Alligators and Caimans

have four feet. In this way, they are very similar to lizards. They are distinguished by their great size and ferocity. Several rows of bony plates that look like spines or teeth run down the length of their back They can stay in the water for long periods of time, and they are able to swallow underwater without drowning. They make their nests in holes on the beach. The Johnston's, or freshwater, crocodile, of tropical northern Australia, can gallop to the water by raising all four feet off the ground.

How They Move

^^ Although their preferred form of movement is swimming or crawling, crocodiles can run for short distances if they feel threatened. They can reach speeds of up to 9 miles per hour (15 km/h) when running, with their abdomens supported above their knees and their elbows slightly bent. They can go even faster when sliding on mud.

TEETH

number from 64 to 68. The fourth tooth on the lower jaw is visible when the mouth is closed.

Alligators and caimans are almost completely limited to freshwater. They make their nests by piling up grass, dirt, and leaves to lay their hard-shelled eggs. The female often remains near the nest to keep would-be thieves from invading. Although they look clumsy, alligators can use their jaws with precision. The female often helps her eggs to hatch by putting them in her mouth, where she rolls them against her palate with her tongue until they crack

NILE

CROCODILE

Crocodylos niloticus

The Largest on the Nile he impressive Nile crocodile is considered one of the most dangerous animals in Africa. It is one of three crocodile species that live in Africa and one of the largest species in the world. It can reach nearly 20 feet (6 m) in length and weigh over 2,200 pounds (1,000 kg). It lives in freshwater lakes and rivers. This dark olive-colored giant has a terrible reputation for devouring humans. For this reason, it has been both hated and revered, especially in ancient Egypt, where crocodiles were mummified and worshipped.

Range

^^ Nile crocodiles live all along the Nile ^^ River and throughout sub-Saharan Africa. They are also found in ocean waters near the African continent and the island of Madagascar. They inhabit river deltas, lakes, large swamps, and estuaries and are currently raised in many countries, such as Kenya, Tanzania, Israel, Indonesia France, Japan, and Spain.

NILE

CROCODILE

Cocodrylus niloticus

Class

Reptilia

Length

20 feet (6 m)

Range

Africa

Weight

2,200 pounds (1,000 kg)

i

6 feet

(1.8 m)

Weight

175 pounds (80 kg)

Habits

On land, crocodiles usually crawl on their bellies, although they can also raise their bodies and walk or run with their legs extended. Since they constantly need an external heat source, it is common to see them sunning themselves with their jaws open. This allows the breeze to cool the membranes of their mouths, regulating their body temperature. They are perfectly adapted for life in the water and use their tails for swimming.

SCALES ALONG THE BACK

we'll protected

Body scales serve as armor. Webbed feet help them to swim.

Range

Weight

175 pounds (80 kg)

Habits

SCALES ALONG THE BACK

we'll protected

Body scales serve as armor. Webbed feet help them to swim.

REPTILES AND DINOSAURS 59

Hunter is a phenomenal predator. It can eat fish, ind even buffalo. It can also jump out of the rom their nests. In spite of their solitary s may join together to eat and work as a allow waters. They eat animals that Ige to drink by dragging them into the water 1 tearing them to pieces.

Stalk

Ith surprising :s large size, the e stalks its prey

Attac

When huntin attacks whei the water to

Bn€y Females

^^ The female lays from 16 tb 80 eggs in^ hole well ( ^^ above the water level. She t/ill use this same'nest throughout her life. She carefully protects the^ggs v^ilej they incubate. When the young hSt<fli,^ie carefully pjj(K the hatchlings and carries them to the water in groups. Mother and offspring stay together for six to eiglit weeks then gradually separate.

HATCHLING

The young crocodiles will live in burroi^^p to 10 feet"(3 m) long for the first four years of their lives.

warthog

Phacochoerus africanus

THE AMOUNT OF TIME THEY CAN REMAIN UNDERWATER

60 LIZARDS AND CROCODILES

The American Example

Caimans also belong to the order of crocodilians. These fierce reptiles live exclusively in the tropical regions of the Americas, mainly in lakes and swampy regions. Occasionally, when looking for food, they enter areas populated by humans. The caiman family includes the genera Caiman, Melanosuchus, and Paleosuchus. The largest species is the black caiman, so named because of the color of its hide.

Black Predator

BLACK CAIMAN

Melanosuchus niger

^^ The black caiman is distinguished from other ^^ caimans by dark stripes on the lower part of its mouth and yellow lines along the sides of its body. However, it is similar to other caimans in its feeding habits, which depend on its age. Young caimans feed on arthropods and amphibians, while adults eat fish, birds, and mammals, or snails if other foods are scarce. Caimans do not have a large appetite. For example, in captivity they consume only 14 ounces (400 g) of meat twice a week.

Habitat

Equatorial Amazon River

Lifestyle

Aquatic

30 years

Weight

880 pounds (400 kg)

DROP IN NUMBERS

This species is in danger of extinction because of poaching.

Weight

175 pounds (80 kg)

Reproduction

^^ Caimans mate in the water. Once the eggs have ^ been fertilized, the females begin to build their nest, forming a mound out of dry vegetation and earth. With their hind legs, they dig a hole in the center where they lay their eggs—from 30 to 75 at a time. When finished, they cover the nest with earth. In some cases, the females return to the water and have nothing more to do with the eggs.

NEST

The eggs that are exposed to the air, which are not kept as warm, will hatch as females.

MOTHER WITH YOUNG

Some females fiercely defend their offspring.

FUTURE FEMALES

Melanosuchus niger BLACK CAIMAN

REPTILES AND DINOSAURS 61

Large Mouthfuls

^ Caimans' teeth are not used for chewing or cutting but to trap, ^^ hold, and puncture the bodies of their prey. When a caiman's victim is large, such as a capybara or a wild boar, it twists its body in the water to tear off a chunk and swallow it. Caimans also hide their prey underwater to soften their body tissues. This makes it easier to rip off mouthfuls of flesh, which they swallow whole.

SKIN SENSORS

ARRANGEMENT OF TEETH

Caimans have five teeth in their upper front jaw, 13 to 14 in the rest of their upper jaw, and 18 to 19 in their lower jaw.

TOOTH NEW

Lost teeth can be IN USE TOOTH replaced.

In the state of Louisiana a white alligator with no skin pigmentation lives in captivity. This trait would make it vulnerable in the wild, because it would be unable to absorb energy from the sun, a process that is crucial for many reasons, especially for the maintenance of its body temperature, allowing it to have enough energy to attack its prey.

NOSTRILS ABOVE THE WATER

SUBMERGED BODY

ADULT SPECIMEN Adults spend most of the day in the water. At night they come on shore to hunt.

Turtles and Snakes

GREEN TREE PYTHON

This tree-dwelling green python usually coils around a branch and waits with its head hanging down, ready to attack. It eats small mammals and birds.

SLOW BUT STEADY LONG-LIVED GIANTS TURTLES IN THE WA! INTERNAL STRUCTUF

Turtles and Snakes

GREEN TREE PYTHON

This tree-dwelling green python usually coils around a branch and waits with its head hanging down, ready to attack. It eats small mammals and birds.

SLOW BUT STEADY LONG-LIVED GIANTS TURTLES IN THE WA! INTERNAL STRUCTUF

n this chapter, you will discover the amazing world of turtles and snakes. You will learn what they are like inside, where they live, and how they hunt their prey, as well as why some eat only eggs and others, such as constrictors (the most primitive snakes), have to suffocate their prey by coiling around it. This chapter will also reveal interesting facts about turtles' skeletons and shells (for example, turtles that swim have streamlined shells that enable them to glide easily through the water). Although people may think that turtles are peaceful creatures, many are actually carnivorous hunters that eat small invertebrates, fish, and even some larger animals.

0 0

Post a comment