Blue Whale

The females are generally larger than the males, this is the case for all baleen whales. "The largest specimen found was a female 94 feet (29m) long weighing more than 174 tons" (Satchell 1998). The head of the Blue whale forms up to a quarter of the total body length. Compared with other rorquals, the head is very broad. The blue whale heart is the size of a small car and can pump almost 10 tons of blood throughout the body. They have a very small, falcate (sickle-shaped) dorsal fin that is located near the fluke, or tail. Blue whales have long, thin flippers 8 feet (2.4m) long and flukes that are 25feet (7.6m) wide. The blue whale's skin is usually blue-gray with white-gray spots. The underbelly has brown, yellow, or gray specks. During the winter, in cold waters, diatoms stick to the underbelly, giving it a yellow to silver- to sulfur-colored sheen; giving the blue whale its nick-name of "sulfur bottoms". Other names include Sibbald's Rorqual and Great Northern Rorqual. Blue whales (like all baleen whales) are seasonal feeders and carnivores that filter feed tiny crustaceans (krill, copepods, etc), plankton, and small fish from the water. Krill, or shrimp-like euphasiids are no longer than 3 inches. It is amazing that the world's largest animals feed on the smallest marine life. Blue whales are gulpers, filter feeders that alternatively swim then gulp a mouthful of plankton or fish. "An average-sized blue whale will eat 2,000-9,000 pounds (900-4100kg) of plankton each day during the summer feeding season in cold, arctic waters (120 days)" (Hasley 1984). The blue whale has twin blowholes with exceptionally large fleshy splashguards to the front and sides. It has about 320 pairs of black baleen plates with dark gray bristles in the blue whale's jaws. These plates can be 35-39 inches (90cm-1m) long, 21 inches (53cm) wide, and weigh 200 pounds (90kg). This is the largest of all the rorquals, but not the largest of all the whales.