Killer+Whales

=Title: Killer Whales=

Basic Information
The //Orca//, or "Killer" Whales are the largest members of the dolphin family. Killer Whales have long, rounded bodies with dorsal fins at the middle of their backs. Their black bodies are marked with white patches on the underside and near the eyes. Its species name according to Linnaean binomial is //Orcinus orca.//


 * < Domain ||< Eukarya ||
 * < Kingdom ||< Animalia ||
 * < Phylum ||< Chordata ||
 * < Class ||< Mammalia ||
 * < Order ||< Cetacea ||
 * < Family ||< Delphinidae ||
 * < Genus ||< Orcinus ||
 * < Species ||< orca ||

Habitat
Open tropical, temperate, and polar seas are home to the Killer Whales. They mostly live in the cold waters of the Northern Pacific and Atlantic Oceans and the Arctic Sea. They are also often found off the Western coast of North America, near Alaska and British Columbia. Killer Whales also live South of Africa and Australia in the cold Arctic Seas and Tropics. Occasionally, Killer Whales take swims in fresh water but they don't tend to live there. It also occasionally may swim into bays and estuaries. Sightings range from the surf zone to the open sea, though usually within 800km of the shoreline. Resident killer whales in the Pacific Northwest waters use regions of high relieve topography along salmon migration routes, whereas transient whales forage for pinnipein in shallow protected waters.
 * Killer Whale Range Map**

Physiology
Killer whales are among the fastest swimming marine mammals. Their bodies are tapered at both ends which helps them to have control as they move through the water. They have one dorsal fin and a fluke at the end of their body on the back that allows them to navigate direction in the water. The size and shape of the dorsal fin and the fluke are different for each Killer Whale. Their body is spindle shaped with the tapers at both ends to help them get through the water easily. They are heavy animals so these help them conserve energy while swimming. It is believed their coloring allows them to easily reach prey without being identified. The movement of the white and black colors as they move help to camouflage them. Killer Whales have very powerful jaws and very sharp teeth. The sharp teeth allow them to easily rip their prey down into chunks they can swallow with ease. They have great eyesight as well as hearing which allow them to easily move around in the water during the day and at night. They can pick up vibrations in the water that help them to identify threats and to find their prey. When swimming near the surface, a killer whale usually stays below water for 30 seconds or less. A killer whale breathes through a single blowhole on top of its head, the blow whole is in a relaxed position and opens and closes to intake oxygen. The visible spout of water that rises from a killer whale’s blowhole is not coming from the lungs, which do not tolerate water.

Species Interaction
Killer whales are well-known as predators of other marine mammals, including the large sperm and baleen whales. Members of all marine mammal families, except the river dolphins and manatees, have been recorded as prey of killer whales. Killer whales are more important predators for some populations than previously believed, for example: sea lions, and penguins. Within the last few years, small populations of killer whales that could not find enough food due to overfishing have started preying upon sea otters. That has resulted in otter populations decreasing and an increase in sea urchins who are eating away all the kelp forests in the ocean. The killer whale  has a complex history of  interaction  with  humans. Although there have been only a few recorded attacks of wild orcas on humans , the species has long been feared for its coordinated hunting abilities. Killer whales can induce tonic immobility in sharks and rays by holding them upside down, rendering them helpless and incapable of injuring the whale.

Reproduction
In the winter the families of killer whales migrate to warmer waters and usually have their babies in the warm waters. Females become sexually mature when they reach about 4.6 to 4.9 m (15–16 ft.), at about 6 to 10 years. While males become sexually mature when they reach about 5.5 to 6.1 m (18–20 ft.), at about 10 to 13 years.In males, dorsal fin growth is probably a secondary sex characteristic. Peak growth of the fin coincides with the onset of sexual maturity.Male killer whales in the wild may not successfully reproduce until they are much older, larger, and able to compete with other males. Females come into estrus or “heat” several times during the year. Killer whales undergo periods of multiple estrous cycling (polyestrus), interspersed with periods of non-cycling. On average, females may have four estrous cycles during one polyestrus period. This period is highly variable, as is the period of non-cycling, both for one whale over time, and between whales. Killer whales are polygamous: they mate with several partners.

Free Topic- Conservation Efforts
Even though Killer Whales have never really been hunted in large numbers, there are many precautions being taken by ecologists and scientists to prevent it from becoming endangered like its ocean cousins Chinese White Dolphin and Whales. Global Warming and Pollutions are a major reason to why their numbers are decreasing. Both natural toxins and human-made toxins can harm killer whales. For example: PCB's (polychlorinated biphenyls) is a type of organochlorine,which a group of environmental pollutant which is being released into the ocean. PCB concentration increases with age in male killer whales and in sexually immature females. On the other hand, reproductively active female killer whales showed lower PCB levels than did adult males or sexually immature females. A mother killer whale transfers PCBs to her calf as the calf develops and also through fat-rich milk as the calf nurses. IUCN/The World Conservation Union is a worldwide conservation organization and they have a Red List system for assessing an animal’s relative risk of extinction. Its goal is to categorize and raise global awareness of species that face a high risk of extinction. The killer whale is categorize in it. America has also taken upon itself to help not only Killer whales but all of the marine mammals. Some examples are: The U.S. Marine Mammal Protection Act (MMPA) of 1972 made it illegal to hunt or harass marine mammals in the U.S. Also the Endangered Species Act of 1973 (ESA) conserves endangered species and their ecosystems. Killer Whale populations are closely monitored as well.