationists when you “corrupt” the black marketeers, ardent hobbyists, and goof-offs who’d rather be outdoors into working for environmental issues instead of for their own greed. But none of these is a perfect answer.

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  20. 20. ectodysplasin 12:22 pm 02/19/2014


    it is a problem for all sorts of pets to be abandoned. florida has suffered a lot from invasive crocs [!] and snakes [!!] coming from the pet market, and rabbits are a pleague basically everywhere.

    Introduction of rabbits was likely more of a meat/furs issue than an escaped pet issue. Similarly, the crocodile populations, and probably some of the snake populations, are associated with the leather trade rather than the exotic pet trade. Other exotic introductions (e.g. Tilapia in Florida, snakeheads in eastern North America, common carp in North America, grass carp in the Mississippi watershed, etc) are associated with food production, and not the pet trade.

    In terms of sheer environmental damage, feral dogs and feral cats are far, far worse for the environment and for endangered species. Add mongoose, goats, and ferrets to that list, too….none of which were introduced as escaped pets per se (and some of which were introduced intentionally). Free-ranging cattle are an utter nightmare. And chytrid was probably spread via research populations of Xenopus.

    This isn’t to downplay the role of escaped pets in the ongoing biodiversity issues (lionfish are a total disaster, for example), but to point out that we’re really, really bad about keeping domestic species from impacting wild populations of plants and animals.

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  21. 21. darkgabi 12:45 pm 02/19/2014

    thanx for the list, jason, i am well aware of that [although i read somewhere that crocs and snakes in florida were indeed from the pet market, but anyways]. my main point is actually the impact on original populations. for sure it isn’t a simple equation.

    maybe you’re right, heteromeles.. fiscalization and education should work better. but a lack of motivation should also come to play – something like they’re trying to do with smoking, banning propagandas and such. not comparing the impact of smoking and exotic pet trade, of course, but you get it. you don’t need to stimulate certain things, that’s all. i am usually against prohibition politics [like drugs] cuz they mostly don’t work, but in this case i’m still not sure.. i’m sincerely torn, like regarding fossils.

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  22. 22. ectodysplasin 12:46 pm 02/19/2014


    However, the point remains that the collecting represents the equivalent of ecological strip-mining in some places, the level and scale of the trade representing a serious threat. Some of the individuals concerned illegally traffic large numbers of endangered species (classic example: Anson Wong), to the degree that viable wild populations are substantially threatened. You say that there might be “more to be gained from working with commercial breeders etc than by trying to fight them”; my point was less about ‘commercial breeders’ than unscrupulous, illegal collectors.

    Yes. There are definitely unscrupulous collectors, and there are smugglers who do some pretty scummy stuff as well. But removal of entire wild populations from the wild has been a long-term practice of conservationists too. You won’t see Panamanian golden frogs in Panama, but you can see them in Denver, Colorado, where there’s a breeding program. We could say the same thing about the Lake Titicaca frog, and various other animals. Is it still strip-mining a country’s biological resources if it’s ostensibly for conservation purposes?

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  23. 23. ectodysplasin 1:02 pm 02/19/2014


    my main point is actually the impact on original populations.

    Well, with the examples of nile crocodiles, spectacled caimans, burmese pythons, and nile monitors in Florida, the original populations of these animals all seem to be doing okay.

    With respect to some of the more at-risk populations, this is obviously not the case, but that risk extends beyond simple collection pressure. With amphibians especially, every population is at risk of devastating chytrid infections. With reptiles, climate change and development are major threats, as is another emerging communicable disease (inclusion body disease). So, a lot of these at-risk species are not going to be present in the wild in 20 years, period. They might be present in zoo breeding programs. They might be present in private animal collections. But this is dependent upon development of breeding protocols, establishment of captive breeding populations, etc. Zoos only have so much space and money, and conservation organizations generally put money towards charismatic megafauna, whereas speciose clades full of vulnerable taxa will not receive that attention.

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  24. 24. darkgabi 1:29 pm 02/19/2014

    hum. maybe you have a point…

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  25. 25. ectodysplasin 4:43 pm 02/19/2014

    I wish I didn’t, because I do recognize the ethical issues involved, especially with respect to the imperialism and colonialism issues. The problem is that this is a resource issue, and resources for conservation are not growing at the same rate that need for conservation resources is increasing.

    If we look at conservation of animals like, say, axolotls, we can see that captive breeding programs associated with purposes beyond simple conservation have benefits. Even if axolotls go extinct in the wild, we’re never going to lose the axolotl.

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  26. 26. naishd 4:43 am 02/21/2014

    Thanks for further comments, everyone. I just wanted to briefly address ectodysplasin’s comment # 22, in which the suggestion is made that the ‘strip-mining’ practises of illegal collectors and dealers is similar to the removal of animals by conservationists. I don’t think this comparison is valid. Firstly, conservation efforts that involve the removal of wild animals generally (perhaps, these days, universally) include, or are led by, local conservationists and biologists (example: this project involving Panamanian golden frogs). Secondly, the animals are not always or generally removed from the country of origin – conservation centres are established locally (example: there is lots of info online about the Amphibian Rescue and Conservation Project in Panama). Thirdly, there is a clear interest in maintaining the cultural links local people have with their native amphibians and reptiles (in encouraging so-called grassroots conservation interest), and in getting the animals back into the wild at some point in the future.

    In short, I can’t see the motives or methods of these conservation efforts as being at all similar to the nefarious, greed-driven collecting practised by unethical collectors and traders.

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  27. 27. ectodysplasin 9:45 pm 02/22/2014


    I’m not saying these are equivalent. I’m saying that the impact on wild populations is the same i.e. total extirpation or extinction in the wild. And honestly, as much as lip service is given towards the idea of breeding these animals so they can be reintroduced into the wild, that is generally not what happens.

    So, the issue now becomes what we want to do with these animals if we’re resigned to keeping them only in captivity. You’ve mentioned a few possible reasons why zoos and conservation programs might be superior to the private trade: keeping the animals in cultural context, maintaining the possibility of reintroduction, etc. I don’t disagree with you on these points, but there are a few additional considerations here.

    First, captive populations in private hands do not prevent captive populations from being in zoos, either local or international. In fact, in many cases there is some flow of genes from zoo stock into private trade and vice versa. This is especially the case with amphibians and reptiles. Zoos do not generally acquire mammals from private individuals, but they often do acquire reptiles and amphibians from the private captive reptile trade. Similarly, surplus mammals are not generally sold to private individuals (see: the discussion of the recent giraffe fiasco) but surplus reptiles are sold by zoos to private buyers. This is not the case for threatened/endangered/protected species, but it does still happen.

    Second, while we can talk up the importance of local conservation programs, it’s worth remembering that western conservation priorities are not necessarily universal. China, for example, puts huge amounts of money towards giant panda conservation, but had no problem with letting the river dolphin go extinct, for a combination of economic and cultural reasons. This is perhaps an extreme example, but I have to wonder how much money and conservation effort many countries are really interested in putting towards conserving dozens of essentially identical species of lizards, or snakes, or frogs, especially when these countries often have much more immediate economic and humanitarian concerns.

    Ultimately, I don’t have answers here, and I’m not really arguing for any particular way forward. My point of bringing up conservation programs that involve wholesale removal of wild populations is not to say that wholesale removal of wild populations is a good thing, but rather to point out that, at least in some cases, we’ve abandoned the pretense of trying to keep these animals alive in their natural context, and are now simply trying to keep them alive wherever we can. If this is now the conservation modus operandi, then we have to ask whether motive is important, or whether we’ve reached the point where establishment of captive populations of these animals is more important than who’s doing it.

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  28. 28. naishd 6:30 am 02/23/2014

    We’re not in disagreement here, and I appreciate your points. Conservation efforts, the thinking behind them, and the way they’ll pan out in future are not perfect; problems abound, for sure. But none of this changes the fact that unethical dealers and traders are a major problem: they are not friends of conservation, of the preservation of biodiversity, or of the local cultural, ecological or financial value of the animals themselves. And that’s why we started this discussion.

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  29. 29. ectodysplasin 2:04 pm 02/23/2014


    But none of this changes the fact that unethical dealers and traders are a major problem:

    No disagreement there. I just disagree that all dealers and traders are unethical, and that the captive trade is necessarily a different beast from zoo-led conservation efforts.

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