American Bullfrog

Type: Amphibian
Size: (adult female) 3.5 to 6 in (9 to 15 cm)
Weight: 1.1 lb (0.50 kg)
Group name: Army or colony
Diet: Carnivore
Average lifespan in the wild: 7 to 9 years

The baritone call of the bullfrog is so deep and resonant, it resembles the mooing of a cow, hence its name. Only males emit this trademark "jug-o-rum" bellow, and their choruses can be heard during the day or night.

The largest of all North American frogs, this giant can grow to a length of 8 inches (20 centimeters) or more and weigh up to 1.5 pounds (750 grams). Even the tadpoles of this species can reach 6.75 inches (17.2 centimeters) in length.

They are among the most wide-ranging of all North American amphibians, found in freshwater ponds, lakes, and marshes from Nova Scotia, Canada, throughout the continental United States, and as far south as Mexico and Cuba. They have even found their way to Europe, South America, and Asia.

Bullfrogs are typically green or gray-brown with brown spots and have easily identifiable circular eardrums, or tympanum, on either side of their heads.

Nocturnal predators, they will ambush and eat just about anything they can fit in their ample mouths, including insects, mice, fish, birds, and snakes. They sit quietly and wait for prey to pass by, then lunge with their powerful hind legs, mouths open wide.

Males are highly territorial and will aggressively guard their land. Females are slightly larger than males.

Green Eyed Tree Frog

Type : Amphibian
Size: 2.8 in (7cm)
Group name : Army
diet : Carnivore

The green-eyed tree frog has adapted its appearance to blend in with the moss-covered rain forests of Queensland, Australia. The frogs' coloration and markings vary with their specific habitat, but they usually have a brownish-green body with rust-colored blotches that match the lichen-covered rocks lining the creeks and streams they tend to live near.

This species gets its name not for green eyes per se, but rather for a line of brilliant green that often adorns the brow of each eye. They are also distinguishable by a row of skin flaps along their arms and legs, which resembles a serrated knife.

Females, which are significantly larger than males, grow to about 2.8 inches (7 centimeters). Males, which emit a mating call that sounds like a quiet tap-tap-tap, max out at about 1.8 inches (5 centimeters).

Green-eyed tree frogs are abundant in the rugged wet tropics of northeast Queensland, near the Great Barrier Reef. Their population is healthy in the region's lower elevations, but, for unknown reasons, may have disappeared completely from the higher-altitude areas. They have suffered serious declines in the past, possibly due to a fungus or virus, but their numbers have rebounded, and they are not currently threatened or endangered.

American Crocodile

Type: Reptile
Size: Up to 15 ft (4.6 m)
Weight: Up to 2,000 lbs (907 kg)
Group name: Bask (on land) or float (in water)
Average lifespan in the wild: Up to 70 years
Diet: Carnivore

The American crocodile is considered an endangered species in nearly all parts of its North, Central, and South American range. Survey data, except in the United States, is poor or nonexistent, but conservationists agree that illegal hunting and habitat depletion has reduced populations of this wide-ranging reptile to critical levels.

A small, remnant population lives in southern Florida, but most are found in southern Mexico, Central America, the Caribbean, and northern South America. Their habitat of choice is the fresh or brackish water of river estuaries, coastal lagoons, and mangrove swamps.

A prehistoric-looking creature, it is distinguishable from its cousin, the American alligator, by its longer, thinner snout, its lighter color, and two long teeth on the lower jaw that are visible when its mouth is closed.

This species is among the largest of the world's crocodiles, with Central and South American males reaching lengths of up to 20 feet (6.1 meters). Males in the U.S. population rarely exceed 13 feet (4 meters), however.

Their diet consists mainly of small mammals, birds, fish, crabs, insects, snails, frogs, and occasionally carrion. They have been known to attack people, but are far more likely to flee at the sight of humans.

Most countries in the American crocodile's range have passed protection laws, but unfortunately, few governments provide adequate enforcement.