Animal stories: Blue whales

Blue Whales are the largest and loudest marine mammals on Earth. They grow upto 80 feet long on average, weighing about 120 tonnes and are louder than a jet plane. Their heart is as large as a small car and nearly 50 people could stand on their tongue.

The skin is usually blue-grey with white-grey spots. The underbelly has brown, yellow, or gray specks. They have a very small, sickle-shaped dorsal fin that is located near the tail. Blue whales have long, thin flippers eight feet long and tails that are 25 feet wide.

There are about 10,000-14,000 blue whales worldwide. The female whales are larger than males. Blue whales breathe through two blowholes located near the top of the head. And when they breathe, their blow is a single stream that rises 40-50 feet above the surface of the water.

Hunting styles

Blue whales are gulpers, filter feeders that alternatively swim then gulp a mouthful of plankton or fish with an open mouth. They filter some six to seven tonnes of krill (small shrimp like animal) at a time with their baleen plates, gulping water and krill, then closing the mouth and forcing the water back out through the baleen. Blue whales have pleated throat grooves that allow their throat to expand during the huge intake of water during filter feeding.

Favourite food

Blue whales are carnivores and seasonal feeders. An average-sized blue whale will eat 900-4100 kg of plankton each day. They mainly feed on krill and small fish. During their feeding season, they consume more than 4-6 tonnes of krill in one day. Though being the world’s biggest mammal, they eat animals that are less than 1/1000th their size.

Their homes

Blue whales live at the surface of the ocean and are found in all the oceans of the world. They are not found in polar seas and are rarely seen near the coast. Blue whales are found worldwide. They frequently swim in pairs and live in small groups called pods.

Young ones

Blue whales are mammals rather than a fish. They are warm-blooded and have lungs rather than gills and nourish their young ones with milk. Their milk supposedly tastes like a mixture of fish, liver, milk of magnesia, and castor oil that is very rich and nourishing for baby whales. A baby blue whale drinks over 50 gallons of its mother’s milk in a day. In its first several weeks of life, it gains 10 pounds an hour. When a baby blue whale is about six months old, it starts to eat krill. The mother and baby may stay together for a year or longer. Blue whales reach maturity at 10-15 years. They have a life expectancy of 35-40 years.

Louder than a jet

Blue whales are the loudest animals alive. They produce very loud sounds that can be heard for hundreds of miles. Their call reaches levels up to 188 decibels whereas human shouting is only 70 decibels. Sounds over 120 decibels are painful to human ears. The blue whale is louder than a jet, which reaches only 140 decibels. Their loud sounds may be used specially to attract their mates. It is also used for locating large masses of krill and to communicate with other blue whales.