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

The breeding habits of a poorly-studied treefrog have recently grabbed the attention of herpetologists and amphibian enthusiasts. Although it is small in size and lacks a common name, Chiromantis hansenae is quite special. Recent research has revealed it to be the only Southeast Asian treefrog known to provide parental care to its eggs. Furthermore, it breaks the typical rules that apply to most other egg-guarding frogs in important ways. Very little is known about Chiromantis hansenae, which until now was thought to be an “un-remarkable” little frog – a clear sign that important discoveries await those willing to search.

 

Eggs Die Without Mom’s Care

Chiromantis hansenae’s unexpected egg-brooding behavior was first observed by researchers from the National University of Singapore. Writing in the journal Ethology (V. 119, N. 8, p 671-679), they describe how females deposit egg masses in trees and then cover the eggs with their bodies. Egg-attending treefrogs sometimes descend to the ground and soak for a time in nearby ponds, after which they return and re-position themselves above the eggs. This behavior apparently supplies the eggs with water and also limits the amount of water lost via evaporation…most of the egg masses from which females were removed (by researchers) dried up and failed to hatch.

 

Chiromantis hansenae differs from most other egg-brooding frogs in several important ways. In other species, few large eggs are produced, and the male provides most or all of the parental care (please see photo of male Midwife Toad carrying eggs).  Such eggs are generally deposited on land, and direct development (from egg to small frog) is typical. Chiromantis hansenae, by contrast, produces many tiny eggs and deposits them above-ground, and tadpoles rather than small frogs emerge from the eggs.

 

Conservation Implications

Why has this unique breeding strategy evolved, and how many other species rely upon it? Answering such questions is crucial if we are to understand and conserve the world’s frogs, many of which are facing an extinction crisis.

 

That such a small, unassuming frog could hold these secrets should inspire us to look at all creatures with deep respect and interest. One never knows where the next unforeseen discovery will arise, or how important it will be from a conservation perspective. Despite Southeast Asia’s incredible diversity of amphibians, the study mentioned above is the first to closely examine parental care in any of the region’s frogs.

 

Unfortunately, little is known of Chiromantis hansenae’s natural history; the range, usually given as Thailand and Cambodia, is poorly-defined. The IUCN lists this frog as “data deficient”, and some herpetologists doubt that it is a distinct species, classifying it instead as the widely-ranging C. vittatus (note: the first photo, above, is of C. vittatus; you can see a video clip of C. hansenae here ).

 

Related Frogs

Chiromantis hansenae is classified in the family Rhacophoridae, along with several treefrogs that are popularly-kept in captivity by amphibian enthusiasts. Included among them are two of my personal favorites, the Chinese Flying Frog (Rhacophorus dennysi, please see photo) and the African Gray Foam Nest Frog (Chiromantis xerampelina).

 

 

 

Further Reading

Tree Dwelling, Wood-Eating tadpoles Discovered!

 

The Fang-bearing Tadpoles of the Vampire Frog

 

 

Leopard Geckos and Bearded Dragons have stellar reputations among lizard enthusiasts. In fact, they come as close to being perfect pets as any reptile can. However, there are major differences in their habits, activity levels and care needs, and it’s important to be aware of these when choosing a pet. When an animal is active, how much its care will cost, the space it needs and other factors will affect your pet-keeping experience and your new lizard’s quality of life. In the following article I’ll compare Leopard Geckos and Bearded Dragons in all relevant areas. Detailed care information is provided in the articles linked under “Further Reading”; as always, please also post any questions or observations you may have.

Reptile Handling
Most lizards are best considered as “hands-off” pets, but both Leopard Geckos and Bearded Dragons break this rule. Although individual personalities vary, both adapt well to gentle handling, and are not stressed by human contact.

Activity Levels
Neither is overly active, but both have fascinating behaviors that are well-worth watching for. Bearded Dragons are out and about by day, at which time they bask (their most common “activity”!), feed, and display to tank-mates.

Leopard Geckos, being nocturnal, are ideal for owners who are “night owls”. They will become active in a dimly lit room, or you can equip the terrarium with a black or red reptile night bulb (lizards do not sense the light produced by these bulbs). Leopard Geckos sometimes emerge during the day as well, especially if food is offered.

Life Span
A Leopard Gecko in the St. Louis Zoo’s collection lived for a record 28.6 years. The published longevity for a Bearded Dragon is 15 years, but there are unofficial reports of individuals approaching age 20.

Lizard Reproduction
Both species breed reliably, and a wide variety of color morphs are available. Please see the articles linked below for detailed information.

Cost
Bearded Dragons require larger terrariums and higher temperatures than do Leopard Geckos, and must be provided with a source of UVB radiation (Leopard Geckos and other nocturnal lizards get along fine without UVB bulbs). Therefore, Leopard Geckos are the less-expensive pet, in terms of supplies and electricity use.

Terrarium Size (single adult)
Leopard Gecko: 10-20 gallon (larger is preferable)
Bearded Dragon: 30 gallon

Temperature
Leopard Gecko: 72-85 F, with a basking site of 88 F
Bearded Dragon: 75-88 F, with a basking site of 95-110 F

Lizard Diet
Leopard Geckos are carnivorous. Young Bearded Dragons feed largely upon insects, adding plants to the diet as they mature.

Both require highly varied diets comprised of vitamin/mineral supplemented roaches, silkworms, crickets and other invertebrates. Bearded Dragons also need various greens and, perhaps, a high quality commercial food.  Mealworms and crickets alone, even if sprinkled with supplements, are not an adequate diet for either lizard. Please see the articles linked below for more information on diet.

Health Concerns (Pet and Pet Owner)
Intestinal impactions that result from the ingestion of sand and gravel are perhaps the most commonly-encountered health concern (both species). This can be avoided by the use of cage liners, or by feeding your lizards in large bowls, via tongs, or in a separate, bare-bottomed enclosure. Young lizards, being clumsy hunters, are more likely to swallow substrate than are adults.

Diseases related to poor nutrition are common among lizards maintained on crickets and mealworms alone, and in Bearded Dragons that do not receive adequate UVB exposure (Vitamin D3 is manufactured in the skin, in the presence of UVB). Both species sometimes refuse food in the winter, even if kept warm (please see this article for further information).

If a moist shelter is not available, Leopard Geckos sometimes retain the eyelid lining after shedding. Please see this article.

Atadenovirus infections are becoming increasingly common among Bearded Dragons. Unfortunately, the resulting “Wasting Disease” or “Star Gazing” is incurable. Please see this article for further information.

Salmonella bacteria, commonly present in reptile and amphibian digestive tracts, can cause severe illnesses in people. Handling an animal will not cause an infection, as the bacteria must be ingested. Salmonella infections are easy to avoid via the use of proper hygiene. Please speak with your family doctor concerning details, and feel free to post below if you would like links to useful resources.

 

Further Reading

Complete Guide to Bearded Dragon Care

Complete Guide to Leopard Gecko Care

Breeding Leopard Geckos

 

 

Although the Black Rough Neck Monitor, Varanus rudicollis, is rarely-seen in the wild, captive-bred individuals are often available.  This striking lizard utilizes a variety of very different habitats, so in a suitably large enclosure one can expect to see a many interesting behaviors.  This is definitely a species worth studying carefully, as we still have much to learn.  I’ve always wanted to feature them in large zoo exhibits, but was not able to drum up much interest, unfortunately.  Private keepers, however, have added greatly to what is known of this under-appreciated monitor.

Black Rough Neck Monitors remind me of Merten’s Water Monitors, Vanaus mersentsi, in general body form and especially in their ability to move about in trees, water and on land with equal ease (Note: the photo below is of a Merten’s Water Monitor; please click here for photos of Rough Neck Monitors)

 

Range

The Black Rough Neck Monitor is found across a huge range that extends from southern Myanmar through Thailand and western Malaysia to Sumatra and Borneo, and also inhabits nearby offshore islands.  As it is difficult to observe, many believe that the range is greater than generally accepted.

 

Habitat

Although widely distributed, the Black Rough Neck has specific habitat requirements.  It seems restricted to rainforests near permanent water bodies and mangrove swamps.  Although believed to be highly arboreal, Black Rough Necked Monitors frequently forage on the ground and in the shallows of rivers and swamps.

 

Description

The Black Rough Neck Monitor is stout in build and averages 3-4 feet in length, with some individuals reaching 5 feet.  The body color ranges from dark gray to nearly black; there is some evidence that different populations exhibit specific shades of gray or black.  The thick, pointed scales that encircle the neck are unique among monitors; I’ve not yet found a reputable published account of their function.  Extremely sharp claws (even by monitor standards!) assist it in climbing.

 

Enclosure

Like most monitors, Black Rough Necks are quite active, and will not thrive in close quarters.  Adults require custom-built cages measuring at least 6 x 4 x 6 feet; greater height is preferable.

 

Cypress mulch or eucalyptus bark may be used as a substrate.  Shy by nature, they are best provided with numerous caves, cork bark rolls and hollow logs in which to shelter, and stout climbing branches for climbing.  They prefer sheltering above ground (wild individuals often utilize tree hollows), so a cork bark roll or large nest box positioned among the branches would be ideal.

 

The cage should be located in a quiet, undisturbed area of the home, as Black Rough Neck Monitors are very aware of their surroundings and easily stressed.

 

Temperature

Black Rough Neck Monitors fare best when afforded a wide temperature gradient, such as 75-95 F; a dip to 70-73 F at night may be beneficial. The basking temperature should be kept at 120-140 F; some keepers go as high as 150F.  Incandescent bulbs http://www.thatpetplace.com/spot-day-white-bulbs may be used by day; ceramic heaters http://bitly.com/NSUMSq or red/black reptile “night bulbs” http://bitly.com/MS35s9 are useful after dark.

 

Provide your monitor with the largest home possible, so that a thermal gradient (areas of different temperatures) can be established.  Thermal gradients, critical to good health, allow reptiles to regulate their body temperature by moving between hot and cooler areas.  In small or poorly ventilated enclosures, the entire area soon takes on the basking site temperature.

 

Humidity

Humidity should average 60-85%, but dry areas must be available.  A commercial reptile mister will be helpful if your home is especially dry.  A water area large enough for soaking must be available.

 

Light

UVB exposure is essential.  If a florescent bulb is used (the Zoo Med 10.0 UVB Bulb is ideal), be sure that your pet can bask within 6-12 inches of it.  Mercury vapor and halogen bulbs broadcast UVB over greater distances, and provide beneficial UVA radiation as well.

 

Diet

The few available studies and observations indicate that wild Black Rough Neck Monitors take a wide variety of prey animals, and that the diet may vary across the range.  Rodents, bats and other mammals, although consumed when available, do not comprise the bulk of the natural diet.  Wild individuals seem to feed primarily upon grasshoppers, roaches and other large insects, frogs, crabs, and snails.  Scorpions, termites, birds and their eggs, and fish have also been recorded as being consumed.

 

A rodent-only diet will not work well for Rough Necked Monitors. Youngsters should be fed largely upon roaches, super mealworms, snails, hornworms and other invertebrates, along with small whole fishes, un-shelled shrimp, fiddler and green crabs, crayfish and squid.  Mice should be provided once weekly, and hard-boiled eggs can be used on occasion.  All meals offered to growing monitors should be powdered with calcium, and a high-quality reptile vitamin/mineral supplement should be used 3x weekly.  I favor ReptoCal, ReptiVite and ReptiCal.

 

Rodents and whole fish can comprise 50% of the adult diet, with a variety of large insects, hard-boiled eggs, crayfish, squid, shrimp, snails and similar foods making up the balance.  Calcium and vitamin/mineral supplements should be used 1-2x weekly.  Large food items should be avoided; even where adult monitors are concerned, mice are preferable to small rats.

 

Temperament

Although not a species for beginners, Black Rough Neck Monitors adjust well to captivity when given proper care, and make fine, long-lived pets.  Initially shy, some learn to trust gentle caretakers, while others remain wary even after years in captivity.  A large, well-furnished cage will provide the security which is essential if they are to become approachable.

 

In common with all monitors, they are capable of inflicting serious injuries with their powerful jaws, long tails, and sharp claws.  Thick leather gloves should be worn when handling Black Rough Neck Monitors, as even tame individuals will cause deep scratches with their claws in the course of their normal movements.

 

Breeding:

A single male can be housed with 1 or 2 females, but they must be watched carefully.  The nesting area should be enclosed (i.e. a large tub or plastic storage container within a wooden box equipped with a single entrance hole) and stocked with 2-3 feet of a slightly moist mix of sand and top soil or peat moss.

 

Egg deposition generally occurs within 35-50 days of mating, but captive conditions can greatly affect the gestation period.  Clutches contain 4-15 eggs, which may be incubated in moist vermiculite at 85-90 F for 180-200 days.  Double and triple-clutching has been recorded. Hatchlings measure 8-11 inches in length and are attractively banded with yellow.

 

 

 

Further Reading

Dwarf African Clawed Frogs, also known as Dwarf African Frogs (Hymenochirus boettgeri and H. curtipes) are very popular pets, yet few hobbyists attempt to breed them in captivity. Reproduction sometimes occurs spontaneously, but unless one is prepared, the eggs and tadpoles rarely survive.  As both a lifelong frog enthusiast and career herpetologist, I find this to be a sad state of affairs.  For these tiny aquatic frogs can be easily induced to breed and exhibit some of the amphibian world’s most amazing reproductive behaviors – including a circular egg-laying “dance” that may go on for 7 hours!  The bizarre tadpoles are equipped with tubular mouths and swim in a head up position at the water’s surface, propelled by rapidly-beating tails.  Looking somewhat like tiny skin-divers, rearing a tankful of these charming little amphibians is a most interesting and pleasurable undertaking.

Distinguishing the Species and the Sexes

Hymenochirus boettgeri and H. curtipes are the only species regularly available in the pet trade.  Hymenochirus boettgeri has proportionally longer rear legs than H. curtipes, and its skin appears more granular.  The tadpoles are easy to distinguish (please see below).

Females are larger than males, and they are positively rotund when carrying eggs.  Males can be distinguished by their postaxillary glands, which appear as a tiny white bump behind each forearm. Read More »

Breeding reptiles is one of the most rewarding and enjoyable aspects of our hobby.  It is quite important as well, as zoos have neither the time nor space to care for all the species that are, or will soon be, in need of help.  Relatively common reptiles also deserve attention, as lessons learned about their reproductive biology are often applicable to rarer relatives.

ZooMed’s reptile egg incubator, marketed as the Reptibator, utilizes heating technology that is a vast improvement over older (and very expensive!) incubators that I used while working at the Bronx and Staten Island Zoos.  In addition to allowing for finer temperature and humidity control, the Reptibator’s Pulse Proportional Thermostat conserves energy while cutting electric bills. Read More »