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

Overview
The frilled dragon was a creature of legend to budding American herpetologists growing up in the 60’s and 70’s – we devoured what little published information existed, but seeing one alive was out of the question, short of a trip to its habitat.  It is still hard for me to imagine that, as a Bronx Zoo reptile keeper, I acquired my first 2 individuals a mere 15 or so years ago (at $1,500 each!).  Today these magnificent lizards are commercially bred in large numbers – both on “farms” in Indonesia and by herptoculturists worldwide.

Although not an “easy” species, and certainly one requiring a good deal of space, frilled dragons are among the most rewarding lizards to keep, and will provide you with a lifetime of interest and enjoyment.  This week we’ll take a look at their natural history, so that we can better understand how to provide for these fascinating animals in captivity.

Physical Description
The body color ranges from grayish through orange-brown to nearly black, often with dark variegations along the sides, and usually matches the color of local tree trunks.  The inner surface of the frill (the large skin fold about the neck) is shaded in yellow, black, orange and/or red.  The hind legs are powerfully built.  Males can reach 38 inches in length; females are somewhat smaller.

The neck frill is supported by cartilaginous rods and is connected to muscles in the tongue and jaw.  It expands when the lizard gapes its jaws and is used to intimidate predators and rivals, and in courtship displays.  Frilled dragons are one of the few lizards to use bipedal locomotion – they flee predators by rising up and running off on their rear legs.

Range and Habitat
Frilled dragons are found in northern Australia and southern New Guinea.  They frequent open tropical and warm temperate forest and wooded scrub land.

Largely arboreal, they dwell in the forest canopy during the dry season.  During this period the lizards reduce their food and water consumption, metabolic rate and body temperature.  The rainy season is largely spent on tree trunks within 4-15 feet of the ground.

In northern Australia and other parts of the range, frilled lizard habitat is subjected to frequent fires (natural and human induced, as a component of habitat management) during the dry season.  Field research has revealed that the lizards escape the fires by re-locating to the highest branches of large Eucalyptus trees.  Interestingly, it was also found that a number of individuals descend to the ground and shelter in abandoned termite nests during fires – a most unusual (and, it would seem, learned) behavior for an arboreal lizard.

Status in the Wild
Populations appear stable; protected by the Australian government.

Diet
Caterpillars, scorpions, ants, termites, beetles, spiders and other invertebrates, small lizards and snakes; nestling birds and small mammals are taken on rare occasions.

Frilled dragons seem to occupy a unique feeding niche within a lizard-rich habitat.  Although largely arboreal, they feed on the ground by dropping from their tree-trunk perches to intercept passing insects and small animals.

Research has shown that, immediately after dry season fires, the percentage of large invertebrates in the frilled dragons’ diets increases significantly.  It seems that the lizards are able to see larger prey animals more easily once the ground cover has been burned off.  So strong is this effect that lizards living in unburned areas move into the burned areas as soon as the fires have subsided.

Reproduction
Males are highly territorial and fight for breeding rights.  Both sexes use neck frill displays during courtship and territorial disputes.  Mating coincides with the start of the rainy season.  Females bury 8-14 eggs in the ground, and may produce 2 clutches each year if food is plentiful.  The eggs hatch in approximately 69 days and the young average 2 inches in length.  Hatchlings stay in close proximity to each other, possibly as a defense mechanism, for approximately 10 days.

Frilled Dragon Relatives
Frilled dragons are classified within the family Agamidae, which contains over 300 species.  Some of its members are among the most common and typical lizards of their habitats, while others have extremely specialized diets, unique adaptations and very restricted ranges.  Most hunt beetles, spiders, scorpions and a wide variety of other invertebrates, but the dabb lizards, Uromastyx spp., of  North Africa and the Middle East are herbivorous (in captivity they are especially fond of dried split peas!) while Australia’s thorny devil, Moloch horridus, subsists entirely upon ants.

The toad-headed lizards, Phrynocephalus spp. and the pygmy lizards, Cophotis spp. are unique among the Agamids in bearing live young.  Toad-headed lizards inhabit the deserts of south and central Asia, and utilize microscopic channels among their scales to funnel dew to the mouth.  Southeast Asia’s slow-moving pygmy lizards, likened by some to chameleons, have prehensile tails and dwell in high-altitude moss forests.

Perhaps the most commonly-seen of Africa’s lizards are various species of the genus Agama (commonly known as “agamas”), males of which perch on fences and houses and bob their brightly-colored (often blue) heads in courtship displays.  As with most Agamids, their head and body coloration intensifies during the breeding season.   Equally conspicuous throughout much of India and Southeast Asia are the various Calotes species, often locally referred to as “garden lizards” due to their propensity to take up residence near people.  Australia’s bearded dragon, Pagona vitticeps, is a popular pet, with millions bred yearly by hobbyists to supply the trade.

Among the more unusual Agamids are the 40 or so species of Draco, the “flying lizards”.  These supremely adapted aerialists are the only lizards to have developed elongated ribs to assist in gliding (flying geckos, Ptychozoon spp., also glide, but utilize small skin flaps along their sides).  The flying lizard’s ribs are covered by loose-fitting, brightly colored skin (the patagium) that, when extended, allows for “flights” of at least 50 feet and for considerable in-air maneuverability.  Other unique family members include the cold-tolerant Himalayan agama, A. himalayana, which ranges to 11,000 feet above sea level, and the horned agamas, Ceratophora spp., males of which sport a long, flexible appendage on the tip of their snouts.

We still have a lot to learn about the spectacular frilled dragons – please observe yours closely, and pass along your ideas and questions.  I’ll be sure to include them in future articles.

Excellent summaries of two frilled dragon field studies are posted at:
http://www.publish.csiro.au/paper/WR9890491.htm
http://www.environment.gov.au/biodiversity/publications/series/paper3/fire17.html

Introduction
The snake world is full of species that “break the mold” – none more so than a Southeast Asian import that sometimes appears in the trade, the tentacled snake.

The care of this snake differs greatly from that of all others, and I’ll devote a full article to it shortly.  For now, I’d like to introduce the species to those of you who may be looking for a new challenge.

The Tentacles

The tentacled snake is unique among snakes in its possession of 2 fleshy tentacles (adjacent to the nostrils), the function of which is still unknown.  It has been suggested that they have a sensory function, detect water movement, lure prey or break up the outline of the head.

Unique Adaptations
This inactive snake resembles a water-logged root, an effect that is heightened by its color, rigid posture, habit of remaining anchored to sunken branches, and the covering of algae that grows on the scales.  It rarely swims, waiting instead for fish to approach closely before striking.

Completely aquatic, this species lacks the broad ventral scales of terrestrial snakes and is helpless on land.  When disturbed, it becomes rigid and immobile (in Thailand, it is known as the “Board-like Snake”).  The nostrils can be sealed to exclude water, and it may remain submerged for 30 minutes before surfacing to breathe.  Tentacled snakes are thought to aestivate by burrowing into the mud during droughts.

Tentacled snakes produce mild venom that is effective against the fishes and tadpoles upon which they feed.  The venom has not been shown to be dangerous to humans – the two people I know of who have been bitten experienced mild swelling that disappeared within a few hours.

Unusual Relatives
The subfamily to which this species belongs, Homalopsinae, contains a number of aquatic snakes that frequent unique habitats and hunt in unusual ways.  For example, the white-banded mangrove snake, Fordonia leucobalia, hunts crabs on tidal mud flats in Southeast Asia and northern Australia.  It is quite effective at overcoming this unusual prey – utilizing constriction and crab-specific venom before finally tearing off the crab’s legs.  It may even employ its oddly blunted teeth to help crush its victims’ hard shells – the only snake known to use teeth in such a fashion.

Further information on tentacled snake natural history, as well as a picture, is posted at:
http://eobasileus.blogspot.com/2008/02/utterly-outrageous-tentacled-snake.html

Herp enthusiasts are, along with entomologists and exterminators, the only people who actively seek out termites – but we have good reason.  These insects (fascinating in their own right, by the way) are a valuable food source for a number of reptiles and amphibians.  Termites are particularly important for poison frogs, and form a major component of the natural diet of many species.

 

Termites are a valuable food for small terrarium animals, and for the young of others, because our options are limited with regard to such creatures.  Most consume a wide variety of prey in the wild, but in captivity must make due with pinhead crickets, fruit flies and springtails.  I have used termites to feed the young of a number of reptiles and amphibians (other than poison frogs) including five-lined skinks, flying frogs, marbled salamanders and others too numerous to mention, as well as species which remain small as adults (alpine newts, spring peepers, dusky salamanders etc.).  The rapid decline of many animals imposes upon us an obligation to become more effective in our captive breeding efforts – I urge you to experiment with termites and other insects.

 

To make a termite trap, simply take a plastic storage box – the shoebox size works well – and cut several holes of 2-3 inches in diameter into the 4 sides.  Stuff the box with damp cardboard and you’re all set (termites relish cardboard – I guess if your normal diet is wood, something softer seems like a treat!).

 

Search for termite nests beneath rotting logs and under the bark of dead trees.  Your trap should be located about a foot away from the nest, buried so that the top of the box is flush with the ground’s surface.  Cover the lid with a thin layer of earth and secure with a rock.  The termites will establish feeding tunnels to the box.  Remove the termite–laden cardboard from time to time, but leave the box in place so as not to disturb the tunnels.  Those more mechanically skilled than I may wish to construct PVC tube-within-a-tube systems with screw-off tops, but the plastic box works just fine.

 

For those of you with wide interests – termites are also eagerly consumed by tropical fish, finches, red-crested cardinals, sunbirds, bulbuls and other cage birds, and invertebrates such as whip scorpions, ground beetles and flower mantids.  The termite life cycle is very complex – escaped workers (those individuals that you will catch) cannot establish new colonies in your home – any termites that may infest your home will arrive courtesy of a colonizing queen, so please don’t blame me!

 

 

Interesting correspondence between hobbyists using termites as frog food (and a man who has trained his dog to detect termites!) is posted at: http://www.utoronto.ca/forest/termite/Decompiculture/Decompiculture/Termiticulture_emails.htm

Note: Please see Tarantulas in Captivity: An Overview of Popular Species for information on other species and an overview of tarantula-keeping.

 

Sri Lankan Ornamental Tarantula, Poecilotheria fasciata

Beautifully colored in gray and greenish-brown with an overlying pattern of light gray, these striking, arboreal tarantulas hail from Sri Lanka and neighboring southern India.  The undersides of the first 2 pairs of legs are bright yellow, adding greatly to the effect of their threat display.

Although they do well in captivity, it must be remembered that these spiders are fast-moving and high strung, with possibly the most powerful tarantula venoms known (such has not proven dangerous to people, but, as with all venoms, the potential for severe allergic reactions exists).  They should not be handled.

 

Ornamental tarantulas should be housed in a tall terrarium with ample climbing surfaces.  A hollow branch or bamboo stick should be provided as a hiding spot – unlike pink-toed and other arboreal spiders, ornamental tarantulas do not construct substantial silken retreats.  They occur in habitats subjected to a prolonged dry season – in captivity, a daily misting of water will satisfy their needs. Ornamentals are one of the few tarantulas that can sometimes be kept in groups (the pink toed tarantulas, Avicularia spp., are the other; please see Part I of this article for cautions) – several spiderlings have even been observed feeding upon the same insect!  Their diet should consist of roaches, crickets, waxworms and wild-caught insects such as moths.

 

Suntiger Tarantula, Psalmopoeus irminia

Venezuela’s suntiger is quite large for an arboreal tarantula, and strikingly marked in black and red.  These qualities, and its relative hardiness, have added to its popularity in recent years – in fact, this species has even been hybridized with the closely related Trinidad chevron tarantula,

P. cambridgei (the offspring are sterile and not brightly-marked). 

 

Suntigers require high humidity and should be kept in a tall terrarium over a moist substrate  and sprayed with water daily.  Clumps of damp sphagnum moss  wedged among the branches and other climbing surfaces will also help in maintaining moisture levels.

Ravenous predators (feed them crickets, roaches, waxworms, moths and other insects) and quick to “take offense”, these beauties live up to the “tiger” portion of their name quite well!

 

Haitian Brown Tarantula, Phormictopus cancerides

This species was formerly imported in large numbers, and was relatively inexpensive for such a large spider.  The state of Florida now prohibits its sale, and importations have fallen off, but captive-hatched animals are regularly available.

 

Native to Hispaniola (Haiti and the Dominican Republic) and Puerto Rico, with close relatives in Cuba, this large, ground-dwelling spider is dark brown in color.  The males are infused with an attractive purple iridescence.  Field reports indicate that they are less likely than other tarantulas to use a specific shelter, and may wander about in search of prey in the manner of wolf spiders.

 

Haitian browns should be kept on a moist substrate  and provided with a cave  in which to hide.  Females are long-lived, easily reaching the 20 year mark in captivity, but their size and willingness to bite and shed urticating hairs renders them unsuitable for those new to tarantula-keeping.  In common with tarantulas from similar habitats, Haitian browns relish earthworms (worms are usually rejected by arboreal and desert-dwelling spiders).  They will also take crickets, roaches, wild-caught insects and dead pink mice.

 

Mexican or Arizona Blond Tarantula, Aphonopelma chalcodes

This is one of the few North American tarantulas to have become popular in the pet trade, and with good reason – adapted to the harsh conditions of their Sonoran Desert (southern Arizona and northern Mexico) home, females can reach ages of 20 years or more in captivity.  It is also a beautifully-marked spider that exhibits an unusual degree of sexual dimorphism – females are tawny brown with dark basal (close to body) leg segments, while males are slate blue with orange to reddish abdomens.

 

Mexican blond tarantulas construct burrows of up to 2 feet in length, the entrances of which are covered with silk by day, apparently to conserve moisture.  This species’ life history is strongly influenced by environmental conditions and its activity levels are cyclical in nature.  The spiders may remain sealed within their burrows for 6 months at a time, while in July and August the males wander about en masse in search of females.

 

Mexican blonds should be housed in a terrarium with a deep (they do best if allowed to construct burrows), dry substrate of gravel and sand.  They are quite docile, but this should not be taken to mean that they can be carelessly handled (please see Part I of this article).  Like all desert-adapted spiders, they require but a light misting of water every few days, and are prone to fungal infections if kept under damp conditions.  Captive-born Mexican blond tarantulas, even those several generations removed from the wild, seem tuned to an “internal clock” and may go off-feed for extended periods.  As they store a great deal of food in the abdomen, and have experimentally gone without feeding for up to 2 years, this is not a concern for healthy individuals.

 

Oklahoma Brown Tarantula, Aphonopelma hentzi

This native of the American Midwest is only rarely encountered in the trade, and its care is similar to that of the Mexican blond tarantula (see above).

 

I mention it here due to an interesting peculiarity in its natural history.  The burrows of this spider are often inhabited by the 1 ½ inch long Great Plains narrow-mouthed toad, Gastrophryne olivacea.  Despite the amphibian-eating propensities of most tarantulas, the toad remains unmolested by its huge host.  Possibly, it is protected by skin toxins or, it is theorized, the toad performs a service by consuming tiny flies, ants and other insects that might parasitize the tarantula or consume its eggs.  The toad, in return, receives a safe, moist home and the protection of an aggressive predator.

 

Scores of other tarantulas and spiders, as well as scorpions, millipedes, pill bugs, centipedes, mantids, roaches and other invertebrates, make fascinating terrarium subjects.  It has been my good fortune to have studied a number of species in the wild, and to have helped establish the Bronx Zoo’s invertebrate collection.  I will post addition invertebrate-oriented articles from time to time. 

 

A comprehensive, well-illustrated article on tarantula biology and natural history is posted at:

http://www.thebts.co.uk/old_articles/natural.htm

While working in a large tropical bird exhibit at the Bronx Zoo some years back, I was startled to come across tiny frogs hidden among the leaf litter.  I was able to identify them as Greenhouse frogs, Eleutherodactylus planirostris (an apt name, it turns out).  These 1.4 inch-long Cuban natives have been transported around the world, hidden among plants and soil.  Their eggs are laid on land, and the tadpole stage is passed within the egg, so the frogs readily establish themselves in greenhouses and other warm, humid habitats.  It always pays to (discretely) poke around in walk-through zoo exhibits and such places – you never know.

 

The greenhouse frog belongs to the family Eleutherodactylidea, which contains over 800 species.  Recent research at Pennsylvania State University revealed that all types currently found in Mexico, Central America and the Caribbean arrived there by rafting on vegetation over the open seas from South America, rather than across an ancient land bridge, as was previously assumed.  Apparently, individuals of a single species landed in Mexico, and others (again, 1 species) in Central America, and then each evolved into the large number of species found in these places today.

 

Another world traveler, the Flowerpot snake (or Brahminy blind snake), Ramphotphlops braminus, also utilizes a unique reproductive strategy to establish new populations in far-flung habitats.  All individuals of this species are female and reproduce via parthenogenesis, so only 1 animal is needed to start a colony.  I’ve had the good fortune of running into this odd creature, as well as “banana” spiders, rattlesnakes and others, in unexpected surroundings – more on that next time.

 

 

An informative article on this frog’s history in Florida, along with a photo, is posted at:

http://nis.gsmfc.org/nis_factsheet.php?toc_id=205