American Herping: A Guide to Reptiles and Amphibians in US Zoos

Not in the survey, no - though I've seen this species in a reptile store just this year so still present in the private sector to some degree.

 

Nice - my understanding is both are hanging on in the private trade, they're just not very common. Afaik the cordylid can be mixed with several other Madagascar/East African reptiles from drier habitats, not sure why they haven't gotten more popularity.

 

Another smaller post today, but the next half dozen or so (this week and next) will be longer as I try to cover some large and well-known families succinctly.

Family Gerrhosauridae – Plated and Girdled Lizards

"Wait, didn't we just do girdled lizards?" Yes, this is another closely related family of African lizards - and while some members of this family are called "girdled" also, the two most common species are more frequently referred to as plated lizards.

Sudan Plated Lizard (Broadleysaurus major) – Prevalent
Giant Plated Lizard (Matabosaurus validus) – Prevalent

Most "plated lizards" in American collections belong to these two species. Both are larger than other members of the families, with the larger one (Giant) being over 2 ft in length. They are also both flat, thick-bodied lizards with notably plated scales. Colorwise, the Sudan tends to be more of a dull, uniform brown or gray; the Giant is a little variable in color but is more often multi-toned, sometimes with a tinge of red on the undercarriage. Sudans are slightly more common in zoos here – they are predominant in the private trade as well as unaccredited facilities – while Giants are found in several major zoos.


Sudan Plated Lizards (B. major) / Taken by @ISAO at the Taipei Zoo (Taiwan)


Giant Plated Lizard (M. validus) / Taken by @OkapiFan at the North Carolina Zoo

In addition to these two, the San Diego Zoo and at least a couple reptile specialist zoos hold the Yellow-throated Plated Lizard (Gerrhosaurus marginatus), a more slender species.


Taken by @ThylacineAlive at the San Diego Zoo

Zonosaurus – Madagascar Girdled Lizards
Status in US Zoos: Uncommon

Referred to as either girdled or plated lizards, these smaller island-based gerrhosaurids are seen less frequently than their large mainland relatives. Five species were found in the survey, most of which were only found once or twice.

Karsten’s Girdled Lizard (Z. karsteni)
Madagascar Girdled Lizard (Z. madagascariensis)
Southeastern Girdled Lizard (Z. maximus)
Ornate Girdled Lizard (Z. ornatus)
Four-lined Girdled Lizard (Z. quadrilineatus)


Genus example photo / Taken by @ThylacineAlive at the Bronx Zoo

 

Family Scincidae – Skinks

Over 1,500 species of skink are found across the world in a variety of habitats, and though they vary in shape and size there are two mostly consistent features: tiny legs, no neck. Many of them are among the lizards who can snap off and regenerate their tails to escape predators – but don’t try this at home please!

The survey found 23 species of skink in American zoos. Compared to many other groups, the holdings it found were very lopsided; over 60% of the ~150 holdings came from just 3 species. Today I’ll cover the most common ones, then the following post will explore some more rarely seen species.

Prehensile-tailed Skink (Corucia zebrata) – Abundant

Also called Monkey-tailed Skink or Solomon Islands Skink, this was the second-most common lizard species in the survey. It is largely found in AZA zoos (both large and small), where it is managed as a breeding program. Native to tropical islands off the coast of New Guinea, this arboreal skink is the largest in the world at over 2.5 ft in length. Their scales are green, ranging from dark to a dull pale speckled with black or brown. They are also one of the few social reptiles, forming bonded pairs and an unusual reptilian social group called a “circulus”.


Taken by @Lucas Lang at the Central Park Zoo

Blue-tongued Skinks (Tiliqua spp) – Very Common to Abundant

An iconic Australian reptile, popular in zoos both for exhibit and as an educational/ambassador animal. Common in the pet trade due to their straightforward care and docile nature, blue-tongues are gentle herbivores that use their weirdly-colored tongue to freak out predators. This is a good call, because their stubby little legs can’t outrun even the Outback’s mediocre hunters (a joke – I wouldn’t be surprised if they can actually move quite fast!)

Also found on New Guinea and offshore islands, there are multiple species and subspecies of blue-tongued skink. Most found in the survey belong to the Common Blue-tongued Skink, T. scincoides; however, some are the Indonesian species T. gigas and there was one (now seemingly gone) record of an uncategorized type called Irian Jaya. While the pet trade seems to be mainly island subspecies like Tanimbar, Merauke, and Kei Island, several zoo animals in the States belong to mainland Australian subspecies – including at least 4 holders of Northern (T. s. intermedia) and one holder of Eastern (T. s. scincoides).



Taken at the North Carolina Zoo by @Andrew_NZP (above) and @OkapiFan (below)

Shingleback Skink (Tiliqua rugosa) – Prevalent

Actually one of the blue-tongued skinks – if one opens its mouth, you’ll see I’m right – but categorized separately as it’s pretty distinctive. Its thick stubby tail is good for fat storage, but is even more useful in that it creates the illusion of a two-headed animal – not a predator’s first choice of prey! They’re also pretty heavily scaled. Basically, they’re designed to survive anything. These are mostly found in several major zoos, although a few reptile specialist places have them also.


Taken by @jayjds2 at the Philadelphia Zoo

 

Ah, the blue-tongued skink! One of three taxa that are so needlessly complicated to tell apart that I keep track of as a species complex on my lifelist, with the others being galapagos tortoises and vervet monkeys.

 

Family Scincidae (Part 2/2)

As promised, we'll finish up the week with more skinks.

One thing I accidentally left off the previous post: the Dallas Zoo has a third species of blue-tongued skink, the Centralian species (Tiliqua multifasciata). They are the only holder I'm aware of.

Emerald Tree Skink (Lamprolepis smaragdina) – Uncommon

An arboreal skink from the Philippines. It is only one-third the size of a Prehensile-tailed Skink and is a bright, almost neon green. This species seems to be increasing in popularity; most references to them on the forum are fairly recent, and all but one of the EU holdings began in 2018 or later.


Taken at the Brookfield Zoo by @Pleistohorse

Red-eyed Crocodile Skink (Tribolonotus gracilis) – Uncommon

A very distinctive-looking skink from New Guinea, with rows of spikes along the back like a crocodile along with a well-defined head (rather than the nub with eyes other skinks got stuck with). These are another species that seem to cycle in and out of zoos quickly, making it difficult to know who has them at any given time.


Taken at the Singapore Zoo by @Zooish

Egernia (Spiny-tailed Skinks)
Status in US Zoos: Prevalent

A group of mid-sized Australian skinks. They are short and stubby lizards with varying degrees of plated or spiny scales, and are most commonly found in the hot deserts of the continent’s interior. The survey found half a dozen species, none of which were found in more than a few zoos each:

Cunningham’s Skink (E. cunninghami)
Pygmy Spiny-tailed Skink (E. depressa)
Eastern Pilbara Skink (E. epsisolus)
Hosmer’s Skink (E. hosmeri)
King's Skink (E. kingii)
Gidgee Skink or Stokes’s Skink (E. stokesii)


Hosmer's Skink (E. hosmeri)
Taken at the Philadelphia Zoo by @jayjds2

Plestiodon
Status in US Zoos: Prevalent

Small, fast and shiny. These temperate skinks can be found scampering across sidewalks and forest floors in East Asia and North America. Four species were found in the survey, all native to the US. They are fairly common in the wild, but are one of the less common natives seen in captivity; they are most often found in nature centers or other locally-focused collections.

Five-lined Skink (P. fasciatus)
Broad-headed Skink (P. laticeps)
Great Plains Skink (P. obsoletus)
Western Skink (P. skiltonianus)


Wild Plestiodon skink at the Jacksonville Zoo; taken by @MinxFox

Other skinks in survey or added in post (all Rare):

Madagascar Giant Water Skink (Amphiglossus reticulatus)
Land Mullet/Major Skink (Bellatorias sp.)
Black Emo Skink (Emoia nigra)
Berber or Schneider’s Skink (Eumeces schneiderii)
Fire Skink (Lepidothyris fernandi)
Peters's Banded Skink (Scincopus fasciatus)
Sandfish Skink (Scincus scincus)
Two-colored Skink (Trachylepis dichroma)
Sulawesi Water Skink (Tropidophorus baconi)

 

Family Teiidae – Tegus and Whiptails

Fork-tongued predators from the Americas, this group is somewhat famous for having several “female-only” species that reproduce through parthenogenesis. The largest members of the family – the tegus of South America – are also well-known as sociable pet lizards. The survey found 7 species from this family - four tegus and three smaller species.

Northern Caiman Lizard (Dracaena guianensis)
Status in US Zoos: (AZA) Common to Very Common (non-AZA) Rare

These “water tegus” are popular for tropic houses and Amazon-themed tanks, where they like to perch on branches above the water. The best exhibits give them plenty to dive into, as they are excellent swimmers that feed on aquatic snails in the wild. Though they are present in the private sector to a limited degree, it is in major AZA zoos that you are most likely to find these lizards; they seem to be quite rare in unaccredited facilities.


Taken at the Abilene Zoo by @Coelacanth18

Salvator
Argentine Black-and-White Tegu (Salvator merianae) – Prevalent to Common
Red Tegu (Salvator rufescens) – Uncommon

Other than the caiman lizard, nearly all other tegus seen in US zoos belong to the two species most common in the pet trade. Opportunistic omnivores, these large lizards will feed on just about anything – especially eggs. This has made them a problem in Florida, as well as states unfortunate enough to border Pantropica – the species potentially endangers sea turtle and alligator nests with its ovivorous habits. Their intelligence and tolerance to different climates also bodes poorly for limiting future expansion. Meanwhile, in South America they are harvested in large numbers for the leather trade.

Unlike caiman lizards, these are more likely to be found in smaller and/or unaccredited zoos – likely due to their widespread availability in the pet trade.


Argentine Black-and-White Tegu (S. merianae)
Taken at Out of Africa Wildlife Park (Arizona) by @snowleopard


Red Tegu (S. rufescens)
Taken at the Tulsa Zoo by @keith8404

Desert Grassland Whiptail (Aspidoscelis uniparens) – Uncommon

A small slender lizard from the Southwestern United States, and one of the all-female species mentioned earlier.


Taken at the Toledo Zoo by @birdsandbats

Other species found in survey (all Rare):
Blue Ameiva (Ameiva sp.)
Common Tegu (Tupinambis teguixin)
Aruba Whiptail (Cnemidophorus arubensis) – only one holding, not reported since 2018

 

Note some zoos (particularly some accredited ones) have tegu ambassador animals that aren't on exhibit. This isn't the only species on this list that's a common ambassador, but since these lizards aren't as ubiquitous as, say, bearded dragons or leopard geckos, I figured I'd mention it.

 

MODS in Fort Lauderdale, FL keeps or kept until recently Common Ameiva (Ameiva ameiva).

 

That's the same as the "Blue Ameiva" listed at the end. The Ameiva ameiva complex is a taxonomic mess right now.

 

Shedd Aquarium had ameiva back in 2018 (they no longer do) which was how the genus showed up in the survey. I think the list I used as a source called them "Blue Ameiva" but naming inconsistencies and recent splits did lead me to throw a blanket genus over that listing. Having seen them for sale before I was vaguely aware they were still around, but it's good to know about another facility who had them recently!

 

Shedd should still have the species.

 

Yes, you're right. I missed them in the 2022 list, probably because "ameiva" always sounds like the name of a fish to me - and there's a lot of fish to skim over in Shedd species lists

Family Varanidae – Monitor Lizards
Genus Varanus

Few lizards bring in crowds like a good monitor lizard! These large, intelligent, active reptiles are fascinating to watch. Carnivorous lizards from the Old World, there are about 80 species around the world, about 30 of which are kept in American collections. All species belong to the one genus Varanus, so for the sake of organization I will group them by shared characteristics. This last major lizard group will take us through the rest of the week.

Tree Monitors (subgenus Hapturosaurus)

These are some of the most popular species in captivity. Highly intelligent, many zoos will give them food puzzles to solve. The tree monitors come from Southeast Asia and New Guinea.

Emerald Tree Monitor (V. prasinus) – Common

From the main island of New Guinea, one of the two more common tree monitors in American zoos. While none of the tree monitors were found much outside the AZA, this seems to be the most common in reptile specialist zoos (almost none of which are AZA accredited).


Taken at the San Diego Zoo by @RockTheThought

Black Tree Monitor (V. beccarii) – Common

From the Aru Islands, one of the two more common tree monitors in American zoos. This is an AZA breeding program, and at least two zoos (San Diego and Oklahoma City) have bred them in the past couple years.


Taken at the Oakland Zoo by @TheEthiopianWolf03

Blue-spotted Tree Monitor (V. macraei) – Prevalent

Found on a single island off the west coast of New Guinea, and unfortunately an endangered species. Similar in size to the previous two, macraei is not as common as Green or Black but is still found in several zoos here.


Taken at the Bronx Zoo by @ThylacineAlive

Other Arboreal Monitors

Crocodile Monitor (V. salvadorii) – Prevalent

At 8 ft long, this is one of the largest lizards on the planet. Dark with yellow spots and a very long tail that often curls at the end, it is found in the coastal swamps and jungles of New Guinea. This is one of the more difficult species both to care for and breed in captivity, although a small handful have been successful over the past 30 years – most recently Dallas Zoo in 2022, as well as Honolulu Zoo in 2019.


Taken at Zoo Miami by @Maguari

Gray’s Monitor (V. olivaceus) – Uncommon

A Philippine tree monitor that not long ago was quite rare here, but has been spreading to more American zoos lately thanks to breeding successes at the Los Angeles Zoo. In my experience this is an extremely active monitor, so they make for a great reptile display. The Gray’s is also unusual among monitors in that it mainly eats fruit rather than meat.


Taken at the Los Angeles Zoo by @Blackduiker

Other arboreal monitors in survey (both Rare):
Two rare species that look similar to Emerald Tree Monitors (and were once considered the same species) are also present:

Reisinger’s Tree Monitor (or Yellow Tree Monitor) (V. reisingeri)
Biak Tree Monitor (V. kordensis)

 

Continuing with monitors again! A couple things I forgot to mention in yesterday's post:

- There is a species I missed from Teiidae, which has been reported from a couple of zoos in the past few months - the Rainbow Whiptail (Cnemidophorus lemniscatus)

- While these posts on monitors focus on my survey findings for American collections, @vogelcommando has a thread on monitor lizards in captivity globally that goes into more detail about international holdings and captive breeding history - so if you're interested in a deeper dive the thread is here: Monitor-lizards in captivity

African Monitors

Rock Monitor (V. albigularis) – Uncommon

This ground-dwelling species from the African savanna can be easily identified by its bulbous snout. Most zoos sign these as either White-throated Monitor or Black-throated Monitor, its two subspecies; however, multiple zoos seem to have signed their animals as both at different points in time, so I have no idea what is actually present. Despite the subspecies names being exact opposites, they are indeed the same species.


Taken at the Kansas City Zoo by @KCZooFan

Savannah Monitor (V. exanthematicus) – Uncommon

One of the more common species in the pet trade (representing nearly half of international trade), and (in the survey at least) almost exclusively held by unaccredited zoos. It is a smaller but sturdily built species. Most specimens are actually wild-caught, as breeding has not proved very successful in most cases (though the wide availability of wild-caught animals may also be a motivational/financial factor in that).


Taken at the Portland Aquarium (now closed) by @snowleopard

Nile Monitor (V. niloticus) – Uncommon

Another species that is more common in unaccredited zoos and in the pet trade, despite having a reputation for aggression. Found all over the African continent, these can grow to be one of the largest monitor species. They are highly adapted to aquatic life, though they are also adept climbers and fast runners. They currently run amok across the state of Minnesota. Sorry, did I say Minnesota? I meant Florida.


Taken at the Honolulu Zoo by @Blackduiker

Water Monitors

Asian Water Monitor (V. salvator) – Prevalent

With adults usually getting to 5 or 6 ft in length – but the largest recorded was 10.5 ft – these are big lizards. True to their name, they are found throughout the wetlands of tropical Asia, particularly in mangrove swamps. They are also very tolerant of human activity; they are commonly found in urban canals and rice paddies. They’ll eat just about any living or dead animal smaller than them, from frogs and rats to crabs and turtle eggs… even cats and dogs! In addition to being collected as pets, millions have been harvested for leather.

These are one of the more common monitors in unaccredited and reptile specialist zoos, although a few major zoos exhibit them as well.


Taken at the Santa Barbara Zoo by @ThylacineAlive

Mertens’ Water Monitor (V. mertensi) – Prevalent

Easily distinguished from V. salvator in at least two ways: 1) it’s a lot smaller (about half the size, at ~3 ft) and 2) it is much more uniform in its brown-to-black coloration compared to the spotting and banding usually seen on salvator. This endangered species is found in the wetlands and rivers of northern Australia. These are more likely to be seen in major accredited zoos, but they’re also around in other zoo facilities and in the private trade.

Even though there are some pretty good American photos (including a few underwater shots), a recent photo I found from Steve Irwin’s zoo in Australia was too good not to use!


Taken at the Australia Zoo by @WhistlingKite24

 

While on the topic of Varanids, one thing worth mentioning is that the Bronx Zoo is an excellent place to go in order to see this fascinating family of lizards. On my recent visit, I saw eight different species of monitor lizard, five of which I've never seen at other zoos! Many of the monitor lizard exhibits at Bronx are also excellent, with the monitor exhibits in Zoo Center being one of my favorite spots in the whole zoo (which surprised me since it's not often talked about on here).

 

Monitor Lizards, Part 3 of 3

Spiny-tailed Monitor (Varanus acanthurus) – Prevalent

A very small monitor species that reaches up to 2 ft in length. Found in the Australian Outback, these are one of the most common monitors to be kept as pets. The majority of their diet consists of arthropods.

I’ve dubbed this lizard the Puma concolor of reptiles, as it is referred to by an absurd number of names: Spiny-tailed appears to be the most common, but you may also see Dwarf, Ackie, Ackie’s Dwarf, or Ridge-tailed.


Taken at the Audubon Zoo (New Orleans) by @snowleopard

Perentie (V. giganteus) – Uncommon

A large monitor that also hails from the deserts of Down Under. A powerful digger, these are shy animals but when cornered can deliver a nasty bite thanks to slightly venomous salivary secretions (and sharp teeth). This seems to be one of the better-known rare herps; Dallas, Los Angeles and Omaha all display Perentie currently, while Reptile Gardens in South Dakota and Iguanaland in Florida - two of the largest reptile zoos in the country - also hold the species. The Dallas Zoo bred them in 2018, a repeat for them as they were also the first ones outside Australia to breed them over 20 years ago; the Omaha Zoo became the second US zoo to breed them just this March. There are currently none in Europe, but they are common in Australian zoos.


Taken at the Dallas Zoo by @MagicYoung

Komodo Dragon (V. komodoensis)
Status in US Zoos: Abundant (AZA); Rare outside AZA

The big one! Komodo Dragons are one of the few true reptilian “superstar” species, a big crowd-pleaser that some zoos dedicate entire complexes to. At a max size of 10 feet and weight of 150 lbs, this is the largest lizard in the world – so large that they hunt deer on their native Indonesian islands. Komodo Dragons incubate their eggs by burying them in the volcanic soil and then leaving; this is also a species famous for parthenogenesis, meaning that females have laid eggs without ever encountering a male. While the huge adults live on the ground, the smaller and more agile hatchlings and juveniles most of their time in the trees to avoid their cannibalistic elders. Their saliva contains anticoagulants, which assists their prey in bleeding to death after a bite.

Originally rare in zoos outside Indonesia due to breeding difficulties and frequent illness in wild-caught animals, the first successful captive breeding occurred in 1992 as a joint project between George Mason University and the Smithsonian National Zoo. In the past 30 years breeding efforts have improved dramatically, and now most major zoos in the United States either have them or are planning to acquire them in the next few years. They are slightly more common here than in Europe, and major European zoos such as Frankfurt, Leipzig, Prague and Chester have acquired captive-bred animals from the United States over the past two decades. At least four US zoos – Bronx, San Antonio, Chattanooga and Knoxville – have produced over 20 hatchlings since 2020 alone.


Adult; taken at the Memphis Zoo by @Coelacanth18


Juvenile; taken at the Smithsonian National Zoo by @Andrew_NZP

Other monitor lizards in survey:

Uncommon
Argus Monitor (or Yellow-spotted Monitor) (Varanus panoptes)

Rare
Cuming’s Water Monitor (V. cumingi)
Blue-tailed Monitor (V. doreanus)
Dumeril’s Monitor (V. dumerilii)
Yellow Monitor (V. flavescens)
Kimberley Rock Monitor (V. glauerti)
Mangrove Monitor (V. indicus)
Quince Monitor (V. melinus)
Clouded Monitor (V. nebulosus)
Large-scaled Water Monitor (V. nuchalis)
Pilbara Monitor (V. pilbarensis)
Black Roughneck Monitor (V. rudicollis)
Solomon Island Spiny Monitor (V. spinulosus)
Black-headed Monitor (V. tristis)
Lace Monitor (V. varius)

 

Question: Are there any holders other than Buffalo of this species? It's one of the coolest species in Buffalo's reptile house, in my opinion, and one that I think could make an engaging display animal at any zoo, but I've never seen it or heard of it being kept in any other facilities.

 

What are the non-AZA places with Komodos?

 

Pittsburgh, for one (yes, I know, they're a special case)

 

None that I've come across. The only other reference to one in the forum or gallery is a photo from the Boulder Ridge Wild Animal Park (an unaccredited zoo in Michigan) but that was 10 years ago.

I haven't seen the species myself (never been to Buffalo) and don't know much about it; what features do you think lend it to being an engaging display animal? I'm not sure why it isn't more common, besides the fact that most monitors just aren't held in high numbers.

Setting aside Pittsburgh, also Metro Richmond and Reptile Gardens (mentioned in the same post as having Perentie). Montgomery Zoo has plans to add Komodo dragons to their new reptile house once it opens; TBD on that I guess.

At the time I wrote the post there was another unaccredited facility (not in the survey) that also had them - a rather obscure place in the Chicago suburbs called the Wildlife Discovery Center; it closed in March of this year, I'm not sure where their dragon(s) went. I don't know exactly what the nature of the facility was... sort of half nature center, half reptile zoo? Rob Carmichael was the curator/director of the place, and is a member of the IUCN Crocodile Specialist group; the center was raising Orinoco crocodiles it acquired from either DWA or Gladys Porter, so it at least had some involvement with AZA facilities.