The telltale spouts that are formed on the surface occur when whales expel warm air that meets colder air on the surface and condenses into small water droplets. Breathingīoth baleen and toothed whales breathe through blowholes-the whale’s version of nostrils. The result is a capacity for complex behaviors and societies, especially in oceanic dolphins, including orcas. The brain to body size ratio is also important, and the only animals with a brain to body size ratio larger than whales are humans. In addition to large bodies, cetaceans have large brains- sperm whales currently hold the title for the largest absolute brain size on the planet. Their blood vessels are also able to constrict when an animal is in cold water, reducing the amount of energy needed to pump blood throughout the circulatory system and conserving heat. This exchange allows for cold blood in the limbs to move from the animal’s extremities in veins directly along arteries carrying warm blood from the animal’s core, instead of losing heat at the surface of the animal’s skin. Smaller species make use of higher metabolism and a counter-current heat exchange system of blood vessels in their flukes and flippers to keep warm. Larger species also retain heat because their skin surface area is small compared to the size of their bodies. The thicker blubber doesn’t necessarily mean that an animal is more insulated from the cold though-its main purpose is providing the animal with nutrition stores through winter months when food is scarce. Blubber thickness has quite the range-varying from two to more than 12 inches thick depending on the species. Blubber is also less dense than the seawater cetaceans swim in, similar to wetsuits used for surfing or diving, which gives the animals buoyancy and helps them float. Blubber is much thicker than the fat found in other mammals. Whales are able to survive in deep or freezing polar water because of a layer of fat, called blubber, covering their entire body underneath the skin. When present, the dorsal fin is helpful for stability and has no support in the way of bones. Their flippers (or pectoral fins) are modified forelimbs with an immobile elbow joint and are used mainly for steering, whereas flukes help propel the animals forward. Cetacean flukes move vertically through the water (unlike fish that typically move their tails horizontally back and forth). Whales may be large, but their bodies are streamlined to help aid in efficient swimming. (New England Aquarium, photographer Tim Frasier) The fluke from the right whale named Phoenix, as seen in 2004. Despite the popularity of whale watches and long-term interest in protecting whales, even knowing something as basic as the number of whales over time is a challenging question to answer. Their long migration routes and deep dives mean that they are not easy to track. We know that cetaceans are intelligent, but there is still so much to learn about how they think and communicate. We even sent humpback whale songs into outer space with the spacecrafts Voyager 1 and 2, engraved on golden records for another civilization to decipher. Whales have always captured our hearts-the moans that come from humpback whales and the clicks from common dolphins remind us of our own human conversations. On this page, we will generally refer to all cetaceans as whales, and in some instances specify when referring to traits or behaviors unique to toothed whales, baleen whales, or specific species. Despite their very different diets and sizes, both baleen whales (Mysticeti) and toothed whales (Odontoceti) share a common (and perhaps surprising) ancestor-land-dwelling mammals related to today’s hippos that lived over 50 million years ago. They are found in all of the world’s oceans, and even in some freshwater rivers. But cetaceans also include dolphins, porpoises and other toothed whales, and in total contain more than 80 different species. When we think of whales, the enormous ones that filter tiny plankton from seawater with their baleen-fringed upper jaw often come first to mind (like the right whale in the picture above).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |