Gray whale

Gray Whale

The gray whale ( Eschrichtius robustus ) is a baleen whale that lives in arctic to warm temperate waters. The gray whale is the only member of the monotypic genus Eschrichtius and is placed in a separate family Eschrichtiidae.

• 3.1 hike
• 3.2 nutrition
• 3.3 Reproduction

• 4.1 phylogeny
• 4.2 systematics

Features

Gray whales reach a length of 13 to 15 meters and a weight of 25 to 34 tonnes. These whales are slate gray to dark gray. Due to the massive colonization of the skin by parasitic crustaceans such as barnacles and Walläuse gray whales appear at a distance often white spotted. Especially often be barnacles down on the head and the tail of the Grey Wales. The head is pointed. The rostrum is strongly arched. The fin is missing, along the back there are several hump -like bulges forth. The Fluke is relatively broad and notched. The throat of the gray whale is crossed generally of two and a maximum of up to seven furrows. On each side of the mouth there are about 150 baleen plates of 40 centimeters in length.

The gray whale has two blowholes and can emit the blowing up to four meters high. The ejected water-air mixture rises vertically upwards and appears as a heart-shaped column of mist.

The life expectancy of the gray whale is 50 to 60 years.

Characteristics of a right whale

A quite strongly curved rostrum indicates a right whale. In spite of the blue whale accordingly pointed head, the gray whale has a stronger curved rostrum in proportion as the rorqual. Also the lack of the gray whale fin is a feature of right whales. A relatively broad and notched Fluke is also typical of the animals of the right whale family.

Dissemination

Gray whales are now living only in the Pacific, this is a Western Pacific and East Pacific Rise, a population distinguished. The once living in the Atlantic gray whales have become extinct in the 17th century at the latest. This Atlantic gray whales lived off Spitsbergen, Greenland and Canada as well as in winter probably from northern Africa.

Gray whales live permanently closer to the coast than any other whale species. They spend the summer in polar waters, and migrate in the winter southward. The East Pacific population wintered off the coasts of California and Mexico. The animals of the Western Pacific hold up in the summer before Siberia and the Kamchatka Peninsula. They spend the winter before Korea and Japan.

Way of life

Gray whales are slow swimmers and can reach maximum speeds of eight kilometers per hour. Usually appear gray whales four or five minutes before they reappear. While staying the whales at the surface, they often perform jumps, where they collide with the head and upper body out of the water and can then fall back again. Often the gray whales keep it to just a few kilometers off the coast. A year is divided among the gray whales in three phases feeding, migration and reproduction.

Hike

The East Pacific population spends the summer months in the nutrient-rich regions of the Bering Sea. In the autumn migration takes place in the south where propagate the gray whales off the California coast. After a few months, they return to the northern feeding grounds. The Western Pacific population spends the summer months in the northern areas of Japan located in front of the Okhotsk Sea. Reproduction takes place in winter after a hike in southern areas of the Pacific.

Grey Whales put on their travels greater distances than any other whale species. The East Pacific population each year attracts up to 10,000 kilometers across the Pacific. This is the longest known migration of a mammal. On the hike between feeding and reproduction areas the whales form groups of up to 16 animals. Usually, however, smaller groups of two or three animals. Nevertheless, it is extremely social animals. It was observed as sick or injured conspecifics were brought to the surface to breathe.

Nutrition

The gray whale eats almost exclusively during the summer months. The gnawed fat stores have to suffice for the long trek and the propagation time. The food of the gray whale are mainly amphipods, but also copepods and small fish. As the only whale gray whale is also on the sea floor in search of food. The filtering of soil inhabitants from the mud of the sea floor is a unique diet among the baleen whales. To this end, he swirls on the deposits on the seabed. This form of food intake are adapted to the short and robust gray whale baleen. The gray whales curl up on one side and suck slowly floating the bottom sediment in. Using the Barten then the food -related sea creatures are filtered out of the mud. Usually the whales roll here on the right side, causing a faster wear the right Barten.

Reproduction

The pairing of gray whales takes place in the winter months. Sexual maturity females are often accompanied by two or more males, then opt only for a partner. After mating, the animals return for the summer months back in the nutrient-rich northern regions. The gestation period is eleven to twelve months. After the return of the dams in the southern wintering areas where calves are born. Each Walkuh can only give birth to a calf. This is usually in protected lagoons. The calves are about five feet long at birth and weigh half a ton. They accompany their mothers during the remaining time in the winter area and in the subsequent hike in the summer feeding grounds. In late summer, the calves are weaned and eventually are now on their own.

Evolution and systematics

Phylogeny

To date there is no fossil evidence for the origin of the gray whales as early fossil record only slightly different from current forms. The oldest known fossil of a skull on the basis of characteristics classified into the Eschrichtiidae whale skeleton dates from the late Pliocene ( about 3 million years ago) from the Yuchi Formation in Teshio Hokkaidō, Japan.

System

Wilhelm Lillebjorg named the gray whale at its first description in 1861 from specimens off the coast of Norway as Balaenoptera robusta. The classification of the gray whale in its own genus Eschrichtius was conducted by John Gray in 1864, who thus named it after Daniel Eschricht. Edward Drinker Cope in 1869 described the Pacific type Rhachianectes glaucus, which was united by comparing the skeletal morphology with Eschrichtius robustus, and is now regarded merely as a separate population.

The gray whale family consists of only one genus with only one type, Eschrichtius robustus. The American oceanographer Michael Hall used the term Eschrichtius gibbosus, but could not prevail. The gray whale is provided to the baleen whales due to morphological features. It combines features of the families and rorqual whales. Thus, the introduction of a systematic own family in 1951 decided for the gray whale.

A close relationship between gray whales, humpback whale the whale (Megaptera novaeangliae ) and the blue whale (Balaenoptera musculus) was determined by molecular biological studies, which should be therefore more closely related to these two types as with all other species of the genus Balaenoptera.

Whaling and protection

As coastal living species of the gray whale was hunted by early humans. Whether this is the reason for the very early disappearance of European stocks ( around 500 AD ), can no longer be traced. The western Atlantic gray whales became extinct around 1700. Since then, the gray whale lives only in the Pacific. The Western Pacific populations were heavily hunted in the 18th and 19th centuries by Japanese whalers. Today, it is even unclear whether the gray whales of the western Pacific still exist. Occasional sightings before the Korean coasts can also be single stray animals from the eastern Pacific. Go whale researcher at most from a population of 200 animals.

The wintering areas of the Eastern Pacific gray whales were discovered in 1846. After that whaling stations were established at the local shores and killed thousands of whales within a few years. In 1946 the species was placed under protection and so saved from extinction. Since then, stocks have grown again, so that there are about 22,000 gray whales today. But even for this small number compared to the past rich food supplies apparently no longer, as a result of the sighting of lean and apparently starving animals will be accepted. For some years are hunted inspected annually by the indigenous population of Russia about 110 gray whales.

Whalers gave the gray whales in the 19th century the nickname Devilfish. The reasons for this were furious attacks of Walkühen who wanted to protect their calves.

At the North American coast gray whales are a very popular destination for the modern whale tourism because of their coastal waters. Tourists can be brought by boat to within a few meters of the gray whales.