Killer whales have not been as directly impacted by human exploitation as other whale species. They are occasionally hunted but management of harvests seems to have been effective. The fossil history of killer whales dates to the Pliocene epoch, about 5 million years ago.
The fossil history is not rich, but some finds link Orcinus orca to its early ancestors. Teeth, partial skulls, jaw bones, and periotic bones found in a mammal's ear have been found and identified in many countries of the world, including: Japan, Hungary, Italy, and South Africa. Heyning and Dahlheim, It is the second largest ocean in the world after the Pacific Ocean.
Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria. Found on all continents except maybe Antarctica and in all biogeographic provinces; or in all the major oceans Atlantic, Indian, and Pacific. The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a now extinct synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds. Iteroparous animals must, by definition, survive over multiple seasons or periodic condition changes. An aquatic biome consisting of the open ocean, far from land, does not include sea bottom benthic zone.
Bower, B. Culture of the Sea. Science News , Vol. Chadwick, D. Evolution of Whales. National Geographic , Vol. Deeke, V. Ford, P. Estes, J. Tinker, T. Williams, D. Science, New Series , Vol. Demaster, D. Doak, T. Williams, R. Brownell, Jr.. Whales, Whaling, and Ocean Ecosystems. Ford, J. Ellis, K. Killer Whales. University of Washington Press , unknown: Heintzelman, D. Tulsa, Oklahoma Winchester Press. Heyning, J. Orcinus orca. Mammalian Species , Mann, J.
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Steinman, S. Gearhart, J. Although orcas tend to aggregate in cold water, they live in all the world's oceans, from the Antarctic to the tropics. Unlike other whales that follow predictable seasonal migration patterns, orcas tend to go wherever their food source is, making their movement patterns much less predictable. Salmon or herring migrations seasonally influence the distributions of some orcas.
Other orca ecotypes e. The life cycle of orcas is similar to that of humans. Female orcas become mature around age Among the Southern Resident orcas, the youngest known mother is J Mating and calving take place year round. Gestation varies from 15 to 18 months. Females attain sexual maturity in their early teens. The average birthing rate now one viable calf per female every 9 or 10 years. Females are reproductive until about age Calves will typically nurse until age two but will begin to eat some solid food around age one.
The average lifespan of female orcas in the wild is 50 years, with several individuals living as long as 80— years estimated. Between ages 12 and 15, their dorsal fin begins to grow taller and straighter, indicating the onset of sexual maturity. Males in the wild live 29 years on average, to a maximum of 50—60 years. J1, who died in , was estimated to be 59 years old. Designated endangered in Canada in ;. The Latin name is Orcinus orca.
Common names are orca or killer whale, while other names include blackfish, grampus, and killer. Most English-speaking scientists use the name killer whale, although orca is increasingly used, in particular by the general public.
The species name in Latin, orca, literally means "the shape of a barrel or cask," likely due to the orca's body shape. This term is thought to be borrowed from the Greek word that was commonly used to refer to whales.
Orcas are the largest members of the dolphin family. Orcas are the largest members of the dolphin family. Males are bigger than females, but they vary in size and weight, depending on the type of orca. The largest orca ever recorded was a staggering 32 feet 9.
That's longer and heavier than most motorhomes. Orcas are known for their long dorsal fin the fin on the animal's back and black-and-white coloring.
The black-and-white coloring helps to camouflage them by obscuring their outline in the water. Just behind the dorsal fin is a patch of gray called a "saddle" — because it looks like a riding saddle. An orca's body is cylindrical and tapers at each end to form a hydrodynamic shape.
Orcas have massive teeth, which can grow up to 4 inches 10 centimeters long, according to National Geographic. Orcas are apex predators, at the top of the food chain. No animals hunt orcas except for humans. Killer whales feed on many different types of prey, including fish, seals , sea birds and squid. They can also take down whales larger than themselves, such as minke whales, and they are the only animal known to predate on great white sharks, according to The Natural History Museum in London.
Killer whales have even been reported to kill swimming deer and moose , according to a chapter on orcas in " Primates and Cetaceans " Springer, Orcas use many different techniques to catch prey. Sometimes they beach themselves to catch seals on land, jumping from the water onto land. They can use echolocation to identify their prey by creating sounds, or sound waves, that travel through the water. These waves echo off objects, including prey, which the orcas can use to locate them, according to SeaWorld.
There is no record of an orca ever killing a human in the wild. This is because humans are not part of their natural diet. Occasionally, an orca may mistake a human for something they do eat, such as a seal. In , an orca was caught on camera charging at a surfer during the Lofoten Masters surfing competition in Norway. The orca seemed to pull out of the attack just before making contact. The Norwegian Orca Survey said in a Facebook post that the orca likely realized the surfer was not a seal at the very last second.
In , a year-old boy was "bumped" by a killer whale near Ketchikan, Alaska, in what may have been an aborted attack — similar to the surfer in Norway — or simply curiosity on behalf of the orca, according to the Associated Press, via The Seattle Times. The Associated Press reported that a surfer was bitten in California in the early s, which is the only relatively well-documented case of a wild orca actually biting a human.
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