Killer whales, often known as Orcas, are a very vulnerable type of mammal. They are the largest members of the dolphin family, which includes some creatures with whale in their name, like long-finned pilot whales, dolphins and porpoises alike. Like us killer whales cannot breathe underwater but, unlike us, they can hold their breath for up till an hour. They can swim up to 55 kilometres per hour and they can live for 50 to 80 years (in the wild that is) but, in captivity, their lifespan lowers drastically to 10 years - if that!
								Killer whales travel around in family groups called 'pods' and will stay in the same group for life. They will also swim onto beaches to catch their prey but they do this very rarely because they usually get stranded. Most of the time they find food by a tactic called 'echolocation', which is when the whale produces a noise and waits for the echo to bounce back. This helps them to locate their prey. Often the pods work together to catch their food. Orcas don't breed until they are about 15 years old and stop breeding when they are roughly 40 years old. Females tend to live longer than males. A young killer whale is called a calf. When the killer whale is born it is already one-third the size of its mother. After that males can grow up to 23 feet long and weigh up to 9 tons whereas the females grow to 21 feet long and weigh 5 tons. They have a long, rounded body with a large dorsal fin on their back. They have black bodies and white patches on their belly and above the eye. The only predator for adult killer whales is man. These great mammals, as well as many other marine species, are suffering a lot because of man's greed and the heavy amounts of pollution dumped in the water. In some countries killer whales are being killed for meat even though their flesh is far from highly prized to the point where some people consider them unsafe for us to eat. Some individuals have had very high concentrations of toxins in their body, which is only to be expected considering the extent of pollution and their position at the top of the food chain. Lots of the fish that killer whales eat are very polluted. If killer whales eat them they might die while their numbers could soon be unsustainable and they may become extinct. Scientists found out that killer whales are 500 percent higher in toxic waste levels than those that they found in humans. In many cases their calves are born already contaminated.