Size Matters: The Blue Whale

At over 10 feet tall and weighing more than five tons, the African bush elephant is largest land mammal alive today. These behemoths seem like mere insects compared to some of the great dinosaurs; the largest sauropods could weigh as much as an entire herd of elephants! Despite this immensity, there are still even bigger beasts. In order to achieve truly tremendous size, it helps to live in the gravity-free environment of the ocean. Of all marine megafauna there is one titan that eclipses all other animals, past and present, in terms of sheer scale. Prepare to meet the largest animal that has ever existed in the history of planet Earth, the blue whale.

How big is a blue whale?

Not only is the blue whale the largest of the great whales, it is the largest animal ever. They grow to lengths of more than 100 feet from snout to flukes and it is believed they can reach weights of 200 tons. That is about as heavy as 40 elephants, and substantially more than double the weight of the largest dinosaur. Calves are about 23 feet long and three tons at birth and while nursing can put on more than 200 pounds a day. Despite its size, the blue whale is relative slender in built and is capable of greet speed. While they usually cruise at around 12 miles an hour, the have been documented traveling and over 30 miles per hour in bursts. Its heart alone weighs over 400 pounds and is the largest of any animal.

Where do blue whales live?

Blue whales can be found throughout the oceans of the world. They are known to migrate vast distances between their breeding and feeding grounds. Populations can be found in the northern waters of both the Pacific and Atlantic oceans as well as in the Indian Ocean and Antarctic. They prefer to swim at depths of between 40 and 50 feet, although than can dive as deep as 1600 feet.

What do blue whales eat?

While whales are often thought of as gentle giants, they are in fact predators. Blue whales hunt some of the smallest creatures in the ocean, a type of crustacean known as krill. Rather than preying on individuals, they utilize a form of filter feeding known as lunge-feeding to swallow entire shoals at once. Thanks to its expandable throat and loosely connected jaws, a blue whale and open its mouth wide wide to engulf nearly its body weight in seawater in one go as they swim through a krill swarm. As it closes its jaws, it uses its tongue to force water out through the baleen plates that hang from the upper gums to trap krill. These plates can measure more than three feet long and are made of keratin, the same material that makes hair, hooves, claws, and horns. Despite having such a cavernous maw, a blue whale cannot swallow anything much bigger than a beach ball without risk of choking. A blue whale can eat nearly four tons of krill in a single day. This form of feeding can be indiscriminate and the whales wind up accidentally swallowing small fish, squid, and other crustaceans. When feeding, the whales dive to depths of 330 feet for 10 to 20 minutes at a time.

Do blue whales have any predators?

Thanks to its size, an adult blue whale is virtually immune to predation. While many whales bear scars from orca attacks, even a pod of orca cannot bring down prey as large and strong as a blue whale. However, this species was heavily harvested during the whaling days and nearly hunted to extinction. While their numbers have rebounded to a global population of an estimated 25,000 individuals, blue whales are endangered. One of their biggest threats comes from the risk of being hit by ships. They are also vulnerable to oceanic noise pollution, which drowns out their calls, and being entangled in fishing gear. As with all marine life blue whales are threatened by climate change, which may alter their migration routes and food supply.