The Sunday News
Poison dart frog
Description
VIBRANT but toxic, poison arrow frogs range from less than an inch to two-and-a-half-inches in body length.
There are more than 100 species of poison dart frogs, varying in colour and pattern. The black and green species has black spots, the strawberry or blue jeans frog is all red with blue legs, the yellow-banded species appears painted with yellow and black.
Colour shades vary among frogs within a species. It is the skin that contains the frog’s poison.
These beautiful colours are warnings to potential predators that the frogs are poisonous. Other species, such as monarch butterflies, sport bright colours to advertise their toxicity. Several species of non-poisonous frogs evolved with similar colouring to avoid being eaten. Some scientists think that the reticulated pattern of the frogs also acts as camouflage among the forest shadows.
Diet
Poison dart frogs feed mostly on spiders and small insects such as ants and termites, which they find on the forest floor using their excellent vision. They capture their prey with the use of their long sticky tongues.
Reproduction
Male frogs go through an elaborate ritual to attract a mate. The males vocalise, a loud shrill sound, to attract females. Once the courtship ritual is complete, the females deposit dozens of eggs on leaves. The eggs are encased in a gelatinous substance for protection against decay.
During the two-week development period, the male returns to the eggs periodically to check on them. Once the tadpoles hatch, they swim onto the male’s back and are attached by a mucus secretion, which keeps them from falling off.
The male carries them to a place suitable for further development, such as wet holes in broken trees and branches, little ponds, wet coconut shells, and even in tin cans and car tyres. Tiny pools of water that collect in bromeliads are also used by some species.
Once at their final destination, the tadpoles are on their own. They need an additional three months to metamorphose into small frogs.
Status
Some poison dart frogs are endangered due to habitat loss, which is causing numbers to decline among many species.
The possibility of new medications from these frogs’ secretions is being explored.
Fun facts
Poison dart frogs, also called poison arrow frogs, are so named because some Amerindian tribes have used their secretions to poison their darts.
Not all arrow frogs are deadly, and only three species are very dangerous to humans. The most deadly species to humans is the golden poison arrow frog (Phyllobates terribilis). Its poison, batrachotoxin, can kill many small animals or humans. Arrow frogs are not poisonous in captivity. Scientists believe that these frogs gain their poison from a specific arthropod and other insects that they eat in the wild. These insects most likely acquire the poison from their plant diet.
In 1999 a Zoo pathologist published his discovery of a then mysterious infection that was afflicting and eventually killing poison arrow frogs and white’s tree frogs.
Through his effort, cutaneous chytridiomycosis was documented for the first time as a vertebrate parasite. The veterinarians along with keepers and pathologists also developed a treatment for the chytrids. The same antifungal that is used to kill athletes’ foot in humans can be used with the frogs and toads. — national zoo
