Common Dolphins and Baleens
Toothless and Baleen Whales (including bottlenose dolphins and porpoise) have unique teeth; however, the exact number, shape, size and function of their teeth differs from species to species, and even from individual species to individual years. Whales, which are carnivores, obtain their sharpened teeth through the method of biting down on a hard surface. Most have what is known as “dentition,” where the lower half of the tooth is ground down by powerful muscular action to aid in extracting food. Some, such as Orphan whales, use their teeth in a special way to grab fish and other forms of food; however, others only use the teeth for grabbing onto things such as their food.
The most famous species in the ocean, however, is the Great White Shark, also referred to as the largest fish in the world. Like all Great White sharks, it has a head nearly as long as its length, a broad, rounded trunk, and large, pointed teeth. Unlike most other species of sharks, however, these teeth do not bear any teeth marks, unlike the rows of ridges along each side of its mouth. These ridges, or “teeth banks,” allow a shark to grind its prey into gravel or sand, and ingest bits of meat stuck in between its teeth as they eat.
Only six types of baleen whales include the largest populations in the world. These include the Right Whale, Humpback, Short-finned Pilot Whale, the Long-finned Pilot Whale, the Minke Whale, and the Orca (sometimes called the Orca whale dog because it looks like a dog – in fact, its name was derived from a myth that a creature like this hunted the sailors with great dogs, hence the name). Baleen whales include both pelagic (water-bound) species and baleen whales which lie on the surface of the water, feeding on small crustaceans, small fish, and other marine mammals. While the latter have evolved into the herbivore genre, the former have evolved into carnivores. This means that baleen whales and their tusks have been key contributors to the ecosystem by helping to trap smaller prey animals and by eliminating larger predators.
Toothed whales and dolphins are land-based species, being distinguished from marine mammals by their jointed bodies. These members of the Testudines group have evolved into arms which end in the lower jaw. The paired fins of these species provide them with a means to propel themselves through the water, although they usually use their face and feet for this purpose. Dolphins are known to use both their face and feet for swimming. Although they resemble baleen whales in appearance, they have a total body length three times that of the latter.
Many marine biologists consider the leather-backed dolphin, the common dolphin, to be a subspecies of the bottlenose dolphin, which is most likely the same species as the common baleen whale. Whales, along with several other species of the genus Valla, have a very complex social structure, with pups forming pods, and the adults tending to be territorial. They also practice what is called “stranding” which involves moving together over long distances when the pod’s numbers dwindle. Strangers will sometimes join these pods, sometimes swimming with the calves while nursing, but this practice is not recommended, as it can cause stress to the calves. The mothers will nurse their own young until they are weaned by another of their offspring. In certain parts of the South Pacific, mothers feed their calves just once a day at most, but in other parts of the world they nurse their children up to twelve times each day.
The Balaen whale is the largest predatory dolphin among all species of cetaceans, with the exception of the blue whales. It has unique elongated jaws, which are as wide as its widest known shoulder. The Balaen’s prominent lower teeth, which project far into the water, help it snag fish and clamber along with groups of prey that have been strung across its powerful jaws. The Balaen’s name comes from the German words balaen, meaning “to bite” and ein, meaning “to swim”. Because of the baleen whale’s powerful bite force, it preys mostly on fish of prey and baleen whales are therefore known as the carnivores of the Pacific Ocean.