That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

As part of my work for the Bronx Zoo’s reptile department, I once assisted in the rehabilitation and placement of nearly 10,000 Asian turtles confiscated from southern China and forwarded to Florida (please see article linked below). Included among the Spotted Pond Turtles, Painted Terrapins, Spiny Turtles were a great many Asian Leaf Turtles (Cyclemys dentata). This impressive turtle had been a great favorite of mine ever since we first crossed paths decades earlier, during my time working for NYC animal importers, and later on in zoo collections. Like many Southeast Asian turtles, this species is in severe decline, and has been extirpated from large portions of its range. Fortunately, Asian Leaf Turtles fare well in the hands of experienced owners. Those interested in turtle conservation can find no more worthwhile species to work with…and, as a bonus, they are extremely interesting and responsive!

 

Range and Habitat

The Asian Leaf Turtle’s range extends from eastern India south and east through Myanmar, Thailand and Malaysia to the Philippines. Although the range is large, local extinctions are commonplace. Collection for the food and medicinal trades has devastated wild populations, so please be sure to purchase only captive-bred individuals.

 

It is found along shallow streams, ponds and marshy areas, and in nearby thickets. Youngsters spend most of their time in water, while adults forage on land as well.

Description

The carapace, which is almost round in outline and somewhat domed, can be olive, tan, black, brown or deep mahogany in color; thin, reddish-orange stripes mark the head and neck. The edge of the carapace bears spine-like projections, which are much more distinct in juveniles than adults.

 

Adults average 8-10 inches in length.

 

Captive Temperament

Although initially shy, Asian Leaf Turtles adjust to captivity quickly, and soon learn to feed from the hand. Most owners describe them as “amazingly-responsive,” and longevities in excess of 30 years have been recorded.

 

Males often harass females with mating attempts, and may stress or bite them in the process.  In addition, males cannot be kept together, as they will usually fight.

 

The Terrarium

Hatchlings are highly aquatic, but rather poor swimmers. The water in a hatchling’s aquarium should be of a depth that allows the turtle to breath at the surface without needing to swim, i.e. 1-2 inches. The aquarium should be equipped with an easily-accessed basking site, UVB bulb, water heater, filter, and floating plastic or live plants under which the shy youngsters can hide.

 

Bare-bottomed aquariums are preferable, as gravel greatly complicates cleaning.

 

Adults do best in custom-made enclosures that measure at least 3’ x 4’ in area; outdoor maintenance is ideal when weather permits. Plastic-based rabbit cages and cattle troughs can also be modified as turtle homes.

 

A pool of shallow water should occupy approximately half of the cage’s area. Suitable hiding spots are important to the well-being of pet turtles; these include deep substrates into which your turtles can burrow and commercial turtle huts.  Cypress bark and similar commercial products, or a mix of topsoil, peat and sphagnum moss, may be used as a substrate.

 

The ambient temperature should be maintained at 75-85 F, with a basking temperature of 90 F.

 

Feeding

The Asian Leaf Turtle’s appetite knows no bounds…in the wild, fish, tadpoles, snails, carrion, insects, and fruit are all taken with equal relish. Pets should be offered a diet comprised largely of whole animals such as earthworms, snails, insects, crayfish, prawn, minnows, an occasional pre-killed pink mouse and a variety of fruits (figs are a special favorite). Goldfish should be used sparingly, if at all, as a steady goldfish diet has been linked to kidney and liver disorders in other turtles.

 

A high quality commercial turtle chow can comprise up to 50% of the diet. I prefer Zoo Med’s turtle diets for this and similar species.

 

The calcium requirements of Asian Leaf Turtles, especially growing youngsters and gravid females, are quite high. All foods (other fish and pellets) should be powdered with Repti-Calcium or another reptile calcium supplement. A cuttlebone may also be left in the cage. Vitamin/mineral supplements such as ReptiVit should be used 2-3 times weekly.

 

A Note Concerning Water Quality

Turtles are messy feeders, and quickly foul even well-filtered aquariums. Removing your pets to a plastic storage container for feeding will lessen the filter’s workload and help to maintain good water quality.

 

Partial water changes (i.e. 50 % weekly) are also very useful. Some folks find it easier to maintain Asian Leaf Turtles in plastic storage containers that can easily be emptied and rinsed.

 

Breeding

During the breeding season, the plastron becomes somewhat flexible to allow for the passage of the 2-4 unusually-large eggs. Females sometimes have difficulty passing their eggs, especially if the diet lacks sufficient calcium.

 

Gravid females usually become restless and may refuse food. They should be removed to a large container (i.e. 5x the length and width of the turtle) provisioned with 6-8 inches of slightly moist soil and sand. Gravid females that do not nest should be seen by a veterinarian as egg retention always leads to a fatal infection (egg peritonitis). Two to five clutches may be produced each year. Oxytocin injections are usually effective in inducing egg deposition.

 

 

Further Reading

The Asian Turtle Crisis

Black-Breasted Leaf Turtle Care

Over 30 years ago, a good friend and Bronx Zoo coworker amassed what was almost certainly the USA’s largest and most varied tarantula collection. He personally collected many of the spiders, and established several notable breeding firsts. Then as now, the massive Goliath Bird Eating Spider or Goliath Tarantula (Theraphosa blondi, then known as T. leblondi) topped the wish lists of zoos and advanced private keepers. I cared for my friend’s collection when he was studying Brown Tree Snakes in Guam. Although well-experienced in keeping large, aggressive spiders, birds, mammals and reptiles, caring for wild-caught Goliaths in the dark (I had promised not to disturb their day/night cycle) really put me to the test!

 

The huge females were ravenous, and far bolder at night than by day. They rushed at water being poured into bowls, and seemed to snatch dead pinkies before they hit the terrarium floor. I was hampered by the lack of a headlamp, working instead with a flashlight clamped between neck and shoulder. All went well until something jumped from the wall onto my arm, then to my chest. I froze, but was relieved to see that the “visitor” was the resident Tokay Gecko and not an irritated tarantula! Today we’ll look at the care of these fascinating but somewhat demanding spiders.

 

A Giant Among Giants

As invertebrate enthusiasts know, the Goliath Tarantula is the world’s largest spider. While the Giant Huntsman Spider (Heteropoda maxima) and one or two others may slightly top the Goliath’s near 12 inch leg span, none approach its bulk. One account lists a weight of 175 grams for a captive female…by comparison, the average house mouse (wild, not lab) tops out at 20-30 grams!

 

At present, the genus contains two other species, – T. apophysis, described from Venezuela in 1991, and T. sterni, described from Guyana in 2010. The Panama Red-Rumped Tarantula was included in Theraphosa for a time, but is now classified as Sericopelma rubronitens.

 

A Note Concerning Handling

While certain tarantula species may become relatively calm in captivity, they cannot be “tamed” and should never be trusted on bare skin – Ignore You Tube videos to the contrary, please! Goliath Tarantulas usually remain high strung, even when provided with ideal captive conditions. They are very quick to flick hairs and bite when a threat is perceived. I and several arachnologist friends have worked with tarantulas at home, in zoos, and in the field for 50+ years without being bitten…because we do not handle tarantulas!

 

If it becomes necessary to move a tarantula, do so by urging it into a plastic container with a long handled tongs. Wear goggles around New World species, as all can flick urticating hairs into the air when disturbed (please see photo of “bald patch” on a tarantula). A colleague of mine required cornea surgery to remove the hairs shed by a Mexican Red Knee Tarantula. Hairs remaining on hands, terrarium tops, and other surfaces are as dangerous as those recently shed by a spider.

 

All tarantulas are capable of delivering a painful bite. Human fatalities are unknown, but their venoms are relatively unstudied, and an allergic reaction is always possible. A doctor should be consulted immediately if a bite is suffered.

 

The Terrarium

Goliath Tarantulas are best kept in screen-covered aquariums.   “High” style tanks are ideal, as they spend most of their lives in deep burrows, and will be stressed if not provided with such (some individuals adapt to surface caves, but burrows are preferable). Be sure to use extra cage clips on the cover, as tarantulas can climb glass and are incredibly strong. A 20 gallon aquarium is adequate, but I (and, I presume, the spiders!) much prefer a tank of 30-40 gallons capacity.

 

A wide variety of live plants may be used, although the spider may disturb these until a burrow site is chosen, Earth Stars (Cryptanthus) and other tough, low-light species are ideal; please post below for further information.

 

Substrate

A mix of coconut husk, top soil, and peat moss works well with these rainforest natives. Add just enough water so that the substrate sticks together when squeezed…keeping it so will prevent burrow walls from caving-in. Sphagnum moss can be worked into the soil in order to improve its moisture-holding capacity. Some keepers have done well by using 4-5 inches of substrate, but I provide adults with 8-12 inches or more.

 

Wild tarantulas often excavate burrows (or take over those occupied by their last meal!) beneath fallen logs, tree stumps and other cover. Several of the burrowing species I’ve cared for have used turtle huts and similar structures as starting points for their burrows. These and other caves should also be available for use until the spider constructs its own retreat.

 

Some keepers bury cork bark rolls with one edge facing the terrarium glass, and construct a tunnel that leads to the surface. In this way, the spider can sometimes be observed within its burrow. Please post below for further information.

 

Light and Heat

Red or black reptile night-viewing bulbs will not disturb your spiders and will assist you in observing their nocturnal activities.

 

Goliath Tarantulas are native to northern South America’s hot, humid rainforests and riverside thickets. They should be maintained at a temperature gradient of 80-86 F. Night-viewing bulbs, sub-tank heat mats and/or ceramic heater emitters can be used to warm the terrarium. All heat sources will dry out the terrarium, so it is important to monitor humidity.

 

Humidity

Proper humidity levels are critical to good health, normal activity, and successful shedding (becoming stuck in a molt is a leading cause of death among captive Goliath Tarantulas). This tropical forest native requires humidity levels in the range of 75-85%. A hygrometer (humidity monitor) is an essential piece of equipment for the serious tarantula keeper. In dry environments, a small mister should be considered.

Just before and during the molt (please post below for further details re molting) humidity can be increased by partially covering the terrarium’s lid with plastic. As air flow is critical to good health, this option should only be used for limited periods.

 

Food and Water

While some folks have had success with cricket-based diets, variety is preferable, especially if breeding is contemplated. I’ve done well by basing the Goliath diets on roaches and earthworms, with crickets being used less often. I also offer katydids, locusts, field crickets, moths and other wild-caught insects during the summer months, and notice that these often induce a very vigorous feeding response (please post below for more information on using wild-caught insects).

 

Although wild Goliath Tarantulas frequently ambush frogs, lizards and, perhaps, small rodents, a vertebrate-based diet is not recommended. Pre-killed pink mice can, however, be supplied every 2-4 weeks; some keepers believe this to be especially beneficial to breeding females. These voracious predators will readily accept dead prey moved about with a forceps or, in some cases, simply left in the terrarium; live mice should not be offered.

 

Incidentally, the “bird-eating” reference arose in 1705, when Swiss naturalist Maria Sibylla Merian included, in a book on the insects of Suriname, a painting of a Pink-Toed Tarantula consuming a hummingbird. The name she coined, “Bird-eating Spider”, remains in common usage today. While I’ve no doubt that a Goliath Tarantula would happily make a meal of any bird nestlings it might happen upon, this is likely a rare occurrence in the wild.

 

Canned grasshoppers and other invertebrates moved about with a long-handled forceps (remember, tarantulas have poor vision and may strike well above the food item – do not risk a bite!) can be used to provide occasional dietary variety.

 

Although spiders are able to obtain water from their prey, a shallow water bowl seems critical to success in keeping Goliath Tarantulas. The enclosure should also be misted daily.

 

 

 

Further Reading

Tarantula Care and Natural History

Beyond Webs: Swimming, Spitting and other Spider Hunting Strategies

The discovery of a new frog is always an exciting event, but the species revealed in this month’s issue of Zoo Keys is especially so. The colorful, entirely-aquatic Telmatobius ventriflavum was found in a small stream along a major highway 3,900 feet up in the Peruvian Andes. It is related to a unique group of frogs, the best known being the bizarre, “push-up performing” Lake Titicaca Frog (Telmatobius culeus).   I was fascinated by the huge, baggy-skinned Lake Titicaca Frogs resident at the Bronx Zoo (the only ones in captivity) as a child – and due to their 30 year lifespans, I was lucky enough to work with those same individuals once I began my zoo-keeping career!

(Please see the article linked below for more on this amazing frog). The Lake Titicaca Frog’s newly-discovered relative promises to be just as interesting – and, it seems, is similarly threatened with extinction.

 

A Strange Frog in a Harsh Habitat

The new found frog sports the odd (some say “un-nerving”) upwardly-directed eyes typical of the other 62 members of the genus Telmatobius (similar, in my mind, to those of the more familiar Buddget’s Frog) and a beautiful, bright yellow to orange abdomen.

 

The only known population occupies a narrow stream of the Huaytara River, located in a valley on the Pacific slope of the Peruvian Andes. Herpetologists were surprised by its discovery because the site is near a major highway, and in a region that has been well-studied. The frog’s bright coloration might also have been expected to draw attention. Furthermore, a completely aquatic frog was not expected in this habitat – a dry, shrub-studded alpine grassland known as the Puna. The region receives a bit of rain from January to March, after which it remains bone-dry, and it has few resident amphibians.

 

Threats: Chytrid, Dams and Isolation

Because the stream in which T. ventriflavum lives is separated from other suitable habitat by desert-like grasslands, the species is assumed to be endemic to the immediate area. The stream has dammed, but it is not known if this negatively affects the population (but it’s a pretty safe bet that it does!).

Unfortunately, some of the frogs and tadpoles that have been examined were found to harbor Chytrid fungus, which has been responsible for scores of amphibian extinctions worldwide. So far, nothing is known of the fungus’ impact on the population, but herpetologists are not optimistic. In Ecuador, 3 related species have been wiped out by chytridiomycosis, the disease associated with this fungus.

 

As T. ventriflavum is already at risk due to its tiny range and the damming of its home stream, careful study of the population, especially as regards Chytrid infection, is being considered.

 

 

Further Reading

Lake Titicaca Frog Conservation

Original Article Describing the New Aquatic Frog

 

 

 

Read More »

As Valentine’s Day draws near, I thought it might be time to give some competition to the inevitable stories that will surface concerning monogamous mammals and “gift-giving” birds. To be sure, penguins presenting mates with rocks are cute, but how many folks know about the far-more complex (and often longer-lasting!) pair bonds formed by reptiles and amphibians, and the risky – sometimes “deceitful” – gifts borne by some amorous spiders? Recent research has turned-up frogs that mate for life, skinks that build communal dwellings, monogamous alligators, nest-defending monitor pairs and many other astonishing examples of fascinating long-term relationships among our favorite creatures.

 

You Call This a Gift!?

Male invertebrates of many species utilize “nuptial gifts” to convince females of their desirability as mates…or, perhaps, to avoid becoming a meal as opposed to a father! But matters become a bit complex where the aptly-named Gift Giving Spider (Paratrechalea ornata) is concerned. In one study of 53 courting males, 70% of the silk-wrapped insects they presented to females were found to be “leftovers” – hollow exoskeletons whose contents had already been consumed by the conniving suitors!

 

Thin male spiders usually offered worthless husks, while well-fed males presented entire insects. Follow-up lab studies revealed that females accepted both intact and empty gifts (it takes time for them to unwrap the insects and discover the con-artists!), but were more likely to mate with heavier, well-fed males, regardless of the condition of their gift. While it seems that thin male spiders bearing useless gifts may be “getting away with something” if they mate successfully, it may be that females have the last laugh. Female spiders mate with several males, and may be able to store sperm. As occurs in some other species, the female may then somehow control which male’s sperm ultimately fertilizes her eggs.

 

Mate Fidelity and Cooperation among Amphibians and Reptiles

It has long been suspected that certain reptiles and amphibians form long-term relationships and engage in cooperative behavior. Several recent studies have confirmed this…and some have taken herpetologists completely by surprise. Several of my favorites follow…please post your own below.

 

Mimic Poison Frog: two parents needed

Perhaps the most surprising has been the discovery of the world’s only completely monogamous amphibian – Peru’s Mimic Poison Frog (Ranitomiya imitator). Driven by the need for close cooperation in raising the tadpoles, pairs form lifelong bonds.

 

The tadpoles are deposited in tiny, nutrient-poor pools within bromeliads, and would not survive without the unfertilized eggs provided by their mothers as food. Many other Poison Frogs do the same, but Mimic males stay near tadpole pools and call to their mates when the tadpoles need to be fed (how they know when to call remains a mystery)! A closely-related frog that places its tadpoles in nutrient-rich pools is not monogamous.

 

Great Desert Skinks: hard working, “semi-faithful” males

Although at least twenty lizard species live in family groups, only the Great Desert Skink (Liopholis kintorei) is known to cooperatively construct complex, long-term dwellings inhabited by several generations. Researchers from Australia’s Macquarie University have discovered that these subterranean homes have up to 20 entrances and separate latrine areas, and may span 50 feet or more. Tunnel maintenance duties are carried out by family members based upon size, with the largest individuals doing most of the “heavy lifting”, but all contribute some effort.

 

Mated pairs of Great Desert Skinks, which are native to the red sand plains of central Australia, remain together for years. Females seem to copulate only with their mates, but 40% of the male skinks father young “outside of their primary relationship”.

 

Rosenberg’s Monitors: tag-teaming nest predators

A 16-year-long study of Rosenberg’s Monitor (Varanus rosenbergi) on Australia’s Kangaroo Island has revealed that females are sometimes joined by males when guarding their nests. Nest-attending females attack intruding male Rosenberg’s Monitors (the main threat to eggs) whether or not their mates are present…when mates are on hand, they assist females in repelling others. Males were also observed helping their mates to cover nests on several occasions.

 

Shingle-Backed Skinks: absence makes the heart grow fonder

The Shingle-backed Skink (Tiliqua rugosa / Trachydosaurus rugosus), much loved by lizard keepers, has the distinction of being the first documented monogamous lizard. What’s more, paired individuals live solitary lives for up to 10 months of the year, but they re-connect each breeding season. Field research has shown that pairs spend an average of 43 days together during September and October, usually in close physical proximity, at which time they mate (and, one would imagine, sort out bills, “to do” lists and such!). They then go their separate ways, having little or no contact with one another until the following September.

 

Faithful Female Alligators

Biologists working with American Alligators (Alligator mississippiensis) in Louisiana’s Rockefeller Wildlife Refuge were surprised to find a high degree of mate fidelity in their study population. Writing in the October, 2009 issue of Molecular Ecology, the researchers explained that 70% of the female alligators studied over a 10 year period mated with the same male each year. This is the first time such behavior has been documented in any Crocodilian, and is rendered even more interesting by the fact that the refuge supports a very dense population of alligators, and females freely move through the territories of many males.

 

 

Further Reading

Great Desert Skink Communal Dwellings

Monogamous Frogs

 

In the past 20 or so years, the Crested Gecko (Correlophus/Rhacodactylus ciliatus), has gone from “presumed extinct” to being such a common pet that it may actually rival the Leopard Gecko in popularity! In addition to their interesting ways, innate “charm”, and extreme hardiness, these New Caledonian natives are also proving extremely easy to breed in captivity. Yet as I receive questions and review related articles and internet forums, it seems that some confusion exists on this topic. As Crested Geckos can provide a wonderful introduction to lizard breeding, today I’d like to review how best to get started. Also, since even un-mated females can produce eggs, and may suffer fatal impactions if not properly cared for when gravid, it is important for all owners to understand the basic principles of Crested Gecko reproduction.

 

Do I Have a Pair?

Crested Geckos show sexual dimorphism earlier than do many other lizards. By age 6 months or so, males will exhibit two easily-seen bulges near the cloaca, evidence of the internal male sex organs, or hemipenes. Small femoral and pre-anal pores may be visible even earlier. However, these may not be evident to folks who have not seen a good many mature males of this or related gecko species.

 

Unlike many lizards, Crested Gecko pairs may be housed together year-round. However, females that are not in breeding condition may be injured by males during unsuccessful copulation attempts. A bit of biting is normal at this time, but in small terrariums, or those lacking cover in the form of logs, plants, etc., injuries may occur.

 

Reproductive Age

Captive reptiles of many species often reach adult size faster than they might in the wild, but this does not always mean that breeding is possible or advisable.

 

Female Crested Geckos may become sexually mature by age 8 months or so, but it is best to forestall breeding until they are at least 1 – 1½ years old. Most successful long-term breeders use 40 grams as a safe weight for first-time breeding females. Males may be bred at the same or a slightly younger age, and are generally a bit lighter in weight than females.

 

Stimulating Reproduction

There doesn’t seem to be much in the way of detailed field studies of Crested Gecko reproduction. Judging from the temperature profile of their habitat, they most likely breed throughout New Caledonia’s warm season (November to April), when temperatures average 74-85 F.

 

Pets kept in temperate regions are usually stimulated to breed by local seasonal changes, beginning as the weather warms in spring and ceasing in autumn. In tropical and semi-tropical regions, well-fed females may continue to deposit eggs throughout the year. This can deplete calcium stores and otherwise impact long-term health. Cooling geckos to 68 F by day and 65 F by night, and reducing the daytime period to 10 hours, has been useful in stopping reproduction (however, this must be done gradually…please post below if you need further information).

 

Egg Deposition

Female Crested Geckos deposit clutches of 2 eggs. They usually produce multiple clutches, separated by approximately 30 days (but this number varies widely), each breeding season. Three to 5 clutches are generally considered as being typical for well-fed pets, but up to 10 have been reported.

 

In naturalistic terrariums, eggs may be secreted beneath the substrate at the base of plants, cork bark, or other cover. Gravid females are sometimes seen digging in several spots before deciding on a nest site.

 

Even if nesting sites are available in the terrarium, boxes or caves provisioned with a mix of moist sphagnum moss and soil should always be provided. This will simplify egg retrieval (if they are used, of course!) and will assure that there will always be a suitable nest site. Female geckos that cannot find a site to their liking may retain their eggs, which will eventually lead to a fatal infection (egg peritonitis).

 

Also, bear in mind that female Crested Geckos are able to store sperm. Those purchased as adults, or separated from a male, may still produce fertile eggs. As mentioned above, females that have not mated may also develop eggs, which must be deposited.

 

Stay alert for signs that a female may be egg-bound – lethargy, swollen abdomen, straining – and see a veterinarian if this occurs.

 

Egg Incubation

Crested Gecko eggs have been successfully incubated under a wide range of conditions. Here again they vary from many reptiles, as the eggs are extremely resilient and develop well at unusually-low (by lizard standards) temperatures.

 

As with most eggs, I favor course vermiculite or pearlite as an incubation medium. A water: substrate mix of 1:1 by weight works well.  The eggs may be incubated in an room with an appropriate temperature range, or a commercial reptile egg incubator.  Please see the article linked below for information on a simple method of calculating and tracking water content.

 

I haven’t found anything definitive concerning the effect of incubation temperatures on hatchling sex, but several anecdotal notes report that females predominate at temperatures of 77-80 F, males at 82 F, and mixed sexes at 70-76 F (the range most favored by experienced breeders). Incubation temperatures exceeding 84 F are said to kill the embryos.

 

Incubation periods range from 65-120 days, depending upon temperature and, in all likelihood, humidity levels and other factors.

 

Please post below for information on rearing young Crested Geckos.

 

Further Reading

Crested Gecko Substrates: Avoiding Impactions

New Caledonia Giant Gecko Care