Sperm Whale

Sperm Whale

  • Scientific name: Physeter macrocephalus
  • Also known as: Cachalot
  • Size: Typical fully grown males are 13 – 16 metres, but have been confirmed as growing to over 20 metres and 40 tons. Females are generally two-thirds to three-quarters of the size of males.
  • IUCN Status
    • Global: VU (Vulnerable)
    • Europe: VU (Vulnerable)
  • Distribution: Widespread but dispersed population across deep, open water of all of the world’s seas and oceans.
  • Feeds on: Mostly large, deep-sea squid, although fish species will also be eaten as well.
  • Description: Extremely large whale species which has a large square head (which makes up around one-third of the overall body length) with relatively narrow, long jaws. Teeth are only present in the lower jaw. The body is long and cylindrical with large flat tail flukes. The blowhole is unusually offset to the left. Colour is usually dark greyish.

Sperm whales are a very large whale species and the largest toothed predator in the world. Sperm whales are intelligent animals which show high levels of social behaviour. While sperm whales were previously commercially exploited by humans and are classed as Vulnerable by the IUCN (International Union for the Conservation of Nature) there is now international protection for this species.


Sperm whales are found in deep water in all of the major seas and oceans of the world. They are usually found far away from land in the open ocean in water which is several thousand metres deep. While sperm whales are not common in British watesr they are sighted from time to time. In 2013 a pod of fourteen sperm whales were sighted in the Firth of Fourth just a mile away from land, and a number of sperm whales washed up on the coastline of England and other European countries in 2016 (see below).

Life Cycle

Sperm Whale Size Comparison
Size comparison between fully grown male and female sperm whales and a human.

Sperm whales are thought to live for around seventy years. They display high levels of social cohesiveness with females looking after their young for many years after birth (there is also evidence that females teach their young how to hunt) and members of the group protecting weaker or injured individuals. Fully grown males are usually solitary creatures which gather with other sperm whales only to breed. Sperm whales are thought to communicate using clicking noises known as codas, although this is poorly understood.


Squid Battle
A display depicting a battle between a giant squid and a sperm whale at the Museum of Natural History in New York City.

Sperm whales feed primarily on large squid species. They can reach maximum depths of several thousand metres and spend two hours underwater hunting their prey. It is believed that sperm whales will regularly eat squid which are in excess of 30lb in weight, and very large sperm whales will often take on squid which are much larger than this. Indeed, sperm whales have been found with wounds on their heads caused by the lashing tentacles of colossal and giant squid. It is believed that the giant squid have evolved the largest eyes in the animal kingdom – they are more than 30cm across – so that they can spot approaching sperm whales, while sperm whales have retractable eyes, which possibly evolved as a defence against the tentacles of the squid. While squid is the main source of food for sperm whales they are also thought to feed on fish and the smaller shark species from time to time if squid are not present. See a computer generated video of a large sperm whale battling with a giant squid on YouTube here.

A skeleton of a sperm whale in the National Museum of Scotland in Edinburgh. Teeth are only present in the lower jaw and fit into holes in the upper jaw.

The teeth of the sperm whale are something of a mystery to science. Arround 20 – 28 pairs of large teeth are present on the lower jaw and fit into holes in the upper jaw. However, the teeth do not begin to grow until the sperm whale is already well-developed and young sperm whales without teeth, as well as those with damaged or deformed lower jaws, appear to be able to hunt and feed as well as those with teeth.

European Sperm Whale Strandings

Sperm whales have become beached in various locations around the British Isles in recent years – in 2011 a 13.5 metre, 20 ton sperm whales was found dead on Redcar beach, North Yorkshire and in early 2014 a large sperm whale washed up dead on a beach near Edinburgh. In early 2016 a 14 metre sperm whale washed up on a beach in Hunstanton in Norfolk and was followed by three more large sperm whales washing up on a beach in Lincolnshire. Finally, a fifth sperm whale washed up on another Lincolnshire beach a short time later. All of the sperm whales were believed to come from the same pod which had entered the North Sea at the start of the year, with the rest of the whales also dying and washing up on beaches in Germany and the Netherlands.

Sperm Whale Beached
A sperm whale beached on a Norfolk beach in 2006. In the first few months of 2016 twenty-nine sperm whales washed up in European countries.

Sperm whales are adapted to live and feed in deep water and rely on their echolocation and biosonar to find navigate. In the relatively shallow North Sea which also has a sandy and muddy seabed their echolocation does not work as well and they soon become disoriented and lost, often finding themselves in shallow water and ending up beached. Once they are stranded their is little hope for sperm whales as they soon overheat and their bodies cannot support the internal organs once the whale is outside of the water, leading to organ failure. On 4th February another large sperm whale washed up on the beach at Hunstanton, bringing the number stranded on beaches in Europe in 2016 to twenty-nine.

In May 2016 the Sunday Times reported that pollution may have played a role in the sperm whale beachings. They claimed that PCBs used in flame retardants, pesticides, sealants, adhesives and a range of other applications until the 1970s have contaminated the sea and had a major effect on sperm whales. The newspaper stated that PCBs suppress the immune systems of the whales, leaving them vulnerable to bacterial and parasitic infections, meaning they no longer have the strength to prevent themselves from becoming beached. It was also claimed that PCBs reduced the fertility of female sperm whales by up to fifty per cent.

In September 2017 a new theory emerged when research published in the International Journal of Astrobiology suggested that the sperm whale strandings may have been caused by the natural phenomena known as the northern lights. Officially called Aurora Borealis, the northern lights are spectacular displays of green, red, pink, purple and yellow dancing lights which appear in the night sky, caused by charged particles from the sun reacting with earth’s atmosphere.

Northern lights
Aurora Borealis – the northern lights – may be the cause of the sperm whale strandings.

Sperm whales are believed to navigate using the earth’s magnetic fields, which are disrupted and distorted by the northern lights. As the European sperm whale strandings happened during a particularly large display of the northern lights scientists now think that the two incidents are linked, and the whales may have been thrown off course by the disruption to the earth’s magnetic fields and ended up trapped in the shallow areas of the North Sea, ending up becoming beached.

In December 2020 the worst sperm whale stranding in England since records began in 2013 took place. Ten juvenile sperm whales were found stranded on a beach on the coast of East Yorkshire on Christmas Eve. The British Divers Marine Life Rescue were sent to the area but said that they were not able to lead the whales back out to sea due to the rough conditions. It is believed that the sperm whales may have become disoriented in the shallow water leading to them becoming beached.


Sperm whales are so-called because of the spermaceti organ which is located in the whale’s head. In a fully mature sperm whale this organ contains a mix of hundreds of litres of wax and oil and it is thought that the sperm whale can heat or cool this to help with diving. The purpose of this organ is poorly understood and some scientists believe it could be used in echolocation, but whalers who caught sperm whales in previous centuries believed this liquid was semen, hence the name of this species of whale.

Hunting of Sperm Whales

Sperm Whale Hunting 1850s
Picture depicting a sperm whale hunt in the 1860s.

Sperm whales were hunted across the world by sailboats from the 1700s. While the meat of this species was sometimes sold the main value was in the spermaceti. This had a wide range of uses including being refined into sperm oil which could then be used as a bright burning and odour free lamp oil and also used as an industrial lubricant. Indeed, sperm oil was widely used as a lubricant in the gearboxes of many US cars until the 1970s – once sperm oil was banned as a lubricant in gearboxes there was a big increase the gearbox failures in American cars in the mid to late 1970s. Sperm whales also produce the extremely valuable substance ambergris (see below), which is unique to this species.

Sperm Oil
Sperm oil is derived from spermaceti from sperm whales.

Hunting sperm whales in these days was extremely dangerous as a large boat would lower down smaller boats which would then harpoon a sperm whale and allow it to drag them through the sea until it was so tired that the crew would be able to kill the whale by stabbing it with blades and lances. The aggressive sperm whales would often fight back, with the famous example of a large male sperm whale fought back and sunk the 238 ton whaling boat the Essex in 1820, leading to the eventual deaths of eight of the twenty crew. This incident is thought to be the inspiration for Herman Melville’s classic 1851 novel Moby-Dick and the 2015 Hollywood film In the Heart of the Sea.

Global Sperm Whale

By the 1900s advancing technology such as steam-powered ships and explosive-tipped harpoons meant that sperm whales could be caught at an industrial level with much less risk to the crews of ships. In the years following the Second World War the numbers of sperm whales killed was in the hundreds of thousands – a completely unsustainable situation. By the end of the twentieth century, other sources of oil were becoming available and the value of sperm whale oil and blubber fell dramatically, making the hunting of sperm whales uneconomical in many cases leading the reduction in the intensive hunting of sperm whales.



Ambergris is a strange substance produced by the digestive system of sperm whales. Often described as ‘floating gold’ it is usually black, grey and yellowish in colour and wax-like in texture and is initially foul-smelling when it is expelled by the whales but takes on a sweet smell and smooth texture as it is exposed to air and sunlight. Ambergris has been used in the manufacture of expensive perfumes for many years and is therefore highly valued in the cosmetics and perfume industries. Ambergris can be worth thousands of pounds per kilogram – in 2015 a 1.1kg (2.4lb) lump of ambergris found on a Welsh beach sold for £11,000 at auction. Read our full article on ambergris by clicking here.

Conservation Status of Sperm Whales

Grand Ball Given by Whales
Grand Ball Given by Whales. A satirical cartoon in Vanity Fair, 1861, showing sperm whales celebrating the discovery of new oil wells in Pennsylvania. The increasing availability of crude oil reduced the value of whale oil and led to a reduction in the number of whales being hunted.

Today sperm whales are no longer hunted commercially. This species received international protection in the 1970s with all major whaling nations stopping hunting this species by the 1980s. Sperm whales are protected throughout the world’s seas and oceans and numbers of this species are stable and slowly increasing, although the low birth rate and long gestation period of this species mean that it will take a very long time for the number to recover to anything close to pre-commercial whaling levels. While sperm whales are not hunted today there are still a number of threats to this species such as sperm whales being caught up and killed in fishing nets and Japanese hunting whales under the guise of scientific research. The current threats to sperm whales mean that the IUCN classes them as Vulnerable globally and in Europe, while in the Mediterranean Sea they are classed as Endangered.