Leading a Double Life

Amphibians are the first vertebrates that ventured out of the water to explore terra firma. The word "amphibian" means "double life," referring to the way many species spend part of their lives in water and part on land. Because their thin, highly permeable skin is susceptible to dehydration, amphibians must stay close to a water source throughout their lives. Amphibians have been around for about 350 million years and the first known frog appeared during the Jurassic period, 190 million years ago.

Perhaps the most fascinating thing about amphibians is the metamorphosis many undergo as they mature. Metamorphosis is characterized by a drastic, rapid change in form. Watching frog eggs hatch into tadpoles that develop into frogs is one of the most amazing things you'll ever see.

If a pet frog senses drastic changes in temperature he may enter estivation, a partial hibernation period during which he will not eat or drink and his skin will harden, giving the appearance that he is coated in plastic. His nostrils become plugged and he breathes only through his skin.

Salamanders make fun and interesting pets but should never be handled. The salt, oils and heat from our hands are lethal to "sallies." Many salamanders are drab in color, but some have beautiful, brilliant markings. Breeders work hard to encourage the proliferation of colorful salamanders for pets. Many salamanders shed their tails if threatened by a predator. The tail wiggles about for while, distracting the predator and allowing the salamander to escape. Its tail will later regenerate.