Blue Whales 101 | Nat Geo Wild

Blue whales are the largest animals to have ever existed. As long as about three school buses and as heavy as 15, blue whales even outsize the dinosaurs. The whales' marine habitat contributes to their exceptional size. The ocean provides more room to grow and eliminates one of the factors that usually hinder animal size, gravity. Gravity limits the size of land animals to what their skeletons can support. The ocean's buoyancy spares marine mammals of this limitation, thereby allowing them to grow unlike any other animal. Blue whales have one of the loudest calls in the animal kingdom. Measuring up to 188 decibels, their song can be loud enough to overpower the sounds of jackhammers and jet engines. The whales use their powerful songs to communicate with each other, oftentimes from long distances. These vocalizations, which are deep moans and rhythmic low-frequency pulses, have been recorded from over 500 miles away. A blue whale's age can be determined by its earwax. About every six months, a new layer of earwax forms inside a whale's ear canal. The wax primarily serves to protect the ear canal and helps carry sound waves into the whale's inner ear. However, this buildup of wax layers, called an earplug, can be measured and used to estimate a whale's age, much like counting the rings in a tree trunk. The average lifespan of a blue whale is about 80 to 90 years, but the oldest one found, based on its waxy earplug count, was about 110 years old. Blue whales can eat four tons of food a day. That's more than an African elephant weighs. Despite the whale's enormous size, their diet primarily consists of tiny crustaceans called krill. The whales use their pouch-like lower jaws to scoop up swarms of thousands of krill floating in the water. The whales then push the water out of their mouths and through baleen bristles lining their upper jaws. The bristles are thin enough to let water through, but thick enough to catch krill. Whale baleen was often used in 19th-century fashion. Inaccurately referred to as whale bone, whale baleen is instead made of keratin, the same strong, flexible material found in fingernails. Keratin allowed baleen to become an ideal material for structuring clothes, such as corsets, collars, hat brims, and hooped frames in skirts. Because of the high commercial value of baleen and other whale body parts, blue whales were nearly exterminated. Today, thankfully, global bans on whaling were put in place, allowing the species to slowly rebound.