Whale

Whales are large animals that live in the ocean. They are part of a group called cetaceans, which also includes dolphins and porpoises. Whales range in size from small to very large. The blue whale is the biggest animal that has ever lived.

Some whales, like the humpback whale, eat tiny animals called krill and plankton using special plates in their mouths called baleen. Other whales, like the sperm whale, have teeth and eat fish and squid. All whales need to come up to the surface to breathe air through holes on the top of their heads.

Whales were hunted in the past, but rules now protect most of them. They can still get hurt by getting stuck in fishing nets or by pollution. Many people enjoy watching whales, and it has become a popular activity to see them in the ocean.

Etymology and definitions

The word "whale" comes from the Old English word hwæl, meaning "large sea fish". This word is not related to the country of Wales.

Sometimes people use "whale" to talk about dolphins and porpoises too. Some dolphins, like the orca or killer whale and the melon-headed whale, have "whale" in their names. There are special groups of whales called "Great Whales", which include big whales like sperm whales and blue whales.

Taxonomy and evolution

See also: List of cetaceans and List of extinct cetaceans

Phylogeny

Whales are a type of mammal in a group called Laurasiatheria. They belong to a group known as Cetacea, which also includes dolphins and porpoises. There are two main kinds of whales: baleen whales, who use a special sieve-like structure to catch food from the water, and toothed whales, who have sharp teeth for catching prey.

Evolution

Main article: Evolution of cetaceans

Whales started out as land animals related to even-toed ungulates, like the Indohyus. About 48 million years ago, they began living in the sea. Over time, they changed to help them swim and live underwater, such as getting a smooth body shape, tail flukes, and blowholes on top of their heads. Today, hippopotamuses are the closest living relatives of whales. The two main groups of whales, baleen and toothed, separated about 34 million years ago.

Biology

Whales are large, fully aquatic mammals with torpedo-shaped bodies. They have non-flexible necks, flippers instead of limbs, and large tail fins. Their skulls are flat with small eye orbits and eyes on the sides of their heads. Whales range greatly in size, from the small dwarf sperm whale to the enormous blue whale, which is the largest creature on Earth.

Whales breathe through blowholes on top of their heads, releasing a spout of air before inhaling fresh air. They have thick blubber for insulation, protection, and energy storage. Their teeth or whalebone (depending on the species) are specially adapted for their diet. Whales use their flippers for steering and their tail fins for propulsion, allowing them to swim at high speeds. They can dive deep by slowing their heart rates and storing oxygen in special body tissues.

Whales have adapted ears for underwater hearing and can produce a variety of vocalizations, including loud songs and clicks used for communication and navigation. Many species display intelligent behaviors such as teaching, learning, and cooperating. They give birth to live young and nurse their calves with rich, fatty milk. Most whales migrate long distances between feeding and breeding grounds. Unlike many animals, whales must stay conscious to breathe, and they have special ways of resting without drowning.

Main article: Cetacean intelligence

See also: Cetacean surfacing behaviour

See also: Right whale § Courtship and reproduction

Further information: Sleep in animals

Ecology

Whales are animals that eat meat. Some whales, like the blue whale, eat tiny sea creatures called krill. Others, like the sperm whale, eat squid. Whales usually hunt alone, but sometimes they hunt in small groups.

When whales die, their bodies sink to the deep ocean. This gives a home to many sea creatures and helps many different kinds of marine life for years. This process is called a "whale fall."

Relationship with humans

Whaling

Main articles: Whaling and History of whaling

People have hunted whales for a very long time. Early hunters used tools called harpoons to catch whales from small boats. Many different cultures, like the Inuit and the Basques, had their own ways of hunting whales. In the 1700s and 1800s, whaling became a big business because people wanted whale oil, baleen, and ambergris. Today, only a few places still hunt whales, and some groups do it to get food.

Other threats

Further information: Cetacean bycatch, Cetacean stranding, and Marine mammals and sonar

Whales face many dangers from people. They can get stuck in fishing nets, which can hurt or kill them. Pollution, like chemicals and plastic, also harms whales. Loud sounds from ships, called sonar, can bother whales and sometimes make them come ashore. Whales can also get into accidents with big ships, especially animals like the North Atlantic right whale.

Conservation

People have been working to protect whales since the middle of the last century. The International Whaling Commission has made rules to limit whaling and created safe areas for whales. Some whale groups are getting bigger, but others are still in danger. Changes in the world's climate are also a new problem for whales, especially those that live near the poles.

Whale watching

Watching whales has become a favorite activity for tourists, with millions of people doing it every year. This helps many communities make money, but it is important to do it carefully so we don’t bother the whales. When done the right way, watching whales can help protect them too.

In myth, literature and art

Further information: Biomusic § Whale song in music

Whales have inspired people for thousands of years. They appear in old stories, religious tales, and many books and movies. For example, the story of Jonah and the whale is famous, and whales continue to fascinate people all over the world.

In captivity

Main article: Cetaceans in captivity

Further information: Beluga whale § Captivity

Some whales, like belugas, have been kept in special places called aquariums. These animals are often taken from the ocean, and living in tanks can be hard for them. Scientists also study whales to learn about their skills, like using sound to navigate. Keeping whales in captivity can help people learn, but it also makes us wonder about how well these smart animals are treated.