Orca

by George, Bank Street School for Children

Introduction

The earliest known whales lived between 40 and 50 million years ago. Their bodies were extremely long, the front limbs had already evolved into flippers for steering under water. The hind legs had become very small but they still stuck out from they body. This mammal was known as the Pakicetus, an ancestor of the whale. This ancient relative of the whale evolved from land mammals.

Food
Life Cycle
Habitat
Appearance
Behavior

Food, Eating and Hunting

Killer Whales have huge appetites. One male whale had 13 porpoises and 14 seals in its stomach. Killer Whales don't only eat whales, they also eat squid, sea elephants, seals, dolphins, narwhals, polar bears and will occasionally attack schools of salmon and tuna. Some Killer Whales need to eat three seal pups a day in order to survive. Killer Whales can tell the difference between an adult seal and a pup seal by the splashes they make.

Killer Whales are very clever hunters. They travel in schools and attack even the blue whale. They always attack in groups. Some people call the Killer Whale "wolves of the sea" because they hunt in packs like wolves. They will circle their prey and bite its stomach or make its prey open its mouth and seize its tongue. A Killer Whale will bump or tip ice floats to dislodge seals which they can easily catch in the water. Killer Whales are one of the few whales that can come up on land. They do this because they try to force seals into the water so they can kill them and eat them. They also do this to the polar bear but they have to break through the ice and sometimes they actually have to come up on the ice which is very dangerous for them.

The Killer Whale is the only natural enemy to other whales like the blue whale, and the only natural enemy of the leopard seal.

Killer Whales hunt seal by waiting until a pup seal is too far out in the ocean or does not know that the whale is there. The more experienced hunters lead the attack. The less experienced stay behind in the deeper water to catch any seal pups that might, in their panic, swim out to sea. When the Killer Whale senses the time is right, it will ride a wave in and grab the seal in its big powerful mouth. The Killer Whale will sometimes let a pup seal go and no one knows why they do this. In order to practice hunting seal, Killer Whale mothers teach their young calves how to hunt seal pups by pushing them up on the shore. They have to practice this so they don't get beached during the real thing.

Killer Whales are silent when hunting seals so they can hear the seal pups splashing in the water. Killer Whales use their sonar by listening to their own clicking sounds and their pod's (a pod is the rest of its family) clicking sounds. They listen to their prey's swimming patterns to catch them. Nothing is safe from the Killer Whale, not the smallest water bird nor the biggest whale.

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Life Cycle

Killer Whales usually have three generations of family on their pod; the grandmother, her children and her daughter's off-spring. The older bulls intimidate the younger bulls from mating with the females. A female may reach ninety years old but they reproduce slowly with a calf every eight years. Females have their first young at fifteen. A female Killer Whale is pregnant for almost a year.

Baby Killer Whales are big, they can be as long as eight feet ten inches to as little as six feet ten inches at birth. A baby Killer Whale feeds on its mother's milk for a year and may live with her pod family for its whole life. Calves shed there skin not long after birth. Even when seven years old Killer Whales stay close to their mother.

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Habitat, Environment and Shelter

Killer Whales are found in all of the oceans in the world, from the bitter cold of the Arctic to the tropical seas of the Florida keys. Sometimes when they are traveling to these places they collide with ocean going ships or get tangled in fishing nets and drown. Oil spills are very bad for Killer Whales, it pollutes the water and kills the food they eat. Killer Whales like to rub up against seaweed, and pebbles. They do this after a meal to relaxed themselves.

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Appearance

Most Killer Whales weigh up to as much as four horses put together. Some adult males can be 30 feet long and weigh up to as much as 11 tons, that's almost bigger than Jaws. Mature males have the longest dorsal fins which are usually from six feet to six and a half feet long. Female Killer Whales weigh half the size of a male, which is 4 or 5 tons. A male Killer Whale is about 32 feet long and a female is about 28 feet long. Killer Whales have excellent vision, but their eyes are very small. A baby Killer Whale has whiskers when it's born, but they fall off soon after birth.

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Life Style and Behavior

The Killer Whale is the fastest mammal in the seas. It can swim up to thirty five miles per hour. While swimming rapidly it can often make leaps forty feet long , rising four feet above the water. The Killer Whale is capable of diving to depths of over 1000 feet and it is able to remain beneath the surface for as much as twenty minutes. The Killer Whale has good eye sight but sometimes the water is so murky that they have to use their sonar. Whales talk to one another under water, they make a variety of noises and each species has its own language.

The Killer Whale is a member of the dolphin family. It is also the only member of this family that eats warm blooded animals. Killer Whales travel in packs or pods from three to fifty. In Alaska the Killers are known to follow fishing boats and gently suck the fish from the lines as they get hauled in, leaving the fishermen to pull up nothing but fish lips... yes fish lips!! Boat traffic is loud and disturbs the normal behavior the whales.

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