Predators
Let’s explore the animals in the section
Alligators
Alligatorids (Alligatoridae) are a family of reptiles belonging to the order Crocodylia, currently represented by several species living in the Americas and one present in China. Alligators differ from crocodiles mainly in the morphology of the head, which is wider and shorter, with a more obtuse snout; other features relate to the legs, which are less webbed than in crocodiles, and a particular intolerance to salinity: in fact, crocodiles can better tolerate seawater due to the presence of specialized glands for salt filtration. Alligators evolved toward the end of the Mesozoic, and some primitive forms are found in Upper Cretaceous strata (about 70 million years ago) in Europe. On this continent they disappeared only in the Pliocene (about 5 million years ago). Even in North America they were already widespread toward the end of the Cretaceous and gave rise to a multitude of forms of various sizes. During the Cenozoic, alligators reached South America where they developed into giant species that later became extinct.
Crocodiles
The Nile crocodile (Crocodylus niloticus) is a large aquatic reptile, widespread in Africa along the river for which it is named and poses a deadly danger to animals living in its own environment. It possesses strong legs equipped with claws with which it climbs riverbanks with agility. Its large nostrils, located on the top of its snout and protected by a thick layer of skin, allow the crocodile to breathe even when the rest of its body is underwater. Its teeth are strong allowing it to tear large shreds of flesh from its prey; they grow continuously and are replaced by new ones all the time, but interestingly the crocodile cannot chew! The eyes are located at the top of the head to enable the animal to detect and survey prey when submerged. The tail has a dual function: excellent as a rudder, it is formidable as a weapon, strong enough to fracture the limb of a deer. The length of these animals can reach 6 meters and more, and their weight can, in adulthood or advanced age, range from 900 to 1,000 kg.
Sharks
Selachimorpha is a superorder of predatory, strong-jawed, medium-to-large cartilaginous fishes, whose members are commonly known by the name shark or sharkfish. This grouping includes more than 500 species, for which respiration occurs through the use of gill slits, generally ranging in number from five to seven. A distinctive feature of sharks’ bodies is that they are covered with dermal denticles, which not only improve their hydrodynamics but also protect their skin from parasites. These fish are also equipped with reserve teeth, which step in to replace lost or damaged ones. All sharks are carnivores, but while most feed on fish and other marine animals, larger specimens on the other hand (e.g., whale shark) feed mainly on plankton. As a result of even unprovoked attacks on humans by some species in particular, sharks have gained a reputation, only partly justified, as killer animals. Partly because of this, as well as the fact that their meat is considered prized in many Asian states, several varieties of shark are currently subjected to intensive fishing that puts them in serious danger of extinction.
Other predators
It is not only size that makes an animal a perfect predator: even organisms smaller than sharks and crocodiles can be skilled and effective prey hunters. Despite the struggle for survival, however, you can observe how prey and predators also manage to share the same habitat: small fish and crustaceans coexist with the most fearsome predators, sometimes even proving to be a help to them.
