SPERM WHALE

GENERAL DESCRIPTION The sperm whale is a toothed whale that lives in pods. It has a huge brain that weighs about 20 pounds (9 kg); it is the largest brain of any animal. The sperm whale has a single blowhole that is s-shaped and about 20 inches long. The blowhole is located on the left side of the front if its huge head. The sperm whale has a 4-12 inch thick layer of blubber. Sperm whales produce ambergris, a dark, waxy substance (related to cholesterol) that is produced in the lower intestines, and is sometimes found containing squid beaks. Ambergris may help protect the sperm whale from the stings on the giant squid, its major food. Large lumps of ambergris may be vomited up by the sperm whale. The fictional Moby Dick was a sperm whale. SIZE Sperm whales are the largest toothed whales. Adult males grow to be about 50-60 feet (17-20 m) long, weighing about 40-50 tons (36-45 tonnes). Females are smaller, about 33-40 feet (11-13 m) long, weighing about 14-18 tons. The four-chambered heart of the average sperm whale weighs about 277 pounds (126 kg) - about as much as two average adult human beings. SKIN, SHAPE AND FINS The skin is usually dark gray to black, but is occasionally light gray. It has a distinctive, prune-like texture. Sperm whales have the largest head of any animal. It can be about 20 feet long (6 m), 10 feet high (3 m), and 7 feet (2.1 m) across, and is about one-third of the whale's body length. The head has a distinctive box-like shape. The heads are frequently covered with circular scars that are made by the suckers of the giant squid that they hunt and eat. It has 5-foot (1.5 m) long flippers that are about 3 feet (0.9 m) wide. There is no dorsal fin but there is a small hump two-thirds of the way down its back. There are also some ridges between the hump and the tail flukes. THE NAME The sperm whale was named for the valuable spermaceti oil (wax) that this whale produces in the spermaceti organ (located in its head). DIET, HUNTING, AND TEETH Sperm whales are carnivores that mostly eat giant squid that live on the ocean bottom at great depths. They also eat fish , octopus, and skate. In 1998, off the coast of Indonesia, 3 sperm whales were observed attacking a rare, filter feeding megamouth shark. An adult Sperm Whale can eat about a ton of food each day. Sperm whale teeth are uniform. The teeth in the upper jaw never erupt. The teeth in the long, thin lower jaw are conical and huge, about 7 inches (18 cm) long. These teeth weigh about 2 pounds (900 g) each. The lower jaw is about 16 feet (5 m) long and has about 50-60 teeth in it. When the whale's mouth is closed, the teeth fit into sockets in the upper jaw. SOCIAL GROUPS The bonds between the members of sperm whale pods are strong and long-lasting. The members of a pod protect the young, the sick and the injured. Groups of females with their young are common. This group structure allows a mother to dive very deeply to hunt while leaving her young calf, who is unable to dive very deeply, at the surface and protected by the pod. DIVING Sperm whales are the deepest diving whales. Although they live at the surface they dive to hunt giant squid that are bottom dwellers. They have been known to dive as deeply as 10,500 feet (3,200 m), but average dives are about 4,000 feet (1,200 m) deep. The Sperm whale can hold its breath for about an hour. SPOUTING-BREATHING Whales breathe air at the surface of the water through a single, s-shaped blowhole. The blowhole is located on the left side of the front if its huge head. They spout (breathe) 3-5 times per minute at rest, but the rate increases to 6-7 times per minute after a dive. The blow is a noisy, single stream that rises up to 50 feet (15 m) above the surface of the water and points forward and to the left of the whale at a 45° angle. LOGGING Logging is when a whale lies still at the surface of the water, resting, with its tail hanging down. While floating motionless, part of the head, the dorsal fin or parts of the back are exposed at the surface. Sperm whales are often seen logging and are relatively easy to approach in this state. LOBTAILING Sperm whales also stick their tail out of the water into the air, swing it around, and then slap it on the water's surface; this is called lobtailing. It makes a very loud sound. The meaning or purpose of lobtailing is unknown, but may be done as a warning to the rest of the pod or as some other type of communication. VOCALIZATION Sperm whales use echolocation to catch their prey in the dark oceanic depths. Mothers also use it it keep track of their young calf when they are diving to hunt; a calf cannot dive very deeply because it has to breathe much more frequently than the mother does. HABITAT Sperm whales are found in many open oceans, both in tropical and cool waters. Sperm whales live at the surface of the ocean but dive very deeply to catch the giant squid. SPEED The sperm whale swims leisurely at the surface at about 3-9 mph (4.8-14.4 kph). They can sustain a faster pace, when fleeing danger, of 21-27 mph (34-43 kph) for up to an hour. REPRODUCTION Sperm whale breeding is not very dependent on the seasons. The gestation period is over 16 months and the calf is born tail first near the surface of the water. The newborn instinctively swims to the surface within 10 seconds for its first breath; it is helped by its mother. Within 30 minutes of its birth the baby whale can swim. The newborn calf is about 13 feet (4 m) long and weighs about 1 ton (0.9 tonnes). Twins are extremely rare (about 1% of births); there is almost always one calf. The interval between births is about 3-4 years. A female reaches maturity at 9-10 years (males reach maturity at 18-19 years) and lives to be about 40 years old. On average, a female will give birth to about 7-10 calves. Frequently, other whales "assist" in the birth. The baby is nurtured with its mother's milk and is weaned in about 2 years. Calves drink 45 pounds (20 kg) of milk each day. LIFE SPAN Sperm whales have a life expectancy of over 70 years. POPULATION COUNT It is estimated that there are about 200,000 sperm whales world-wide. Sperm whales are considered an endangered species. These whales (and many other large whales) were over-hunted for many years, since their meat, oil, and other body parts are very valuable. Since whale hunting has decreased in the last few decades, their populations are starting to recover. CLASSIFICATION Sperm whales (Physeter macrocephalus) are toothed whales (Suborder Odontoceti) although DNA analysis shows that the Sperm whale is actually more closely related to the baleen whales. These whales are one of 76 cetacean species and are marine mammals.