Blue Whale Basics
Imagine an animal so large that its heart weighs as much as a small car. Picture it pushing thousands of pounds of food down its throat with a tongue that weighs as much as an elephant. This may sound like science fiction, but it's reality for the massive blue whale.
The blue whale is the largest animal in the history of the world. It can grow to a length of 100 feet and 200 tons. It has a long, blue-gray body with a small dorsal fin on its back. The blue whale uses its tail fin, called the fluke, to swim through the ocean at speeds of over 20 miles per hour.
Blue whales do not breathe through gills like fish--they use lungs to breathe air at the surface of the ocean. Many people think whales blow water out of their blowholes, but it's really just air mixed with a little water from the surface.
The Lives of Blue Whales
Blue whales are found in oceans all over the world, usually in groups called pods. They spend summer near the poles, where they can easily find food. Winter is spent in warmer waters, where they mate.
Females give birth to single babies, called calves. These calves are some of the biggest babies on the planet! A newborn calf is up to 25 feet long and 3 tons. It gains 200 pounds a day for the first year of its life just by drinking its mother's milk.
Nobody knows exactly how long blue whales live, but scientists believe they live more than 50 years. They have few predators but are occasionally attacked by killer whales and sharks.
A Very Tiny Meal
Despite their enormous size, blue whales feast on some of the tiniest animals in the sea: shrimp-like animals called krill. That's because they don't have teeth. Instead, they use rows of bristles on their upper jaws, called baleen. The whale opens its wide mouth and takes in thousands of gallons of water. Then, the whale strains the water out through its baleen and eats the krill left behind.
Blue whales can eat 8,000 pounds of krill each day. They need these huge meals because they go for several months without eating during breeding season. And since they burn about 3 million calories per day, they really need to store their energy!
Saving the Whales
Scientists believe there are 10,000-25,000 blue whales alive today. That sounds like a lot, but there used to be over 300,000! How did so many disappear?
Blue whales became popular with hunters in the 1900s. These hunters, called whalers, killed the whales to sell the oil, blubber, and meat from their bodies. Blue whales almost went extinct, or disappeared, because of whaling.
It's now illegal to hunt blue whales, but they still face risks from large ships and fishing gear entanglement. Blue whales are listed as an endangered species because there are so few of them left, and scientists and activists work to protect the whales and their habitats.
Blue whales swim in the world's oceans and are the largest animals ever to have lived. They generally live in groups called pods, and they eat by straining krill from the water using their baleen, which are rows of bristles on the upper jaw. The blue whale is now listed as an endangered species.
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Blue Whales: Fill-in-the-Blank Activity
This activity will help you assess your knowledge of the diet, habitat, and status of blue whales in our vast oceans.
For this activity, print or copy this page on a blank piece of paper. Use the words presented in the word bank to complete the sentence. Neatly write them on the appropriate blank space provided.
- Blue whales are named for their __________ to blue skin coloration, which appears true blue underwater.
- Blue whales can reach a length of 100 feet and a weight of 200 tons, making them the __________ animal on the planet.
- The bony material that makes up the plates in the upper jaw of a blue whale is called the __________.
- __________ refers to a species of small, shrimp-like organisms that serve as the major food source of whales.
- __________ is the process of hunting whales for their usable products such as meat and oil.
- Whales are a widely distributed and diverse group of fully aquatic animals, which breathe air through their __________.
- A baby blue whale depends primarily on its mother's __________ for survival.
- __________ strikes and __________ entanglement are significant mortality factors for blue whales.
- Blue whales are formally classified as __________ animals by various international organizations.
- Some animals, including the blue whale, can go for several months without eating during the __________ season.
- Ship, Fishing gear
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