Montshire Minute: Local Amphibians

Originally aired during the week of May 8, 2000

Monday

If you come across a long string of eggs in a vernal pool or pond in the spring, you may be looking at embryos of an American toad. The female toad lays eggs in long tubes of jelly. After the eggs make contact with water, the tube thickens to about a quarter-inch in diameter. A clutch of eggs from one American toad may contain 15,000 embryos and can extend several feet in length. American toads emerge from hibernation in March and their long musical trill, which can last from six to thirty seconds, is a pleasant sound of spring. Males call from shallow, temporary ponds, lakes, rivers, and any water-filled rut to attract females ready to breed. Their calls also advertise their positions to other males. Join us on Thursday evening, May 18, when herpetologist Jim Andrews of Middlebury College shares his extensive knowledge of Vermont amphibians and describes how to find them in the field.

Tuesday

Leopard frogs emerge from underwater hibernation in spring. From mid-April to mid-May the males rest, with limbs spread out, on the surface in the shallows of ponds or lake coves. After about ten days, the frog egg develops into a tadpole, which ventures out of the protective jelly and into the water. Feeding on algae and breathing through gills, the fully-grown tadpole is almost perfectly fish-like. One of the first signs of adulthood is the appearance of hind limbs. The tadpole also begins to depend more on its developing lungs than its gills to breathe. Soon, the animal has well-developed front legs and a head that is clearly becoming more frog-like. The full-fledged frog will only have a tail stump as a reminder of its fish-like larval stage. Join us on Thursday evening, May 18, when herpetologist Jim Andrews of Middlebury College shares his extensive knowledge of Vermont amphibians and describes how to find them in the field.

Wednesday

The largest of all American frogs is the bullfrog, which has a body-length of up to eight inches, along with ten-inch hind legs. The bullfrog will eat almost anything large enough to fit into its mouth. It reaches out with its long, flexible tongue to feed on insects like dragonflies, crayfish, other frogs, and even small birds and mammals. Bullfrogs lay up to twenty thousand eggs, which form a mass two to five feet across. Very few of the tadpoles will live long enough to see adulthood, so quantity of eggs seems to be one of nature's ways of assuring the survival of the species. Bullfrogs can live up to fifteen years, spending most of their time floating on the surface of the pond and diving into the matted undergrowth for prey. On a summer night, you'll hear their deep, sonorous call: "Jug-o-rum, jug-o-rum." Or something like that.

Thursday

If you've seen a red eft, you've also seen a red-spotted salamander. Sound confusing? Well, at first glance this animal does seem to have a split personality. When the eggs of the red eft hatch in the spring, the larvae look like little brownish tadpoles with fragile gills behind their heads. As the larva grows during the warmer months, the newt's skin will get brighter and develop red spots. By fall, the eft has its familiar bright reddish-orange coloring, which helps warn away predators. It also makes it easy for you to see the eft on the forest floor during a wet autumn day. When the cold weather sets in, the eft moves to an underground burrow where it stays until spring. As the eft continues its life on land, it turns into an adult red-spotted newt. It will retain the black-rimmed red spots, but the rest of the skin will turn a greenish color. A red eft? Yes - and a red-spotted salamander!

Friday

Ancestors of modern frogs lived tens of millions of years ago, when dinosaurs were kicking around. And they are still here today. What's the secret of their success? Well, as amphibians, frogs live in water, but they also get around just fine on land. They can escape from land predators by jumping into water (some frogs can jump 20 times their body length in a single bound!). And if there's not much to eat in the water, they can find dinner on shore. Frogs live in many different climates and can be found pretty much any place where there's fresh water. During the cold winters, many species of frog hibernate, burrowing deep in the mud at the pond's bottom. As the temperature drops below freezing, the frog's breathing and heartbeat grind to a halt. When spring finally arrives, the frog's vital signs rebound. It emerges from the mud and continues on its happy-go-lucky way.