Sperm whale

Research, threats and conservation status

Individual sperm whales can be recognised over time through crenulations and scarring on their dorsal fins and tail flukes. These photos are used to monitor individuals’ movements over time, estimate local population size and understand the social structure and population dynamics of the groups that are studied5-7.

Genetic sampling and the use of tags to monitor whales’ diving behaviour have been very important for understanding of sperm whale behaviour and populations 8-10 . More information about research techniques used to study whales and dolphins can be found here.

Natural Predators

Killer whales have been observed attacking sperm whale pods, and large sharks are also thought to be potential predators of calves. Sperm whales in some parts of the world have a unique response to attacks, gathering into a ‘marguerite’ or wagon wheel formation – in which all members of the group position themselves with their heads in the centre and their tails facing outward like the spokes of a wheel. They then fend off attack by slashing their tails back and forth. Sometimes a vulnerable calf or injured whale is positioned at the centre of the formation1,11.

Human-induced threats

Sperm whales face a number of threats today, including entanglement in fishing gear12-14, ingestion of fishing gear and marine debris15,16, and ship strikes17-22.   The latter is thought to be one of the main drivers of sperm whale population decline in the Mediterranean18,20,21, and a major threat to survival of sperm whales in the Canary islands17,19.

Conservation status

Sperm whales were historically heavily hunted, and today are globally designated as Vulnerable on the IUCN Red List of Threatened Species2.  The genetically distinct Mediterranean subpopulation, however, is considered Endangered, due to the fact that there are estimated to be fewer than 2,500 individuals and the persistent threats of ship strikes and entanglement throughout the area23.  Sperm whales are listed on Appendix 1 of the Convention on Migratory Species (CMS).

Sperm whales and whale watching

Please see the IWC Whalewatching Handbook