Whale (The Biggest Mammal On Earth)
Whales are large, magnificent, intelligent, aquatic mammals. They breathe air through their lungs (unlike fish who breathe through gills). Whales have sleek, streamlined bodies that move easily through the water. They are the only mammals, other than manatees (seacows), that live their entire lives in the water, and the only mammals that have adapted to life in the open oceans. Cetaceans are the group of mammals that includes the whales, dolphins, and porpoises
Like all mammals:
- Whales breathe air into their lungs.
- Whales have hair (although they have a lot less than land mammals, and have almost none as adults).
- Whales are warm-blooded (they maintain a high body temperature).
- Whales have mammary glands with which they nourish their young.
- Whales have a four-chambered heart.
SizeThe biggest whale is the blue whale, which grows to be about 29 metres long - the height of a 9-storey building. These enormous animals eat about four tons of tiny krill each day, obtained by filter feeding through baleen. Adult blue whales have no predators except man. The smallest whale is the dwarf sperm whale which as an adult is only 2.6 metres long. Swimming and other activitiesWhales have a streamlined shape and almost no hair as adults (it would cause drag while swimming). Killer whales and Shortfin Pilot whales are the fastest, swimming up to 30 miles per hour.Whales swim by moving their muscular tail (flukes) up and down. Fish swim by moving their tails left and right.Breaching
Many whales are very acrobatic. They even breach (jump) high out of the water and then slap the water as they come back down. Sometimes they twirl around while breaching. Breaching may be purely for play or may be used to loosen skin parasites. It might also carry some social meaning.
This is another cetacean activity in which the whale pokes its head out of the water and turns around, perhaps to take a look around.
Some whales stick their tail out of the water into the air, swing it around, and then slap it on the water's surface; this is called lobtailing. It makes a very loud sound. The meaning or purpose of lobtailing is unknown, but some believe that it's done to warn the pod of some kind of danger.
Logging is when a whale lies still on the surface of the water, resting, with its tail hanging down. While floating motionless, part of the head, the dorsal fin or parts of the back are exposed at the surface
Many ceteaceans, especially baleen whales, migrate over very long distances each year. They travel, sometimes in groups (pods), from cold-water feeding grounds to warm-water breeding grounds.
Gray whales make the longest seasonal migration. They travel about 12,500 miles each year.
Cetaceans have very strong social ties. The strongest social ties are between mother and calf. A social group of whales is called a pod. Baleen whales travel alone or in small pods. The toothed whales travel in large, sometimes stable pods. The toothed whales frequently hunt their prey in groups, migrate together, and share the care of their young.
Cetaceans give birth to live young who are nourished with milk from their mothers - they don't lay eggs. Cetaceans breed seasonally, usually in warm tropical waters, and females usually have one calf every 1-3 years. Whale calves can swim at or soon after birth. Mother whales care for their young for an extended period of time, usually for at least a year.
Young cetaceans are frequently mottled in colour, camouflaging them from predators. Newborns have a sparse covering of hair which they lose as adults
Complex whale songs can be heard for miles under the water. The humpback's song can last for 30 minutes. Baleen whales sing low-frequency songs; toothed whales emit whistles and clicks that they use for echolocation The songs are thought to be used to attract mates, to keep track of offspring, and for the toothed whales, to locate prey.
There are many species of whales that are in danger of becoming extinct. Most baleen whales (the huge whales targeted by commercial whalers) are listed as endangered or protected species. Most other whale species are doing well and are not endangered.