Frogs

Every night on Planet Earth, ponds, lakes, streams, marshes, and even forests come alive with the deafening chorus of lively amphibians called frogs. Listen closely and you can hear the deep, resonating ruuum, ruuum, ruum of the bullfrog or the peep-peep of the spring peepers’ serenade, or maybe the hoarse croaking and clucking of the leopard frog.

Each frog and toad species has its own unique call, and uses its musical talents to celebrate the night: as a defense call, as an injured or scared call, or to attract a mate to its side. The loudest calls occur during early spring and summer as male frogs try to attract females to the water. The male bullfrog can be heard over a mile away. Their eardums are twice as large as the female’s, and they vibrate to increase volume.  Some frogs also have pouches of skin under their throats called vocal sacs, which swell up like a balloon, and act like a megaphone to amplify the calls of these colorful amphibians.

Amphibians are animals that are cold-blooded, have no scales, and return to the water to breed. The word “amphibian” comes from the Greek words “amphi” and “bios” which mean double life. That’s because frogs and toads begin their life as eggs in the water and move onto land for much of the remainder of their lives.

There are over 4900 species of frogs and toads on Earth and they live on every continent except Antarctica. From lush tropical forests to frozen tundra to parched, scorched deserts, these frogs and toads have been masters of survival for over 200 million years—almost as long as the dinosaurs!

Being small and not aggressive has made frogs and toads a plentiful food supply for animals and birds higher up on the food chain. Herons, egrets, owls, and other birds prey on frogs in the tall grass at the edges of lakes and ponds.  Bobcats, snakes, alligators, and raccoons regard frogs as a tasty meal. Sometimes larger frogs eat smaller frogs! Through many adaptations to their environment, however, frogs have survived for hundreds of millions of years because each species has found a special way to adapt.

There’s the old “try to look bigger than you are” approach
The Mexican Burrowing toad and Budgett frog do this very well: they puff themselves up when they are threatened by a predator.

There’s the “I’m warning you—I’m poisonous” approach!
Very brightly colored frogs like the Blue Dyeing Poison frog from Surinam and Brazil and the Strawberry Poison Dart Frog  from Central America flash their vivid colors as a warning that they taste bad or are poisonous if eaten. Native Indians wipe the tips of their spears across the Poison Dart Frog’s back and use the poison-tipped spears for hunting animals.

The “Blend in with the Surroundings” approach
Some frogs like the Sr iLankan Rock Frog perched on this rock blend perfectly with their surroundings. The green shades of other frogs are an almost perfect match to the leaves or foliage around them. Others like the blue/green treefrog sport colors and patterns that mimic the leaves they perch on. This treefrog, with its whitish and light green spots or rings resembles a wet, decaying banana leaf with spots of fungus.

The “Confuse-the-heck-out-of-em” approach
Bright patterned colors on the inside of frogs’ back legs called flash coloration confuse predators when the frog leaps away—the striking colors make the frog appear to be a different shape.

The “Bury Yourself with a Good Friend” approach
The Great Plains Narrow Mouthed frog actually burrows in the ground for shelter…and has been known to share its burrow with a tarantula.

The ol’ “Take a taste of this” approach
Toads have many glands on their skin that secrete a foul-tasting, often irritating, and sometimes poisonous fluid. One taste of this fluid and the pesky predator quickly drops the toad!

The “Zig, then Zag” approach
When pursued by a predator, the Northern Leopard Frog flees in a zig-zag pattern, making it almost impossible to catch.

And then there’s always the opportunity to attack first!
The Budgett’s Frog assumes a sit-and-wait pose ready to ambush predators. It will lunge at, bite, and then shriek at an intruding animal. And if that isn’t enough, it inflates itself so that it appears even larger than it really is! With large teeth in its upper jaw and two fangs in its lower jaw, this frog has all the tools it needs to ward off predators!

Many frogs do have teeth—but they are usually tiny teeth and are located only along the upper jaw. Most frogs have sticky tongues, which are attached to the front of their mouth. When a frog spots an insect, it flips out its tongue, catches the insect, and rolls its tongue back in. Scientists have  discovered that a frog’s tongue actually acts like a catapult, and the muscles in the center of its tongue become stiff as the frog flicks its tongue out. Soft tissue on the end of the frogs tongue slaps down on the food like a dishrag, and the frog's tongue instantly snaps back in again.  Frogs eat insects, earthworms, minnows, mosquito larvae, sometimes snails, and even smaller frogs.

Some frogs and toads lunge at their prey instead of using their tongues. All frogs gobble down their prey in one piece.  Did you know that when frogs eat, they sink their eyeballs down into their head to help them swallow?

Because a frog's eyes stick out from its head, it can see almost all the way around, not just in front of it--that’s called panoramic vision. Frogs are adept at seeing objects that move quickly—like a fly buzzing nearby, or a mosquito droning overhead. And because many frogs are more active at night— or nocturnal -- many have excellent night vision.

When humans focus their eyes on an object, they change the size of the lens in their eyeball. When a frog focuses on a bug or other prey, its eyeball actually moves forward and back like a camera lens to hone in on the object.

Skin
Frogs and toads breathe and drink through small openings in their skin called pores.  Everything that touches their skin is absorbed through these pores into their body.  If frogs and toads live in an unhealthy environment, they will be unhealthy; their eggs will be unhealthy; and future frogs and toads will be unhealthy.

Did you know that frogs are recyclers? They shed the outermost portion of their skin, sometimes up to once weekly. And many eat their skin as they shed it, which recycles valuable nutrients back into their body.

Frogs exist in almost every color of the rainbow—stunning blues, soft grays, vibrant reds, fiery oranges. Some are even multi-colored – dotted, striped, leopard spotted—almost any color and pattern you can imagine.

The difference between frogs and toads
Frogs and toads do look different. One of the best ways to tell a frog from a toad is by looking at their feet. A frog’s back feet have webbing between the toes which enables the frog to swim at great speeds. A toad’s back feet have very little if any webbing. Spadefoot toads that burrow in the dirt have a very long toe on their back feet to help them move the soil. Treefrogs who are arboreal – which means they live in trees-- have little round disks on their toes that help them stick to leaves, plants, even houses  as they hop, jump, and climb to forage for insects.

A frogs’ skin is smooth and moist. Frogs always live near the water, and their bodies are more slender and their heads more pointed than toads.
Toads are actally just a type of frog: They usually have dry, bumpy skin with warts. Toads are usually a brownish color so they can be camouflaged with rocks, tree bark, leaves, and grass, and toads are also much chubbier than frogs.

Many frog species can lay up to 20,000 eggs at a time! From 3 to 25 days later, the eggs hatch and tiny tadpoles emerge. The swimming tadpoles feed on algae in the water. From 6 to 24 months later, these tadpoles - or polliwogs, as they are sometimes called - lose their tails and become adult frogs. Their tails don’t actually fall off—they shrink back into the frogs!

Some amphibians go through these metamorphosis stages much more quickly. It takes just 2 weeks for a spadefoot toad egg to become a toad! Most frogs and toads lay their eggs on the surface of ponds or lakes. Others like treefrogs lay eggs on leaves or in pools of water in flowers.  When the tadpoles emerge, they fall off the leaves into the water. Some toads carry their eggs in their back in a special pouch, or in their stomach until they hatch. Anything to survive!

We’ve all heard the old expression “When the going gets tough, the tough get going?” Well, frogs do things the opposite way. When it’s extremely hot or extremely cold, it’s uncomfortable, and they crank it down a bit.

Frogs are cold blooded creatures, which means that the bodies of frogs stay the same temperature as the air around them. If it’s too hot or too cold, their bodies get too hot or too cold.

To live through extreme cold of winter, amphibians hibernate—or deep sleep—to escape that cold.  During the end of summer and throughout the fall, amphibians store their food as body fat, which runs their bodies all winter while they are hibernating.   A hibernating amphibian’s body saves energy by doing a couple of neat things. First, its body temperature drops very low so that it almost matches the temperature outside.  Then the frog’s heartbeat and breathing slow down, too. But to keep from completely freezing, frogs store a lot of glucose , or sugar, in their bodies.

To live through extreme heat or dry conditions, amphibians estivate or sleep  through these stressful times. No singing or mating or eating, or even growing. Their breathing slows up and their heartbeat decreases. Sometimes frogs shed a layer of skin, wrap it around themselves for protection, and wait for moisture in the form of rain before they start moving again.

Yes, being a frog has its ups and its downs. And lately frogs and toads have had lots and lots of downs: For one thing, more and more frogs and toads are dying than ever before.

One third to one half of all amphibian species are now in danger of extinction. That’s almost 2,000 species!!!  Why? Forests are being destroyed. Lakes and ponds are being drained for construction. Chemicals, insecticides, and waste are polluting waters. Frogs and toads are being removed from natural surroundings and kept as pets. Global warming is causing temperatures to rise for longer periods of time.
People are releasing non-native frogs and toads into the wrong habitats.

And the worst problem now is a killer fungus called chytrid which is wiping out amphibians around the globe. Entire populations of frogs and toads are dying. This is a serious problem.

This fungus, carried by the African clawed toad, makes it difficult for the frogs to use the pores in its skin to take in water. Frogs and toads and other amphibians are dehydrating or drying up because like all living things, they cannot live without water.

What will happen if we lose all these amphibians? Amphibians, including frogs and toads, are an important part of our ecosystems. They consume an incredible amount of insects. Without them, there would be a huge increase in the number of insects, including mosquitoes, because there will be no more frogs and toads to eat their larvae. (if you’re an insect-lover, especially mosquitoes, this shouldn’t bother you!) Snakes, birds, and mammals, which prey on frogs and toads, will have to find other food. The healthy, natural food chain that exists now will be broken.

Amphibian Ark
Scientists, biologists, and wildlife experts who are members of Amphibian Ark have taken on a huge task! They are bringing endangered amphibians into captivity where they cannot catch the deadly chytrid fungus. These amphibians will breed and produce more young. Participating zoos and aquariums will take care of these amphibians until they discover how to kill the chytrid fungus. When scientists are sure they can kill the chytrid fungus, they will return these healthy frogs to  their natural settings. This colossal task can only be achieved by people working together: scientists, teachers, zoo and aquarium directors, caretakers…and you. Frogs and toads of the world need you!

Amphibian species are becoming extinct at a pace faster than anything we have ever experienced, and we need to spread the word.
If we lose thousands of amphibian species, it will have an effect on our environment and on species all the way up the food chain.

We can all encourage more zoos and aquariums to contact Amphibian Ark and take in endangered amphibians so they can breed and produce more young. By learning more and speaking up about this, you can help save countless species of frogs and toads. After all, it’s your planet too!

www.amphibianark.org