In addition to being the largest member of the mammal family, the blue whale is also the largest creature known to have ever inhabited the planet. This marine giant grows up to 105 feet in length, can weigh up to 200 tons and can live to be 90 years old.
Even though the blue whale is the largest existing carnivorous creature, its diet mainly consists of tiny krill. Some scientists estimate that during the summer months a blue whale may consume 40 million krill a day, which amounts to about 7,900 pounds of food a day. The blue whale eats the tiny creatures by taking in large amounts of water containing krill and then letting the water back out through the baleen plates. The krill remain behind and the whale digests them.
Blue whales reproduce at a rate of about one calf every two or three years. Even at the birth, the calves are already large, measuring about 23 feet long and weighing about 5,000 pounds.
Blue whales inhabit oceans across the globe, but they are threatened by loss of habitat, toxins released into the water and other man-made causes. Conservation organizations, such as the World Wildlife Fund, are working towards ensuring the future survival of the blue whale.