Mary Allen
Dolphins belong to the cetaceans and are mammals. They are between one and a half and four meters long. The killer whale, the largest dolphin, can even grow to be eight meters long. There are 40 species of dolphins in total. The “bottlenose dolphin” is probably the most popular and well-known among humans. Dolphins live in groups called “pods”.
Many people believe that dolphins are fish. However, three features, in particular, show that dolphins are mammals, like all whales: They have to surface to breathe. They don’t have scales, just smooth skin. The young animals drink milk from their mother.
How do dolphins live?
Dolphins live in all seas on earth. But there are also river dolphins. Dolphins can swim very fast. They can reach speeds of up to 55 kilometers per hour. This is slightly more than is allowed in our cities with a vehicle. Dolphins also swim very far every day. It is therefore unnatural to keep them in an artificial tank.
Dolphins feed on fish and sometimes crabs. They are fast predators. They have a specific organ in mind: the “melon”. An echo is sent out from there, which comes back again when it encounters prey, for example. This is how dolphins always know when something is near them.
Dolphins live in groups like other whales. These groups are also called schools. They also use echo to communicate with each other.
In the dolphin, only half of the brain sleeps. The other half takes care of breathing. One eye also remains open and observes the surroundings.
Mother dolphins only carry one cub in their belly for about a year. Like all whales, the mother squirts the milk into her baby’s mouth because it has no lips to suckle. After a few months, the young animal searches for its own food. It stays with its mother for up to six years.
What is a danger to dolphins?
The biggest danger for dolphins is fishing nets. They can get caught in the nets and drown. Usually, the fishermen don’t want to catch dolphins at all, but tuna. When dolphins get caught in such nets, they suffocate because they cannot surface. In some countries like Japan, however, dolphin meat is also eaten.
Other dolphins die because people catch them. They do not survive being caught, die while being taken from the water, or die held captive by humans. Among other things, there are soldiers who train dolphins to fight in the water or to find mines. Most dolphins are caught for zoo shows.
A natural danger is the depth of the water or mud on the seabed. Then dolphins sometimes cannot perceive their own echo. That’s why it can happen that they get stranded.
Their enemies include large sharks and killer whales. So killer whale eats other dolphins too. In particular, dolphins can catch diseases or fungal infestations.