Fascinating Sperm Whale Information
Sperm whales are the largest toothed whales, with adult males measuring up to 20 metres. They are easily recognized by their massive heads and prominent rounded foreheads and are highly acoustic animals that emit powerful, regular clicks almost continuously while they are underwater.
They are believed to have diverged from other toothed whales early in the evolution of the suborder around 20 million years ago, and a number of fossil genera and species have been described from the Late Oligocene period and beyond.
Sperm whales are a prime example of a species that has been K-selected, a reproductive strategy associated with very stable environmental conditions that is characterized by a low birth rate, significant parental aid to offspring, slow maturation and high longevity. They are among the most sexually dimorphic (that is, males and females differ greatly) of all cetaceans.
They are easily the largest toothed carnivores on earth and are known to dive as deep as 3,280 feet (1,000 meters) in search of squid to eat. They are usually considered squid feeders but there are a few notes about small deep sea sharks' presence in their diet. They are among the most aggressive of whales; they battle 30-ft (9-m) giant squid to the death and have been known, when attacked, to sink a rowboat full of whalers. They are no match for modern whaling equipment, however.
Battles between Sperm Whales and colossal squid (which have been measured to weigh nearly 500 kg) have never been observed by humans, however white scars on the bodies of Sperm Whales are believed to be caused by squid. They are prodigious feeders and eat around 3% of their body weight per day.
They are known to dive deeper and for longer than any other animal and may stay submerged from 20 minutes to over an hour. They are not the easiest of whales to watch, due to their long dive times and ability to travel long distances underwater, although they are often seen logging and are relatively easy to approach in this state.
They are unique in that there seems to be nothing in the world's oceans that looks like a sperm whale. They are found in all oceans and latitudes from the equator to the edge of the polar pack ice (males only in the polar regions). They are usually found in deep off-shore waters, but may be seen closer to shore in areas where the continental shelf is small.
They are thought to live for 75 years or more and are mostly dark gray, but oftentimes the interior of the mouth is bright white, and some whales have white patches on the belly. They are highly gregarious, polygamous and group themselves roughly by age and sex in group sizes of 100 or more individuals.
While they are well adapted to diving, repeated dives to great depths do have long term effects on the whales. This damage may indicate that Sperm Whales are susceptible to decompression sickness, and it's possible that sudden surfacing could be lethal to them.
Sperm whales are considered an endangered species although they are still being targeted in a few areas: there is a small catch by primitive methods in Lamalera, Indonesia, and Japan takes sperm whales for scientific purposes. They are now common whale-watching attractions, especially in the waters around New Zealand.
Kevin conducts Party Wall Surveys, and deals with Party Wall Agreements. In his spare time he enjoys scuba and freediving.
