Discover all you need to know about sperm whales, from where they live to the sounds they make to communicate
Where do sperm whales live?
Sperm whales are found throughout the world’s oceans, preferring deep water. As a result they are seldom found close to land though Kaikoura off New Zealand’s South Island is one exception.
Why are they called sperm whales?
Sperm whales are named after the waxy substance found in their large heads called spermaceti. The spermaceti is an oil sac that helps the whales focus sound. Sadly, the oil was used widely in oil lamps, lubricants, and candles causing the whales to be targeted by whale hunters.
What do sperm whales look like?
The mighty sperm whales look nothing like any other whale. For a start, they each have an enormous square-shaped head which accounts for around a third of their body length. They have stumpy dorsal fins and two relatively small pectoral fins on either side of their wrinkle-covered bodies. Even a sperm whale’s blowhole is different, resulting in just a single exhalation which rises to the left. Perhaps their most recognisable trait though is their jaw, containing up to 52 cone-shaped teeth in the lower half, weighing a kilo each – thought to be used for aggression in males.
How many bones do sperm whales have?
As they feed at depth, their skeletons are adapted. For example, ribs are connected by a flexible cartilage that allows the ribcage to collapse rather than snap when it gets squashed at high pressure. Repeated diving to depth however can have long-term consequences and bones of adult sperm whales show signs of ‘pitting’, a sign of decompression sickness in humans.
How big are sperm whales?
Male sperm whales grow up to 19m in length, while females measure 12m and a calf 4.3m. Males weigh up to 57,000kg, females 15,000kg and calfs 1,000kg.
What do sperm whales eat?
Sourcing their food from the ocean depths, sperm whales use a highly advanced echolocation system that enables them to navigate in this murky, cold world. A firm favourite amongst sperm whales is the giant squid (some over 10m in length). Squid put up a good fight, and many whales carry the scars of their underwater encounters. More manageable smaller squid, octopus, fish and crustaceans are also appetising treats, as well as some deep-dwelling sharks.
How do sperm whales breathe?
Sperm whales can take a deep breath and dive to depths of up to 3km, then hold their breath for an incredible two hours.
Do they come to the surface for long?
Yes, they can spend significant time at the surface, logging and resting. They’re also known to sleep head-up hanging in the water.
How long do sperm whales live for?
Individuals can live to around 70 years old, if not longer.
Are sperm whales intelligent?
Sperm whales have the biggest brains of any animal, alive or extinct. Shown to possess a high degree of social complexity and culture.
What is their social organisation?
Females and their young form pods, whilst males (bulls) spend their time apart. Sometimes they group together to form bachelor groups but as they age they generally live solitary lives, only coming together to socialise and breed. Females, however, will live their lives as members of a strong social unit who will live and travel together and have their own acoustic dialect, called a ‘coda’. Unlike orca, these groupings do not have a strong genetic basing.
Do they interact with other species of whale/dolphin?
Rarely. Orca are known to predate on young calves whereupon the group form a ‘margarite formation’, where the vulnerable calf or pod member is protected in a circle by females with their heads facing inwards and their powerful flukes ready to strike out at any danger.
How do they breastfeed underwater?
Sperm whales breastfeed the same way other whales and dolphins do.
How long will the calf stay with its mother?
Social structures of sperm whales are not totally unlike that of humans. Young male sperm whales often hang out in groups until they are around 30 years old when they tend to go their separate ways. Females on the other hand like to spend more time together and join in ‘nursery schools’ to look after young, protecting calves from predatory sharks or orcas.
What sounds do sperm whales make?
Sperm whales make the loudest sounds of any creature. They can emit a click at around 230 decibels, considerably louder than a jet engine at around 150db. However, a sperm whale click only lasts 100 microseconds (a microsecond is 1 millionth of a second), whereas a blue whale’s call at 188db lasts 20 to 30 seconds.
What are the main threats to sperm whales?
- Pollution – toxic chemicals from plastics, litter and oil spills build up in sperm whales, seriously harming their health and their ability to have young.
- Fishing gear – sperm whales get accidentally caught in fishing nets and lines, injuring or even killing them.
- Noise pollution – sperm whales live in a world of sound and increased noise in the oceans from human activities impacts their lives.
- Hunting – sperm whales are still hunted on the island of Lembata in Indonesia.
What effect does plastic waste in the ocean have on them?
As with other whales and dolphins, plastic can entangle them and can be mistaken for food and so ingested, causing long-term issues. Microplastics floating in the ocean enter the food chain through ingestion by marine species like plankton, fish, dolphins and filter-feeding whales.
Are sperm whales endangered and how many are left in the wold?
They are listed as Vulnerable by the IUCN. It is estimated there are over 100,000 left.
What is the sperm whale’s scientific name?
Physeter macrocephalus
What is its classification?
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Physeteridae
Genus: Physeter
Species: P. macrocephalus
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Main image: Sperm whale © Getty images