Whales: The biggest sea mammal
Whales are large, magnificent, intelligent, mammals that live in water. They belong to a group of mammals called Cetaceans. These include whales, dolphins, and porpoises.
Whales are not fish but are mammals because like all mammals, they breathe air into lungs, have hair, are warm-blooded, have mammary glands with which they nourish their young and have a four-chambered heart.
They are the only mammals, other than manatees (sea cows) that live their entire lives in the water. Unlike fish which breathe using gills, whales breathe air through blowholes into their lungs.
The blue whale is the largest animal that has ever existed on Earth. It is larger than any dinosaurs that existed. They are also the loudest animal on Earth.
They can grow to about 29 metres long - the height of a 9-story building. These enormous animals eat about 4 tons of tiny krill (sea food) each day. Adult whales have no predators except man.
The smallest whale is the dwarf sperm whale which as an adult is only 2.6 metres long.
Whales have a streamlined shape and as adults they lose their hair to prevent drag while swimming. Whales swim by moving their muscular tail (flukes) up and down instead of left and right like fish.
Whales have the strongest social ties which are formed between mother and calf. A social group of whales is called a pod. Whales travel in large pods, frequently hunt their prey in groups, migrate together, and share care of their young.
They give birth to live young who are nourished with milk from their mothers - they don’t lay eggs. This is usually in warm tropical waters and females usually have one calf every one to three years. Whale calves can swim at or soon after birth. Mother whales care for their young for at least a year by feeding them milk and protecting them.
One interesting thing about whales is that they sing songs. Whale’s songs can be heard for miles under the water. The songs can last for 30 minutes and are thought to be used in attracting mates, to keep track of offspring, and to locate prey.