The Basics Belong to the oceanic dolphin family Found in all oceans Apex predators Matriarchal societies Imitate others, and teach skills to offspring
Are all Orcas the same? Three to five types of killer whales, possibly different species Resident: eat mostly fish and squid; complex and cohesive family groups; visit the same areas consistently Transient: eat exclusively marine mammals; live in groups of 2-6 individuals; less persistent family bonds Offshore: eat mostly schooling fish, may also eat mammals and sharks; live in groups of 20-75 individuals Genetic data indicate the types have not interbred in the wild for up to 10,000 years. Mitochondrial DNA sequences support that there are many newly diverged species within the orca category. First split was about 700,000 years ago
Specs Largest living members of the dolphin family Males range 20-26 ft. long and weigh >6 tons Females range 16-23 ft. and weigh 3-4 tons Newborn calves are about 400 lbs. Able to reach speeds in excess of 56 km/h Live an average of 40 years in wild; average of 25 years in captivity Total population is >50,000
Fish are Food, Not Friends Hunt in packs Different populations specialize eating different kind of prey. Eats 500 lbs. of food per day Carousel feeding: use bursts of bubbles or flash white underbelly to herd fish into a ball, which they then slap with their tails to stun or kill fish Sharks: herd them to the surface and strike them with their tail flukes Know how to induce tonic immobility in sharks and rays by holding them upside down Whales: separate whale calves from mothers Sometimes harass or kill other animals for no known reason
Sonar Fun Fact: Dolphin’s sonar is not reflected by fishing nets. This is why they get stuck in nets so often. Fatty melon and bottom jaw absorb reflected waves Do not like U.S. Navy sonar
Orca Care Orcas must be watered at least once per week. As of August 13, 2013, there are 45 orcas in captivity worldwide, 32 of which are captive-born. The Alliance of Marine Mammal Parks and Aquariums (AMMPA) goes further, and recommends 1,918 m 3 for two killer whales. US regulations require 615 m 3 for two killer whales. That is 48 feet long and 12 feet deep. Dorsal fin collapse Make sure to vaccinate!
Thoughts? Who has seen Free Willy? Why should or should not orcas be kept in captivity? Do you think orcas have cognitive abilities comparable to those of humans? Should intelligent animals be given human-like rights under the law? Should we build orcas reverse SCUBA suits so they can study our societies?