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.

Please see Part I of this article for information on the history of corn snakes (Elaphe/Pantherophis guttatus) in the pet trade and breeding preparations.

Color Strains

Young herpers may find it hard to believe that there was a time when only normally colored corn snakes were to be found in the pet trade. Today, a bewildering array of color phases and patterns are available, far more than exist for any reptile. I just reviewed a wholesaler’s price list and counted 48 color and pattern strains being offered!

Hybrids

Corn snakes have also been hybridized with closely and even distantly related species, including, respectively, black ratsnakes and gopher snakes. Indeed, the corn snake’s genetic propensity for producing numerous color morphs and hybrids is at the core of its popularity and its value in revealing to us the details of snake color inheritance and captive breeding.

Natural vs. Captive-Produced Corn Snake Colors

Oddly, the naturally colorful “Okeetee Phase” corn snakes are now less in evidence than other forms, and consequently are becoming highly prized. They really are gorgeous, and, in light of their history, hold a special interest for me. However, some of the captive-generated morphs are quite unique and its great fun to work on producing new strains. Some of the more descriptively named corn snake varieties include:

• Sun Kissed
• Sunglow
• Rootbeer Striped
• Reverse Okeetee
• Snow Striped
• Lavender Motley
• Hypo Striped
• Golddust
• Ghost Striped
• Ghost Blood Red
• Creamsickle
• Christmas
• Charcoal
• Caramel motely
• Butter Striped
• Black
• Albino Recessive Okeetee
• Albino Abberent

I’ve often thought someone should establish a collection comprised of representatives of every known corn snake color phase and hybrid…if you are on your way to that, please let me know!

Further Reading

The taxonomy of corn snakes and related species has been revised in recent years. To view its current status and learn more about corn snake hybrids, please see http://www.jcvi.org/reptiles/species.php?genus=Pantherophis&species=guttatus.

 

The books Snakes: the Keeper and the Kept and Snakes and Snake Hunting, written by Staten Island Zoo curator Carl Kauffeld, turned “Okeetee, South Carolina” into a household name for legions of snake enthusiasts worldwide (myself included). An incredibly productive snake collecting area, Okeetee was especially noted for its brilliantly colored corn snakes, Elaphe (Pantherophis) guttata, and abundant Eastern diamondback rattlesnakes (Crotalus adamanteus). A road sign from the area still graces the corn snake exhibit at the Bronx Zoo, where I worked for many years, and photographs taken from collecting trips to Okeetee in the 60’s and 70’s line the back rooms of the zoo’s 100 year old reptile house.

The Influence of Okeetee

These “Okeetee corns”, as they became known, were largely responsible for the explosion of interest in captive snake breeding in the late 60’s and 70’s, and ushered in a new age of husbandry innovations; today the corn snake remains the world’s most commonly bred snake species. Corn snakes have provided untold numbers of aspiring herpetologists with an introduction to snake keeping and snake breeding, and have played an important role in a number of research efforts.

Preparing Snakes for the Breeding Season

For those of you who plan to breed corn snakes, now (late summer) is the time to begin preparations. Your snakes should be fed heavily until autumn, at which time they can be chilled to 50-59 F (after a 2 week fast) for 6-8 weeks. Although corn snakes may reproduce at the tender age of 11 months, breeding should be withheld until they are at least 2 years of age…females that are bred too early often fail to attain full size, and tend to produce small clutches and weak offspring.

Mating occurs from March to June in most regions, with the eggs being laid 25-50 days thereafter. A second clutch may be produced in late summer/early fall. An average clutch consists of 16 eggs, but may range from 6-26. At 82 F, incubation time averages 62 days in length, and the young are 8-11 inches long upon hatching.

As we will see in Part II of this article, years of intense captive breeding efforts have produced a mind-boggling array of corn snake morphs, strains and hybrids. The reproductive cycle of all parallels that just described, but individual details, such as clutch size, etc., will vary among the various types of corn snakes.

 

Further Reading

The Southwestern Center for Herpetological Research has posted some informative notes and blog entries concerning the influence that Carl Kauffeld and Okeetee, SC have had on the snake-keeping community:
http://southwesternherp.com/cgi-bin/yabb2/YaBB.pl?num=1215719054.

The care of corn snakes roughly parallels that of black rat snakes. Please see my article The Captive Care of Black Ratsnakes for more information.

I remember well my shock when the news concerning temperature dependant sex determination (TDSD) among reptiles first broke.  Imagine…a turtle or crocodile egg can develop as either a male or female, depending upon the incubation temperature!  Well, it now seems that at least one species of lizard, the three-lined skink (Bassiana duperreyi), complicates matters even further.

 

Egg Size and Sex

Writing in the June, 2009 issue of Current Biology, University of Sydney biologists have revealed that large skink eggs develop into females, while small eggs become males.  Furthermore, removing yolk from a large egg resulted in a male hatchling, despite the fact that female genes were present; adding yolk to a small egg over-rode the effect of the male genes already in the egg, producing instead a female.

 

Temperature and Sex

Extreme nest temperatures, it seems, can also affect the hatchlings’ sex, regardless of its genetic makeup, resulting in xx chromosome males (males are usually xy) and xy females (females are typically xx).

 

Survival and Conservation Implications

The question that begs answering, of course, is why has this lizard evolved such a unique and complicated reproductive strategy?  Researchers are now looking into its ecology to determine the answer.

Understanding such matters has greatly assisted those working to conserve reptiles and amphibians.  Knowing the parameters of TDSD has allowed us to pick and choose the sexes of highly endangered species being bred in zoos, so that a favorable sex ratio can be maintained.

Of course, there were some problems early on.  I was working with green sea turtle head-start programs in Costa Rica when TDSD first came to light.  The organization I was with had been gathering sea turtle eggs for 30 years, incubating them, and then releasing the young when they had grown past the vulnerable stage.  Great in theory…but by using a single incubation temperature, we may have produced only female green turtles for the entire 3 decades!

Further Reading

You can read more about the natural history of the three-lined skink and its relatives at http://www.jcvi.org/reptiles/species.php?genus=Bassiana&species=duperreyi.

 

 

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.