Orca (Orcinus orca)
Classification -
Morphology -
Symmetry - bilateral
Structure - The group structure of the orca can be quite complex. For example, in ‘resident’ orcas, the basic social unit is a matriline, consisting of a mature female, her adult offspring, and her daughters’ offspring, with individuals in this group having very strong bonds and staying in the group for life, although they mate outside of it
Appearamce - The orca’s strikingly marked black and white body is unmistakable, being black on the upperparts, sometimes with a light grey ‘saddle patch’ behind the dorsal fin, and white on the underparts, lower jaw and undersides of the tail.
Structure - The group structure of the orca can be quite complex. For example, in ‘resident’ orcas, the basic social unit is a matriline, consisting of a mature female, her adult offspring, and her daughters’ offspring, with individuals in this group having very strong bonds and staying in the group for life, although they mate outside of it
Appearamce - The orca’s strikingly marked black and white body is unmistakable, being black on the upperparts, sometimes with a light grey ‘saddle patch’ behind the dorsal fin, and white on the underparts, lower jaw and undersides of the tail.
Biology -
The orca is the world’s largest predator of warm-blooded animals, and the only cetacean to routinely hunt marine mammals (5), including seals, sea lions, dolphins and sea otters. The orca will even kill large whales, and also hunts fish (including sharks and rays), squid, octopuses, sea turtles and seabirds, such as penguins
Distribution Map -
Importance -
They help to keep the ecosystem in check by eating certain animals, and keeping their population in check.
Facts -
Male orcas reach sexual maturity at around 15 years, but do not become physically mature until about 21, while females reach sexual maturity in their early teens. Breeding can occur at any time of year, although in the northern hemisphere births usually peak between October and March. The female orca gives birth to a single calf after a gestation period of around 15 to 18 months, and the calf is weaned at 1 to 2 years old. Although potentially living for up to 90 years, a female orca only produces a calf once every 3 to 8 years, up to the age of about 40. After reaching 40, the female ceases to reproduce, but may instead take on a role as a ‘grandmother’, passing on important experience to younger relatives.
Vocabulary -
CetaceansA group comprising all whales, dolphins and porpoises.Dorsal finThe unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.EcholocationDetecting objects by reflected sound. Used by bats and odontocete cetaceans (toothed whales, dolphins and porpoises) for orientation and to detect and locate prey.GestationThe state of being pregnant; the period from conception to birth.Pectoral finsIn cetaceans (whales, dolphins and porpoises), the paddle-like pair of limbs, also known as ‘flippers’, found on either side of the body and used for balance and steering.
Resources -