Species Profile: The Sperm Whale

Learn all about the sperm whale: a very unique and popular whale indeed. 

Mother Sperm Whale With Calf

Mother Sperm Whale With Calf Off Mauritius. (Author: Gabriel Barathieu/Wiki Commons cc by-s.a. 2.0)

The Sperm whale is one of the biggest whales on earth.

It’s the largest of the toothed whales and is also the largest toothed predator on Earth. It is the only living member of the genus Physeter. This whale is also one of the three species of the Sperm whale family together with the Dwarf Sperm Whale and the Pygmy Sperm Whale both of the genus Kogia.

Sperm whales have a worldwide range and they are also migratory: they migrate seasonally for breeding and feeding.

These are large whales that often grow up to 20.5 meters (67 feet) long. They have a distinct block-shaped head that takes up to one-third of the animal’s total body length. That’s because it holds the title of the animal with the largest brain on Earth: more than five times the weight of a human brain.

They are prominent users of echolocation and communication and they can vocalize at up to 230 decibels underwater.

Sperm whales are one of the most hunted whales of all time!

Almost every part of their body was highly sought after by the whaling industry: spermaceti for oil lamps, lubricants, and candles. Ambergris (from its digestive tract) as a fixative in perfumes. Even after death its body is still valuable as ambergris remains as flotsam from deceased whales and is quickly scooped up by beachcombers.

Interestingly, a whale of this species was the inspiration behind the 1851 classic tale Moby Dick by Herman Melville. Apparently, the vengeful fictional whale was actually inspired by the activities of a real-life sperm whale.

This whale attacked and sunk the Nantucket whaling boat Essex in the southern Pacific Ocean in November 1820. You can read more about the horrific events that followed the sinking of the Essex as told by some of the survivors by clicking here.

The sperm whale is now protected by a whaling moratorium, and it’s listed as Vulnerable by the International Union for the Conservation of Nature  (IUCN).

 The sperm whale is a very deep diver: going down to 2,250 meters (7,382 feet) and it’s the second deepest diving mammal. Only the Cuvier’s beaked whale dives deeper than it.

1) Scientific Name

Physeter Macrocephalus

2) Scientific Classification:

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Cetacea
  • Family: Physeteridae
  • Genus: Physeter
  • Species: Macrocephalus

3) Life Expectancy

Sperm whales may live for up to 50 – 70 years.

4) Average/Maximum Length

An adult male sperm whale is typically larger than a female. The former can reach an average length of 16 meters (52 feet) and a maximum of up to 20 meters (65.6 feet).  Females reach an average length of 10.7 meters (35 feet) and a maximum length of 13.1 meters (43 feet).

5) Average/Maximum Weight

With females weighing less than the males, the average weight of a sperm whale can be anything around 12.2 tons and a maximum of 45 tons for the largest adult males.

 Sperm whales are among the most sexually dimorphic of all cetaceans. Though both sexes measure about the same at birth, adult males are up to 30/50 percent longer than female and about three times more massive.

6) Maximum Swimming Speed

Measuring the swimming speeds of Sperm whales is difficult mostly because they are very deep divers.

However, research shows the average speed of these whales is about 3 – 9 mph (4.8 – 14.4 km/h) at the surface. Though they can quickly reach up 21 to 27 mph (34 to 43 km/h) and maintain that speed up to an hour when they are fleeing from danger.

7) Interaction With/Danger To Humans

  • Interaction with humans

Historically, the interaction between humans and sperm whales has been a disastrous one and the whale was nearly rendered extinct by whaling expeditions between the 18th century and 20th century.

In fact, this was one of the most highly sought after whale by commercial whalers.

Whalers hunted the sperm whale as a result of demand for the spermaceti from its head, whale oil from the blubber, Ambergris from the whale’s gut, their teeth for ornaments, and for their meat (which is said to taste better than chicken!).

These substances were used for ornamental and commercial purposes such as perfume production, automotive lubrication, candle making, and production of carvings.

To date, sperm whales still suffer negatively from human interactions despite the ban on whaling. This is mostly due to getting entangled by fishing nets either deliberately or unconsciously. They also suffer the adverse effects of ocean pollution such as swallowing man-made objects and chemical pollution.

  • Danger to humans

Sperm whales in modern times pose no danger to humans but there are many cases in history of adult sperm whales (bulls), using their heads to ram and sink whaling boats in an attempt to escape capture.

This led to the death of many sailors.

There is no known natural predator of the sperm whale probably due to its sheer size and aggressiveness. However, orca whales have been known to attack and overwhelm sperm whale calves and weak individuals. Such hunting tactics are successful because orcas tend to hunt in groups.

8) Reproduction Details

Male sperm whales normally live alone or in small groups in the case of old whales or immature males while females live in packs called pods which consist of about 10 – 40 females and their juveniles.

Mating seasons starts in mid-summer around the month of April. Males fight each other during mating by butting and biting. They may also be assisted by females who help them chase away old males.

A single male mates with multiple females resulting in the birth of 3.7 to 4 meters (12 to 13 feet) calves born after a gestation period of 14 to 16 months. The lactation period then proceeds for 19 to 42 months and calves are allowed to suckle from other females other than their own mothers.

Males do not provide any care at all to their calves.

A sperm whale’s milk has a high-fat content (about 36 percent), a quality that prevents it dissolving in water before the calf can eat it. The energy content contained in the milk is also much higher than in other mammals and is about 3,840 kcal/kg.

Females do not reach sexual maturity till they attain 9 years while males, on the other hand, attain maturity on their 18th birthday.

9) Diet/Hunting Pattern Of The Sperm Whale

These whales are voracious feeders and can take in as much as 3 percent of their body weight. This great appetite calls for great skill in their hunting expeditions; a task they accomplish with dexterity.

The sperm whale’s diet consists mainly of giant and medium sized squid, small sharks, rays, octopuses and shrimp, while other food items may be caught in the process of hunting.

They can dive as deep as 3 kilometers and stay under water for up to 2 hours in search of prey.

They primarily use echolocation to hunt and female whales are known to hunt in groups. Hunting is not an easy affair for sperm whales and they often sustain injuries from battles with colossal squids which resist capture.

10) Alternative Names

  • Cachalot

11) Population And Conservation Status

The worldwide population of sperm whales is unknown but estimates put it at hundreds of thousands.

Exact populations in the north Pacific are at 40,000 – 80,000, while populations in the southern hemisphere are about 32,000. Though commercial whaling of this species is banned, populations are still nothing like the pre-whaling era.

A combination of other factors such as ocean pollution and human disturbances makes the sperm whale an animal categorized as Vulnerable by the International Union for Conservation of Nature (IUCN).

12) Ancestry And History

The name sperm whale is a short form of spermaceti whale. Spermaceti, is the semi-liquid and waxy substance found within the whale’s head. This whale is also referred to as the “cachalot.”

Its scientific genus name Physeter comes from the Greek word physētēr meaning “blowpipe or blowhole of a whale.” Macrocephalus means “big-headed.” This whale has visible teeth only in its lower jaw hence the synonymous specific name catodon which means “down-tooth” derived from the Greek words cat (below) and odon (tooth).

The earliest fossils of the Sperm whale are known from 25 million years ago during the Oligocene period. Its ancestry traces back to the last 56 to 33.9 million years during the Eocene epoch before diverging from the line leading to the porpoises and dolphins.

13) Distribution And Habitat

Sperm whales are the most cosmopolitan of all whales and they live in all the oceans of the world particularly between 40 degrees north and 40 degrees south of the equator.

These whales seem to prefer deep offshore water but may also be spotted in shallow water around continental shelves. Male Sperm whales mainly spend most of their lives in colder ocean waters poleward where hunting is productive, but migrate to temperate oceans to mate. Females and juveniles, on the other hand, are mostly found in tropical and temperate waters.

Some popular locations for sperm whale watching are Kaikoura on New Zealand’s South Island, Andenes and Tromsø in Arctic Norway, the Azores, and close to the shores of Dominica.

 

References:

1. http://www.nationalgeographic.com/animals/mammals/s/sperm-whale/

2. https://en.wikipedia.org/wiki/Moby_Dick_(whale)

3. https://www.afsc.noaa.gov/nmml/education/cetaceans/sperm.php

4. https://en.wikipedia.org/wiki/Physeteroidea

5. https://www.afsc.noaa.gov/nmml/education/cetaceans/baleen1.php

Photo Credits:

https://en.wikipedia.org/wiki/Sperm_whale#/media/File:Mother_and_baby_sperm_whale.jpg

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