The most dangerous are the sharks, especially the large ones like the tiger and white. In addition to these predators, other threats come from orcas – which are actually a huge species of dolphin – and from humans. “It is common for fishermen to accidentally catch dolphins in their nets”, says biologist Ana Paula Madeira Di Beneditto, from the State University of Norte Fluminense (Uenf), in Campos (RJ). When this happens, they cannot come up to the surface to breathe and they drown. Like whales, dolphins are mammals of the cetacean order. They are divided into two families: the Delphinidae, which comprises about 30 oceanic species, and the Platanistidae, with four freshwater species. On average, dolphins reach 3 meters in length, and the best known species, called the bottlenose (Tursiops truncatus), exceeds 2 meters and weighs around 250 kilos. It is these animals that take part in acrobatic shows in aquariums around the world. One of the smallest dolphins is the tucuxi dolphin (Sotalia fluviatilis), found in the Amazon, with 1.20 meters, and the largest is exactly the killer whale (Orcinus orca), which reaches almost 7 meters and threatens its smaller “cousins”. Dolphins live in groups of two to a thousand individuals and are excellent swimmers, being able to exceed 50 km/h and descend to an incredible 300 meters deep! With so many abilities, they abuse their courage against their aggressors. But they don’t always get along.
SURPRISE ATTACK
Sharks prefer to attack dolphins from behind. At first, they give a strong bite on the caudal fin to injure the agile animal and make it difficult to move. Then, when the dolphin is already weakened, the sharks bite for real other parts of the body of their prey
FACE TO FACE
When the dolphin manages to perceive the threat, it tries to face the predator. Only then is there any chance of defense. The dolphin’s natural reaction is to hit the region above the shark’s snout with its jaws (the beak in front of its head). The blows leave the big guy disoriented and make it easier to escape
ALL FOR ONE
When a shark decides to attack a dolphin in the middle of a group, the other members join together to scare the predator away. They strike the entire body of the animal, especially the snout and belly, which can cause damage to the shark’s internal organs.
DEFENSELESS
When they are free, dolphins defend themselves as best they can. But those caught in fishermen’s nets become an easy feast for the ocean’s most famous predator. Many are already dead when the shark arrives. It mainly eats the guts and muscle layer of dolphins.
EFFICIENT WEAPON
The beak or rostrum of dolphins is formed by their upper and lower jaws. In cetaceans, this bone piece is longer than in other mammals and, therefore, is used as a defense weapon. Against sharks, this can feel like a slingshot to a rifle. But sometimes it works
NEW MEAT IN THE PIECE
Cubs are the preferred prey. The feared great white shark, over 6 meters long, manages to swallow them whole. When the mother realizes that her calf is being threatened, she tries to place herself between the small dolphin and the shark to strike the attacker.