The blue whale is undoubtedly the largest animal that lives on Earth today. Their gigantic yet slender, narrow bodies swim gracefully along the ocean and occasionally swim towards the water surface to breathe air. Even though blue whales live in the ocean, they are not fish. Instead, they are mammals, and like dolphins, they breathe air into their lungs. They use a hole at the top of their head called a blowhole, which works like human nostrils do. But perhaps the most interesting thing about blue whales is their choice of food that contrasts greatly with their body size. It is ironically surprising that they prefer to eat the ocean’s tiniest animals for such a massive creature. But why? The answer lies in the structure of a blue whale’s teeth.
Do Blue Whales Have Teeth?
Believe it or not, blue whales don’t have actual teeth. Instead, they have hundreds of baleen plates hanging down from the roof of their upper mandible, where most fish teeth are located. These baleen look like giant bristles of comb, and they work like a sieve to filter millions of liters of water to eat tons of microscopic food. The blue whale is an interesting animal on its own, being the largest mammal, whether on land or at sea, and even surpassing giant dinosaurs’ size back in the day. Blue whales can grow beyond 100 feet, the size of three school buses end to end, and weighing more than 100 tons, which is equivalent to over nine school buses filled with children. However, despite their enormous size, blue whales are not terrifying carnivores. Instead, they eat microscopic animals such as krill, the world’s tiniest crustaceans, and copepods and catch them using a very reliable filter of baleen plates or whalebone. The baleen plates grow out perpendicular to the upper jaw, lining down as slats around the blue whale’s mouth opening. Each of the baleen plates forms a triangular shape. The blue whale’s baleen plates have tubules that split to generate a ragged edge on the tongue side and are equipped with densely packed strands at the bottom. Each strand of keratin-made baleen measures 2 millimeters or less in diameter.
What is a Baleen?
Baleen is composed of strong bristles packed between two rigid plates and appears in the blue whale’s mouth like vertical blinds across the top mandible. About 14 species of whales, including the blue whale, have baleen plates instead of teeth. They use these bristle-like plates as a giant sieve to filter krill, their favorite food, from the ocean. Baleen plates grow from the upper mandible of an adult blue whale and can extend to one meter long. These plates are made of keratin, the same protein that makes up human fingernails, and just like fingernails, they continuously grow and wear as well. The hard plates on the baleen that face the inside of the blue whale’s mouth wear much quicker than the bristles, causing them to stick out and intertwine. This entanglement forms a filter that aids the water to flow more easily but helps trap whichever prey is caught inside. So it is easy to get inside a blue whale’s mouth but harder to escape. Whales, dolphins, and porpoises are all classified under the order Cetacea. The term cetacean is derived from the Greek language meaning “sea monster.” The order Cetacea is classified into two sub-groups: the odontocetes (those with teeth), and mysticetes (whales with baleen).
How Many Baleen Plates Do Blue Whales Have?
Blue whales typically have around 350 baleen plates hanging down from each side of their top mandible. Out of around 90 species of cetaceans, 14 of them have baleen plates in replacement of teeth.
What Do Blue Whales Use Their Baleen For?
Generally, blue whales use their baleen plates to filter water with masses of krill and other zooplankton and trap them inside to eat as water flows back out. The blue whale partially seals its mouth after sucking in krill and water simultaneously, forcing the water to pass through the baleen as it returns to the ocean. The baleen bristles of blue whales can catch krill and other zooplankton as small as half a millimeter in size. Blue whales escalate their swimming speed when approaching a mass of krill to about 6.7 miles per hour. However, opening their massive mouths slows them down significantly as they need to exert great effort when opening them. This is why blue whales only eat when there are huge masses of krill on their way. Blue whales are observed to eat about 4 tons of krill in a single day.
Did Blue Whales Used to Have Teeth?
Scientists’ studies show the possibility of blue whales having teeth once upon a time. Like their land predecessors, the early blue whales are thought to have teeth. Some whales started suction eating by sucking in their prey with their tongues, which helped them evolve through time. The absence of teeth is said to have resulted in the development of baleen on the jaw, which enabled whales to sift their prey. Even though baleen whales do not grow teeth, tooth buds can still be seen in their embryonic stages.
