Year of the frog

Over the past three decades, amphibian populations have dropped by an estimated 30 percent.

By STUART WINER
frog 88 (photo credit: )
frog 88
(photo credit: )
While many may be familiar with the survival challenges facing animals such as rhinoceroses, tigers and giant pandas, there is an entire class of animals that is facing extinction. Amphibians the world over are under threat. To draw attention to the problem, zoos and aquariums have declared 2008 the Year of the Frog. The Jerusalem Biblical Zoo is doing its part and has opened a new amphibian exhibit in the Small Animal Enclosure. The exhibit includes a selection of newts, salamanders, frogs and toads local to Israel. The dramatic drop in global amphibian populations is cause for much concern and contention among zoologists. Over the past three decades, amphibian populations have dropped by an estimated 30 percent as a result of pollution, destruction of local habitats, the unnatural introduction of predators and climate changes. Frogs are in the most serious danger because, in addition to these aforementioned threats, a lethal fungal infection is spreading at an alarming rate and wiping out frog communities. So far, the fungus hasn't reached Israel but there are concerns that illegal pet traders may inadvertently bring contaminated species into the country and unleash an epidemic. As a precaution, the zoo will run a breeding program in parallel to the exhibit to help bolster the shrinking frog population. The life cycle of frogs follows four stages starting with an egg that hatches a tadpole. The tadpole grows and enters a period of metamorphosis during which it sprouts arms and legs and develops into an adult frog. Adult frogs breathe air through their lungs above the surface, but underwater they breathe through their skin. Growing up as a frog is perilous. Although each female may lay tens of thousands of eggs, only a few offspring will survive into adulthood. Many eggs are eaten by other water dwellers, and of those that hatch, the tadpoles become prey to a whole range of predators sharing the pond. Those that do make it to adulthood quickly return the sentiment. Frogs eat just about any living prey that is smaller than themselves, including fish, insects and even each other. Just how long frogs can live in the wild is unclear but some captive specimens have lived for 40 years before they eventually croak. Frogs are usually heard rather than seen and the familiar "ribbet" sound is the male mating call. One of the most common curiosities about frogs is how they differ from toads. There are only minor differences between the two. Frogs live nearer to water and have long hind legs for hopping and swimming compared to toads, which have shorter hind legs and prefer to walk. Frogs also have narrow bodies while toads are fatter. The easiest difference to spot is in the texture of their skins; frogs have smooth skin whereas toads tend to have rougher skin with warts. After all, in the fairy tale it is a frog and not a toad that turns into a handsome prince. However, dreamy maidens in search of their Prince Charming should be wary before they pucker up and smooch their little green friend: Frogs contain poisons that can cause a skin rash.