Frog and Toad
CLASS: Amphibia (Amphibians)ORDER: AnuraFAMILIES: 27GENERA: At least 303 knownSPECIES: About 4,000 known
Frogs are fascinating! The world holds a wonderful variety of frog species, each adapted to living in its unique habitat, be it cool mountain slopes, scorching deserts, or tropical rain forests. Depending on the species, they may be found in water, on land, or in trees and come in many sizes and colors.
Frog or toad? Frogs often have long legs that are good for hopping, skin that is smooth and moist, and special pads on their toes that help them climb. Toads, on the other hand, are more heavyset with shorter legs, and usually have drier skin, often with warty-looking bumps. Frogs are more likely to live in or near water than toads. The word "frog" can include both frogs and toads, as some frogs may not live near water and some toads have smooth skin.
Can you get warts from holding a toad? No! But you can die from holding a frog—if it's a poison frog! Some of these bright little South American frogs are so toxic that one drop of their skin secretions can kill an adult human. But don’t worry, as these toxins need to enter the bloodstream to cause you harm, and those in zoos are not toxic because they don’t eat the poisonous insects found in the wild that are required to produce the toxin.
When you look at a frog or a toad, you'll notice that it doesn't seem to have a neck. Practically speaking, this is true. Most frog and toad species have large, protruding eyes so they can see in most directions. They can also hop around to look in another direction. But they can't turn their head like we can, since their neck is almost non-existent.
Adult frogs and toads have two main color schemes. Each one signals a different survival technique. Those with bright colors (like poison frogs) advertise their presence and warn potential predators that their skin is toxic. Those with mottled green or brown colors are camouflaged so predators have a hard time finding them. Some species employ both strategies, such as the Oriental fire-bellied toad, which is green on top but red on the bottom. When disturbed, these toads bend upward to display their red belly and warn predators of their toxic skin.
Toads have additional survival techniques as well. If a predator is after a toad, the toad can puff itself up so it looks too big to swallow. Most toads can also secrete a burning milky toxin from a gland, called the parotoid gland, behind their eyes!
Most frogs and toads are great at hopping any which way. Powerful muscles in a frog’s back legs give it distance while pushing off from whatever surfaces it’s leaping from. Generally, the longer the frog’s back legs are, the farther it can hop. Hopping is a great way to escape from danger quickly. Some frogs prefer to walk or run rather than hop, especially those living in grasslands, and aquatic frogs use their swimming skills to make a quick getaway.
HABITAT AND DIET
Frogs and toads are found in nearly every type of habitat, almost everywhere on Earth except Antarctica. Frogs don’t have fur, feathers, or scales on their skin. Instead, they have a moist and permeable skin layer covered with mucous glands; this allows them to breathe through their skin in addition to their lungs. They can also absorb water through wet surfaces and are vulnerable to water loss through the skin in dry conditions. The thin layer of mucous keeps the skin moist and protects it from scratches.
Frogs need fresh water for their skin, so most live in aquatic or swampy habitats. There are always exceptions, though: the Australian water-holding frog is a desert dweller that burrows deep into the ground to keep from drying out. The waxy tree frog, found in the arid Gran Chaco of South America, produces a waxy substance that it rubs all over its skin to prevent evaporation.
Most frogs and toads eat insects, spiders, worms, and slugs. Some of the larger species chow down on mice, birds, and even other small reptiles and amphibians. At the San Diego Zoo and San Diego Zoo Safari Park, our frogs and toads are fed crickets, worms, fruit flies, or mice.
Frogs and toads are responsible for keeping a large part of the world's insect population under control. In some cases, however, their appetites can be a problem. Latin American cane toads were introduced to Australia in 1935 to kill sugarcane beetles. But instead of beetles, the toads preferred to eat native frogs, small marsupials, and snakes. Not only that, but they poisoned everything that tried to eat them, including rare animals like Tasmanian devils and pet dogs! Since cane toads lay more than 50,000 eggs at a time, they turned into bigger pests than the beetles they were supposed to get rid of.