One species of mammal is Orcinus Orca also known as the killer whale, orca whale, or blackfish. Even though commonly referred to as a whale, orcas are actually more closely related to dolphins and other porpoises. Belonging to the family delphinidae, Orcas are the only extant species in their genus orcinus.
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Orcas live in all the oceans in the world, however they tend to prefer 20-60 meter depths. Some orcas will dive up to 300 meters to find food. Orcas are on the top of the marine food chain, being a social hunter means they will hunt in groups referred to as pods of up to 50. Orcas will eat many things including seals, sea lions, smaller whales and dolphins, fish, sharks, squid, octopi, sea turtles, sea birds, sea otters, river otters, and other animals. Orcas are able to dive to such a depth because of their ability to hold their breath for hours at a time.
Orcas reproduce sexually, becoming mature at between 6-10 years in females, and 10-13 years in males. Gestation takes 14 months, and produces one live birthed fully formed calf. There is usually only 1 offspring which nurses for 1 year. Orcas are good parental figures taking care of the young. Most orcas live for about 63 years for females, and 36 years for males.
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Orcas move through the water using their tail, pivoting it in an up and down motion, changing direction requires the use of 2 fins on the sides, and the dorsal fin. Orcas can charge through the water at speeds of up to 30 mph, however they normally cruise around 2-6 mph.
Another species is Monodon Monoceros or Narwhal. This species belongs to the order cetacea,
and the family monodontidae. Narwhals are a large aquatic mammal also, however there are many differences. Narwhals have only two teeth, both being in the upper jaw. One of these teeth(usually the left) will normally protrude from the upper lip creating a large horn that spirals in a counter clockwise direction. Sometimes reaching 3 meters in length the purpose of this tusk is unknown, scientists believe it may be used as defense or for mating attraction. Sometimes both teeth will protrude, however they always turn in the same direction.
Not much is known about narwhals, as they are almost always under pack ice above the arctic circle, between Eastern Canada and Central Russia. Their mating system is unknown, but they do have sexual reproduction and internal fertilization. The gestation period is about 15 months usually producing 1 calf. they reach sexual maturity at about 4-7 years of age. The young are taken care of for an extended period of time by the mother, and are usually quite safe in their pod. Narwhals will live for 50+ years in the wild, but will die after only 1-4 months in captivity.
Narwhals keep their prey species limited in population, including squid, fish, and crustaceans. They were regarded largely as a great food resource by the inuit people who would hunt them in small boats for their fat (blubber) which could be used as lamp oil, their meat for food, their ivory tusks, and their skin which is very valuable. As all ivory bearing mammals they are a near threatened species. Narwhals move very similarly to the killer whale, using an up and down motion of their larhe fluked tail.
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Another species is Monodon Monoceros or Narwhal. This species belongs to the order cetacea,
and the family monodontidae. Narwhals are a large aquatic mammal also, however there are many differences. Narwhals have only two teeth, both being in the upper jaw. One of these teeth(usually the left) will normally protrude from the upper lip creating a large horn that spirals in a counter clockwise direction. Sometimes reaching 3 meters in length the purpose of this tusk is unknown, scientists believe it may be used as defense or for mating attraction. Sometimes both teeth will protrude, however they always turn in the same direction.
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| http://icestories.exploratorium.edu/dispatches/wp-content/uploads/2008/05/courtesy_whale_release_and_stranding_group.jpg |
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