All toads are frogs, but not all frogs are toads. Determining which is which can difficult. This pet giant toad has a chubby body and warty skin like most toads.

The Washington Post/ Giuliana Nakashima

It’s tough to be a frog these days — or a toad, for that matter: 2008 has been named the Year of the Frog by a number of environmental groups to raise awareness of the plight of amphibians worldwide.

What, you didn’t know they were in trouble? Between one-third and one-half of all amphibian species are threatened with extinction, the conservation group Amphibian Ark says. Loss of habitat is the major threat, affecting the most species, but a disease called chytrid fungus is also proving deadly.

Frogs and toads make up one of three main groups of amphibians. There are about 3,500 known species of frogs and 300 kinds of toads. They can be found on every continent except Antarctica.

All toads are frogs, but not all frogs are toads. Determining which is which can difficult.

Matt Evans, a biologist and herpetologist (an expert in reptiles and amphibians) at the National Zoo in Washington, provides a lesson in the basics. Here are some differences between an American toad and a bullfrog, two species you just might see hopping around your neighborhood.

AMERICAN TOAD

Brown to brick-red to olive. Brownish spots, brown to orange-red warts. Belly usually spotted.

Parotid gland: Oozes poison if the toad is stressed

Eyes: Do not bulge from the body

Ear: External eardrum disk, or tympanum

Skin: Dry and warty

Body: A bit chubby

Legs: Short; used for walking and hopping but not jumping

BULLFROG

The largest frog in North America. Green to yellow back with cream or white belly.

Parotid gland: None. “Frogs have skin glands that can secret toxins, but they are [generally] not as toxic as toads,” Evans says.

Eyes: Bulge from the top of the head, letting them see in nearly all directions.

Nose: Longer, more pointy than a toad’s

Skin: Smooth, moist

Ear: Large disk

Body: Long, leaner than a toad’s

Legs: Long and powerful for jumping

Hind feet: Large webs for swimming

Like all amphibians, frogs and toads begin their lives in the water, breathing with gills; as adults on land, they breathe with lungs.

You are most likely to see a toad in your yard or garden; frogs prefer ponds and other still waters. Both animals must return to water to lay their eggs. “Frogs tend to lay eggs in clumps: a single egg surrounded by other eggs, like a ball of eggs,” Evans says. “A lot of toads lay their eggs in a single line, so it’s like a string of eggs.”

A lot can be learned about frogs and toads by observing them. For example, if a toad feels threatened, it will lean forward on its front legs and pump its lungs full of air to appear larger. A frog will tend to flee, using its powerful legs to hop to safety.

Evans reveals a little-known fact about frogs and toads: “They actually use the inside of their eyes to push food down into their throats.” You can see this more clearly in frogs, Evans says: “Frogs have big eyes. You always see a frog blink when it’s swallowing. The eye socket goes down into their mouth, so when they swallow, their eyes push down and help push food that’s in their mouth back into their throat.”

Frogs and toads generally do not use their front legs to grab food or assist them in eating. They have a long, sticky tongue that’s hinged at the front of the mouth so it can rapidly flip out and capture insects. And the frog’s teeth aren’t used for chewing. “They’re bringing a food item in that’s alive when it comes to their mouth; they have to swallow it immediately,” Evans says.

If you encounter a frog or toad, Evans says be careful if they are secreting toxins. “If you get it on your hands and rub your eyes, it could cause some stinging and some burning. I’d say, after you handle them, just wash your hands.”

But you won’t get a wart. Evans says that’s a myth.

Fun facts1

Fun facts

• A group of frogs is called an army; a group of toads is a knot.

• One American toad can eat as many as 1,000 insects in a day.

• Frogs and toads do not need to drink. Their skin absorbs water.

• The largest frog is the Goliath frog of West Africa. It can grow to more than a foot long.

• The “horned toad” is neither toad nor frog. It’s a lizard.

• The bullfrog is believed to be the only animal that never sleeps.

• Some frogs can jump 20 times their body length in a single leap.