Killer Whales Essays (1605 words) - Biota, Megafauna, Apex Predators

Killer Whales Whales are giant creatures that live in the sea. They look like fish, but are not. Whales belong to the group of animals called mammals. Whales belong to the group of mammals called cetaceans, which comes from a Latin word meaning large sea animal. There are two major groups of whales. The first group is mysticeti (baleen whales), and the other isodontoceti (toothed whales). In the group odontoceti, there is a family of whales called delphinidae (dolphins and small toothed whales). In this report, I will focus on a species of whale that comes from this family, and that species is the killer whale, or also known as orcinus orca, or just orca. The largest and most striking of the dolphin family, the killer whale is one of the most fearsome predators of the deep. Killer whales are basically the same shape as fish, but they differ in many ways. One of the most obvious differences is the tail fin. Fish have vertical tail fins, while whales have horizontal tail fins. One of the most distinctive features of orcas is the tall, wide dorsal fin located on its back. In females, the dorsal fin can grow to about 2 feet high. It is falcate (hooked or curved). In males, the dorsal fin is triangular in shape and can grow up to about 6 feet high. Another distinctive feature of killer whales is that they possess a sleek, black and white pigmentation pattern. A white patch is located above and behind the eye. An extensive white ventral patch extends onto the flanks (sides). "There is a gray saddle behind the dorsal fin, which is black at birth." (Hoyt, Pg. 32) At birth, orcas are about 2.1 to 2.4 meters long and weigh about 180 kilograms. When they are adults, males grow to about 9.5 meters long weighing 8 tons or more. Females grow to 8.2 meters long and weigh 4-6 tons. "Orcas have robust and graceful bodies with a conical or rounded head." (Hoyt, Pg. 97) It has no distinct beak. They have straight mouthlines. Another physical attribute of killer whales, besides having a tall dorsal fin, is that killer whales have large, paddle-shaped flippers. These flippers are 2-3 times larger in males than they are in females. Killer whales are very large physical specimens. Being known as a fearsome hunter with killer instinct, it would be interesting to know what a killer whale's diet consists of. The orca resembles the great white shark in its predatory skill and range of food. They eat seabirds, turtles, fishes, including sharks, whales, dolphins, porpoises, seals, and sea lions. These hunters feed in groups of two to twenty animals. They can even kill baleen whales much larger then themselves. They have 10 to 13 teeth on each side of each jaw, which helps in their feeding. Though killer whales sometimes attack dolphins, seals, and other whales larger than themselves, but they have not been known to attack people, although there have been documented cases of killer whale attacks. Throughout the ages, whales have lost some of the characteristics of mammals. Mammals have hair covering their bodies. Whales have only a few stiff hairs on their heads. Mammals have four legs. A whale has no hind legs. The only traces that they remain are two tiny hipbones. The front legs have developed into flippers, which are used for steering or keeping its balance. Although killer whales share the same characteristics as mammals, they also have special features that allow them to live in the water. Whales have many special characteristics suited for living in the water. Living in water enables them to reach enormous sizes. "The buoyancy (lift) of water helps support a whale's body, which makes it possible for them to grow larger." (Ellis & Knoph, Pg.18) Orcas have a highly streamlined shape. This enables them to swim with a minimum of resistance. The powerful tail fins called flukes are horizontal. Whales swim by moving the flukes up and down. Another characteristic that is helpful to killer whales, or any type of whale, is that a whale's backbone, ribcage, and shoulder blades resemble those of other mammals. Almost all mammals have seven neck vertebrae. In killer whales, these vertebrae are compressed into a short length or joined together into one bone. This keeps the head from moving about. It also joins the head directly to the body. Orcas have smooth, rubbery skin that easily slips through the water. Mammals have hair to keep them warm. Whales have only a few