![]() These factors combined mean that killer whale populations tend to have extremely low growth rates, which cam make any factor that increases the death rate by even a small amount a severe threat to the population. Those who do survive their first six months generally live between 30 years (for males) and 50 years (for females). ![]() It is difficult to measure how many perish either neonatally or within the first few months of life a very rough estimate suggests that nearly half do not make it to adulthood. While whales have no natural predators, calves are vulnerable during infancy. Back to top Breedingįemales don’t give birth to their first calf until they are about 15 years old and they calve only once every five years on average. This research reveals the devastating consequences of an imbalanced food web in the wild, and the crucial interdependency of Canada’s diverse marine species. Similar patterns are beginning to appear in transient (mammal-eating) killer whales over a longer period of time. The opposite is true of years when the salmon supply falters. In years when the salmon supply is good, whale populations produce more births than deaths. Recently, researchers on Canada’s west coast have been probing the close relationship between chinook salmon populations and the rate of resident killer whale mortality. However, because they tend to spend time in water less than five metres deep, often foraging in inter-tidal areas at high tide, transient whales have been known occasionally to eat animals such as deer, moose and pigs. Transient killer whales eat mainly other marine mammals. The preferred prey of the offshore population of killer whales is not known, but is likely fishes. Northern and Southern resident killer whales, however, eat mainly fish. Throughout their world-wide range, killer whales eat a wide variety of prey, including squid, fish, sea turtles, sea birds, sea and river otters, sea lions, penguins, dolphins and other large cetaceans, such as the blue whale. Some individuals have been sighted as far south as central California and as far north as Alaska. The offshore population is small and is poorly studied. Southern residents are found off southern Vancouver Island. The northern community lives off northern Vancouver Island and the mainland coast. Resident killer whales live in separate northern and southern communities. They have been seen in water ranging from shallow (several metres deep) to open ocean depths. Killer whales are not limited by such habitat considerations as depth, water temperature or salinity. In British Columbia, they have been seen throughout almost all marine areas including many inlets and narrow channels. They tend to concentrate in colder regions and are found in all of Canada’s oceans, as well as occasionally in Hudson Bay and in the Gulf of the St. The killer whale is a cosmopolitan creature, having been observed in oceans all over the world. Called echo-location, this natural sonar is useful when searching for food or navigating in murky water, enabling the whales to build an accurate picture of what’s around them. They use a series of clicking sounds that bounce off fish and other objects in the water. ![]() Killer whale pods are very vocal when hunting for prey. Pods of whales with similar dialects are called clans. Researchers have shown that the more similar the dialects between two pods, the closer they are related. ![]() Killer whales can recognize their own pods easily from several miles away based on distinctive songs. The sounds vary from pod to pod, with each group having its own unique dialect. Killer whales communicate with each other through a complex variety of whistles, squeaks and whines produced in special air-filled nasal sacs well below the blowhole. Killer whales of both sexes often remain with their parents for life. Pods occasionally mix to form groups of well over 100 individuals, though this amalgam is only temporary. The internal social structure of a pod remains unclear to scientists, though we do know that they usually consist of 10 to 40 whales. The largest members of the dolphin family, killer whales are highly social animals that live in stable, family-related groups called pods. The shape of the dorsal fin and saddle patch, as well as natural nicks and scars on them, are unique to each killer whale. Behind the dorsal fin is a grey area called a saddle patch. In females and young whales, the fin is curved and less than one metre high. In fully grown males, this fin sticks straight up, often as high as 1.8 metres. The first sight of a killer whale is often the tall dorsal fin. Its size - six to eight metres long and between four and five tonnes in weight - and its striking black-and-white colouring, and long, rounded body make it unmistakable. Without a doubt, the killer whale (Orcinus orca) is one of the most distinctive marine mammals in the world.
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