Toothed whale
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Dusky Dolphin ( Lagenorhynchus obscurus )
The toothed whales ( Odontoceti ) are one of the two suborders of whales ( Cetacea). They are distinguished mainly by the eponymous presence of teeth, the shape and number varies strongly within the group. In addition, they possess only in contrast to the baleen whales ( Mysticeti ) one, not two blowholes. Toothed whales are carnivorous and feed mainly on fish, squid, and in some cases of marine mammals.
The most famous and richest same family of toothed whales, the dolphins.
Anatomy
Almost all toothed whales are much smaller than the baleen whales. Only the sperm whale is considered one of the great whales. The remaining species are small to medium in size. Furthermore, toothed whales of baleen whales differ in that they have only one blowhole.
The teeth are pronounced quite differently in different species. Many toothed whales have very many teeth, up to 100 in some dolphins. In contrast, the narwhal has a long tusk and the almost toothless beaked whales males have oddly shaped teeth. In toothed whales, it is relatively easy to determine the age. Each year forms on their teeth, a new layer - which corresponds in fact roughly the annual rings of a tree. The oldest of the toothed whales, the one found so far, was a sperm whale with 70 rings. For bottlenose dolphins, one starts from a peak age of 40.
Behavior
Locomotion
Most toothed whales are fast swimmers. The small species occasionally ride on waves, such as the bow waves of ships. Particularly common are encountered as the spinner dolphins, which are also known for their acrobatic leaps.
Tones
Vocalizations play an important role in toothed whales. In addition to numerous whistling sounds to communicate they have mastered the use of ultrasonic sounds for echolocation. This sense is especially useful when hunting is of great importance.
Social behavior
Most toothed whales live in groups of a few to a dozen animals. These so-called schools may temporarily join together to form larger accumulations up to thousands of whales. Toothed whales are capable of complex services in a position about the cooperation in the hunt for fish. In captivity, some species show a high learning ability, which is why they are counted by zoologists to the most intelligent animals.
Taxonomy
It divides the extant toothed whales in seven families:
- Sperm whales ( Physeteridae )
- Beaked whales ( Ziphiidae )
- Underway dolphins ( Platanistidae )
- River dolphins ( Iniidae )
- Gründel whales ( Monodontidae )
- Porpoises ( Phocoenidae )
- Dolphins ( Delphinidae )
There are several approaches to summarize superfamilies these families. Secured Quite alone, that the families of dolphins, porpoises and whales Gründel are related. These are collectively sometimes referred to as dolphin -like ( Delphinoidea ). However, the systematics of four species of river dolphins is controversial. Sometimes they were grouped in a family, sometimes referred to as simply convergent developed animals divided into four families. After molecular genetic investigations, the special position of the swing dolphins and the summary of the remaining three genera ( Inia, Pontoporia and Lipotes ) in a joint family is more likely. Sperm whales and beaked whales are probably pretty original families of toothed whales and are more closely related to any other family.
Human influence
The sperm whale has long been hunted intensively for the industry, mainly because of the Ambra previously used for perfumery. While some small cetaceans such as the pilot whale hunt is made even today, most species are mainly threatened by bycatch. In particular, in the tuna fishery, thousands of dolphins drowned in the nets.
The attitude of small cetaceans, mostly bottlenose dolphins, killer whales and belugas, is a major attraction for oceanaria and zoos. However, it is controversial because of the large space requirement of the marine mammals. The same applies to the use in the dolphin therapy.