LOUDNESS
Blue whales are the loudest animals on Earth! Their call reaches levels up to 188 decibels. This low-frequency whistle can be heard for hundreds of miles. The blue whale is louder than a jet, which reaches only 140 decibels! Human shouting is 70 decibels; sounds over 120 decibels are painful to human ears.
SKIN, SHAPE AND FINS
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; they are sometimes called "sulfur bottom."
They have a very small, falcate (sickle-shaped) dorsal fin that is located near the flukes (tail). Blue whales have long, thin flippers 8 feet long (2.4 m) and flukes that are 25 feet (7.6 m) wide.
DIET AND BALEEN
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. They are gulpers, filter feeders that alternatively swim then gulp a mouthful of plankton or fish - they lunge into dense groups of small sea organisms (krill or tiny fish) with an open mouth. 50 to 70 throat pleats allow the throat to expand a great deal, forming a gular pouch. The water is then forced through the baleen plates hanging from the upper jaw. The baleen catches the food, acting like a sieve.
The blue whale has about 320 pairs of black baleen plates with dark gray bristles in the blue whale's jaws. They are about 39 inches long (1 m), 21 inches wide (53 cm), and weigh 200 pounds (90 kg). The tongue weighs 4 tons (3.8 tonnes).
An average-sized blue whale will eat 2,000-9,000 pounds (900-4100 kg) of plankton each day during the summer feeding season in cold, arctic waters ( about 120 days).
SOCIAL GROUPS
Blue whales live individually or in very small pods (groups). They frequently swim in pairs.
DIVING
Blue whales can dive for up to an hour, going to a depth of 350 feet (105 m).
SPOUTING - BREATHING
Blue whales breathe air at the surface of the water through 2 blowholes located near the top of the head. They spout (breathe) about 1-4 times per minute at rest, and 5-12 times per minutes after a deep dive. Their blow is a single stream that rises 40-50 feet (12-15 m) above the surface of the water.
SPEED
Blue whales are very fast swimmers; they normally swim 3-20 mph (4.8-32 kph), but can go up to 24-30 mph (38-48 kph) in bursts when in danger. Feeding speeds are slower, about 1-4 mph (1.6-6.2 kph).
VOCALIZATION
Blue whales emit very loud, highly structured, repetitive low-frequency sounds that can travel for many miles underwater. They are probably the loudest animals alive, louder than a jet engine. These songs may be used for locating large masses of krill (tiny crustaceans that they eat) and for communicating with other blue whales, especially in order to attract and find mates
HABITAT AND RANGE
Blue whales live at the surface of the ocean and are found in all the oceans of the world.