Teacher Background Material

Whales, dolphins and porpoises belong to a group of animals called cetaceans. 

Life Cycle of the Whale:

A whale baby is called a calf, the mother is a cow and the father is a bull. Whales usually have one baby at a time. The whale calf is born under water with its eyes open and ready to swim. The calf must go to the surface as soon as it is born in order to breathe. The mother helps the baby to the surface to take its first breath of air.

A whale calf grows very fast. Mother whale has nipples hidden on the grooves on her belly. When the calf is hungry, it bumps its mother. She squirts milk into the baby's mouth. The baby whale can drink many gallons of milk in a short time. Whale milk is very rich. It looks more like cream that the milk we drink. Cow milk is 4% fat, while whale milk is more that 50% fat. Because the food is so rich, a whale calf grows very fast. A blue whale calf gains over 4 kilograms/8 lbs. each hour until it is several months old. The whale calf will stay with its mother until it is able to find its own food.

Echolocation:

It is hard to see very far under water. Light does not travel well through water, so the deeper you go, the darker it becomes. Water is a good carrier of sound. In fact sound travels faster and farther in water than in air. Some whales have learned to "see" with sound. This is called echolocation. The whale sends out a sound. When the sound hits an object such as rocks or a school of fish, it bounces back toward the whale. The whale can tell how far off the object is by how long it takes the sound to bounce back. Using echolocation helps these whales to find food and to avoid dangerous places.

Migration:

Many whales migrate from their cold homes to warmer areas to mate and give birth to their babies. For example, each year California grey whales migrate from the Arctic down to Mexican waters. The gray whales spend the summer in the Arctic, swimming in the Bering and Chukichi Seas along the coast of Alaska and Siberia. When the weather begins to get chilly, the start down the Pacific coast. Late in December, the whales arrive off Baja California where they give birth to their babies. When spring arrives they head back north with their calves. 

This is a long journey. It is more that 5,000 miles from the Arctic to the warm Mexican waters. The grey whale swims along at about 4-5 knots. This is about 6 miles per hour. It takes them about 3 months to travel each way.

Toothed and Baleen:

Whales are divided into groups by the way they catch their food. The two groups are the baleen whales and the toothed whales. Baleen whales have special plates growing from their upper jaws. These plates are made of a material like your fingernails. The plates are in strips hanging down into the whale's mouth. The baleen strains food out of the water. Plankton and krill are the main food sources. Plankton are very small plants and animals that live in the sea. A huge whale might eat several thousand pounds of plankton in a day. Two examples of baleen whales are the grey whale and the humpback whale.

Toothed whales must chase and catch their food. They catch their food one piece at a time, usually eating fish, squid or shellfish. Their sharp teeth are not used for chewing up food. The teeth grip the food while the whale tears its prey apart. Sometimes toothed whales swallow their food whole. The different toothed whales have teeth to fit their own needs. For example, the killer whale has alternating teeth in its upper and lower jaws. When the killer whale closes its mouth, the teeth form a trap holding its prey securely. Some examples of toothed whales are: sperm whale, killer whale, bottlenose, and narwhal.

There She Blows!

A whale's nose is called a blowhole, which is located on the top of a whale's head. When a whale breathes out, it makes a cloud called a blow, spout, or spume. Different kinds of whales have different kinds of spouts.

Whale Origins:

By studying ancient fossils and unborn baby whales, scientists think that whales have not always lived in the sea. Millions of years ago the ancestors of whales lived on land. They had four legs and were covered with fur. Over the years they moved further and further out into the ocean searching for food. Over millions of years their bodies changed into the sea mammals we see today. Some changes are:

Endangered:

Although many whales are near extinction, there are still people who hunt them. Many groups of people are working to see that whale hunting ends. There have been laws passed to see that this happens.

Species:

Following is a list of some whale species that can be used for child research. Additional species should be added to your list. If you wish to contribute more species to this list, contact the webmaster.

Sizes:

Whale Internet Links

Clip Art:

Copy and paste these images into student handouts or research booklets and size according to your need.