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

The Panamanian golden frog (Atelopus zeteki) is one of the world’s most highly endangered amphibians, but has entered the pet trade from time to time and is sometimes seen in private collections. I’ve had the good fortune of working with these Neo-Tropical gems at the Bronx and Staten Island Zoos, and would like to highlight their amazing natural history and desperate plight here.

Description

Golden frogs reach a mere 1.4 – 2.5 inches in length, with individuals inhabiting dry forests being 2/3 the size of wet forest dwellers (please see “Habitat”, below).

Slim and long-legged, golden frogs are clad in bright gold, brilliant to pale yellow, or greenish-yellow. The black markings they sport range from random blotches to small spots, or may be entirely absent. The head is longer than it is wide, and the snout is pointed.

Sub-adult frogs are very different from adults in appearance, being vivid green with black markings. This color scheme provides excellent camouflage among the moss-covered boulders of their streamside habitat.

Most people are surprised to learn that this species is classified in the family Bufonidae, along with the familiar American toad. It usually moves with a peculiar, ambling walk.

Range

Golden frogs are known only from the Cerro Campers-Valle de Anton region of western Panama.

Habitat

Golden frogs are restricted to the margins of swiftly flowing streams on the montane slopes of Panama’s Central Cordillera rainforests and cloud forests, at elevations of 335-1,315 meters above sea level.

There are 2 distinct habitat types, wet forest and dry forest. Animals within wet forest habitats congregate on streamside boulders, to a height of 9 feet above the ground; dry forest frogs forage mainly on the ground. In both habitats, females move into the forest with the approach of the rainy season, while males tend to remain in the territories that they have established along the streams.

Communicating by Sign Language

The Panamanian golden frog has evolved a number of adaptations that allow it to breed in swiftly flowing streams, which are relatively hostile environments for small amphibians.

Males utilize hand waving and foot movements, known as “semaphoring”, in order to advertise their presence to females and to discourage other males. This communication system has apparently evolved in response to the deafening noise of the waterfalls in the streams where these frogs reproduce…vocal signals from such a small animal would be ineffective.

Males that intrude on another’s territory are attacked, and a wrestling bout ensues.

Eggs

A single egg strand, containing 200-650 eggs, is laid by each female. The egg strand is attached to a large rock, which protects it from fast currents. The eggs hatch in 7-10 days.

Tadpoles

The tadpoles are dark with golden flecks and have an adhesive disc on the ventral surface that allows them to cling to rocks in fast-moving streams. They feed by scraping algae and diatoms from the surface of submerged rocks, and congregate at the edges of pools below cascades.

In captivity, tadpoles transform over an unusually variable time period…75-265 days.

Metamorphosis

Newly transformed frogs differ greatly from adults in appearance, being vivid green with black markings. They also differ in behavior – whereas the adults are diurnal and quite bold, young golden frogs hide among moss covered streamside boulders.

It is believed that sub-adult frogs lack the potent skin toxins of the adults, and therefore rely upon camouflage for protection.

 

Further Reading

You can read about golden frog conservation projects at

http://www.inibico.org/Projects/Atelopusproject/tabid/39/Default.aspx?PageContentID=8.

Image referenced from Wikipedia and originally posted by Jeff Kubina.

Aeromonas hydrophila is a common species of gram negative bacteria that often infects captive frogs and salamanders. It is particularly prevalent during the warmer months, when high temperatures stress amphibian immune systems (even tropical species often spend much of their time in cool micro-habitats) and leave them vulnerable to microorganisms that might otherwise have been resisted. Aeromonas infections are usually referred to as “red leg” or “Septicemia”.

Symptoms

Red leg, so named because the red lesions associated with it often first appear on the skin where the rear legs meet the body, is contagious and can be transmitted by contact with infected water, animals, wood, etc. The skin hemorrhages that typically occur become progressively deeper and the skin eventually sloughs off. Afflicted animals may also twitch, convulse, and become comatose. If not treated in its early stages, the condition is almost always fatal.

Improved sanitation is an immediate first step to take. Hands must be washed after handling animals and enclosures, for your own and your collection’s benefit. Environmental conditions such as poor hygiene will contribute to Aeromonas outbreaks, as will overcrowding.

Refrigeration as Treatment

Red leg is sometimes cured or by refrigeration at 39 to 41°F for two weeks. This treatment, pioneered in laboratory colonies of leopard frogs, has also been successfully used with Mexican axolotls. It appears that the immune systems of some amphibians function more effectively at low temperatures, while Aeromonas bacteria does best under warmer conditions.

The beneficial effects of low temperatures are not limited to red leg alone…while working at the Bronx Zoo I twice submitted “dead” salamanders (a mudpuppy and a hellbender) for necropsy, only to find them alive and well after a night in the animal hospital’s refrigerator!

Medical Treatment

When working with animals afflicted by any type of infection, it is very important that you contact your personal physician for advice concerning possible health risks to you and other members of your household.

While lacerated skin would lead one to believe that Aeromonas is the culprit, a definite diagnosis can only be made by blood culture performed by a veterinarian. This is important because a number of other species of bacteria, including Pseudomonas and Salmonella, may cause similar lesions, and the treatment of each will likely vary. Opportunistic bacteria and fungi, which commonly colonize the open wounds, must also be addressed.

Further Reading

An interesting early case history of a red leg outbreak among captive frogs is posted at https://kb.osu.edu/dspace/bitstream/1811/5136/1/V66N01_087.pdf.

 

One of the world’s rarest amphibians is being bred by dedicated hobbyists and is now available in the US pet trade. Anderson’s salamander, Ambystoma andersoni, which was only formally described in 1984, is limited in range to a single high altitude (6,000+ feet above sea level) lake and stream in south-central Mexico (Laguna de Zacupa, Michoacan, Mexico).  The IUCN lists it as “Critically Endangered”.

Rare Aquatic Salamanders of Mexico’s Highlands

Anderson’s salamander is part of a complex of similar aquatic, neotenic salamanders which includes the Mexican axolotl (A. mexicanum).  Neotenic species retain larval characteristics such as external gills and an aquatic lifestyle upon maturity.

A dozen or more species of these unique, poorly-studied amphibians inhabit mountain lakes in Mexico.  Most are found only in a single lake or, in the case of the axolotl, may exist only in canals and other habitat remnants. Some, including the Dumeril’s salamander (A. dumrelii), seem to have adapted to waters that are somewhat saline in nature.

Hope for the Species’ Survival

The sole population of Anderson’s salamanders is threatened by pollution, habitat loss and collection for the (human) food trade.  Its relative, the Mexican axolotl, was saved from extinction by captive breeding efforts, and is now in the unique position of being one of the most common captive and rarest wild salamanders.

Originally surfacing in Europe, captive-bred Anderson’s salamanders are now available in the USA as well.  This represents a unique opportunity for serious hobbyists to help learn about and conserve an endangered species. As a bonus, Anderson’s salamander is large, beautifully patterned and relatively hardy as well.

Keeping Anderson’s Salamander

The captive husbandry of Anderson’s salamander is similar to that of the Mexican axolotl (please see article referenced below)…please write in if you are interested in becoming involved what may become a most worthwhile amphibian breeding effort.  At this point, noted salamander specialist Michael Shrom is likely the only person breeding Anderson’s salamanders in the USA. You can contact Michael at shrommj at ptd.net.

Further Reading

You can read more about the natural history of Anderson’s salamander and its relatives at http://www.mexico-herps.com/caudata/ambystoma/ambystoma-andersoni.

For information on the Mexican axolotl, please see my article The Natural History and Care of the Mexican Axolotl http://blogs.thatpetplace.com/thatreptileblog/2008/12/19/the-natural-history-and-captive-care-of-the-mexican-axolotl-ambystoma-mexicanum-natural-history-part-1/.

Photos courtesy of Michael Shrom.

Please see Part I of this article for information on other aspects of breeding the White’s treefrog (Litoria infrafrenata): distinguishing the sexes, preparation for breeding and egg-laying.

The Tadpoles
At 80-85 F, White’s treefrog eggs will begin to hatch in 24-40 hours. The tadpoles remain largely inactive for the first 1-3 days, during which time they should not be fed. Once they begin moving about, food should always be available.

While some have raised White’s treefrog tadpoles on simpler diets, I have been most successful when using a variety of food items. In some cases, tadpoles raised on 1-2 foods develop normally, but the froglets expire within a month or two of transforming. I feed White’s treefrog tadpoles tropical fish flakes, algae wafers, and kale, romaine, dandelion and other greens that have soaked in hot water for 10 minutes or so.

Transformation
Well-fed tadpoles will transform within a month or so of hatching. Some will invariably lag behind, and may remain within the tadpole stage for an additional 4-6 weeks.

The tadpole rearing tank should be well-stocked with live floating plants such as water lettuce, water hyacinth and pothos, and lit by a Reptisun 2.0 bulb (please see Part I of this article). The plants, and a gently sloping reptile basking platform will provide the metamorphs with easy egress from the water.

The Young Frogs (Metamorphs)
Rearing a large number of froglets can be quite a challenge. Overcrowding, especially in situations of limited air flow, rapidly leads to highly contagious fungal infections of the skin. Screen cages  provided with numerous perching sites make ideal rearing enclosures.

Diet
Young White’s treefrogs usually feed vigorously, taking ¼ inch crickets, small waxworms, roach nymphs and similarly sized insects. If you are raising a large number of frogs, consider culturing flightless houseflies (available via biological supply houses). These insects are ideally sized, readily digestible and reproduce rapidly. The Zoo Med Bug Napper Insect Trap  can be employed to help provide the frogs with important dietary variety in the form of wild-caught insects.

All insects offered the frogs should be powdered with vitamin/mineral supplements  for the first few months following transformation.

The White Lipped or Indonesian Giant Green Treefrog (Litoria infrafrenata)
Native to extreme northeastern Australia, New Guinea, Timor and the Solomon Islands, this striking relative of the White’s treefrog inhabits swamps, rainforests, farms and suburban yards. It is the world’s largest treefrog, reaching a snout-vent length of nearly 6 inches.

White-lipped treefrogs tend to be high strung, and do not take well to handling. They should be housed in a large, well-planted terrarium provisioned with numerous perches and arboreal hideaways. This frog is less cold-tolerant than its plucky relative; ambient temperatures of 78-82 F by day and 74-76 F by night suit it well.

White lipped treefrogs may be bred as has been described for White’s treefrogs, but during the cooling-off period temperatures should be kept at 70 F during the night, and 74 F during the day.

Dietary variety for both adult white-lipped treefrogs and their tadpoles seems to be of even greater importance than is the case for other frogs. The metamorphs invariably develop skin problems if crowded or kept without adequate air circulation.

Further Reading
You can read more about the natural history and captive care of the white-lipped treefrog on the web site of the World Association of Zoos and Aquariums.

Image referenced from Wikipedia and originally posted by PicTrans.

For as long as I can recall, distinguishing between young African clawed frogs (Xenopus laevis) and adult dwarf clawed frogs (Hymenochirus boettgeri or H. curtipes) has been problematical for many frog keepers (and pet store employees!). The question is more than academic, because both are exceedingly common and popular in the pet trade, and their care differs radically.

Distinguishing the Species

Both are members of the frog family Pipidae, a group of 32 species of aquatic, tongue-less and thoroughly engaging creatures. Included the Pipidae is the bizarre, back-brooding Surinam toad (Pipa pipa) and its 5 relatives.

The two can be easily distinguished by closely examining the front feet. If the fingers are webbed, then the frog is a dwarf clawed frog. If they are not webbed, then it is a baby African clawed frog. Both have webbed feet.

There are subtle differences as well – dwarf frogs are even more flattened in shape than their larger cousins, and have somewhat pointed (as opposed the African clawed frog’s rounded) heads.

Lifestyle and Care Differences

African clawed frogs are boisterous, hardy beasts that eat most anything, prepared foods included, and are easily trained to feed from the hand. Captive longevity approaches 30 years.

Dwarf clawed frogs are live food specialists. Tiny and slow moving, they incessantly search the substrate for worms and other invertebrates, and do best in warm, densely-planted aquariums. A breeding group makes for an enchanting display.

Frogs and Fish?

Unfortunately, both are often sold as “oddities” for tropical fish aquariums. This situation rarely works out…African clawed frogs consume all but the largest of fishes, and dwarf frogs are inevitably out-competed for food and perish in short order.

There are major differences in the care of both species, which I’ll cover in detail in the future. Until then, please write in with your questions and comments. Thanks, Frank Indiviglio.

Further Reading

I’ve long been fascinated by aquatic frogs, and have bred a number of species. Please see my article African Clawed Frog Behavior  for some unusual observations upon which I’m seeking the comments of other frog enthusiasts.

Both frogs can be bred in captivity, and their tadpoles have a most unusual feeding strategy. For more information and a video clip, please see Suction Feeding in H. boettgeri.

Dwarf Clawed Frog Image referenced from Wikipedia and originally posted by Mwatro