Sperm Whales are animals of superlatives

• They are the largest of the toothed whales. Males reach lengths of 20 m while females grow to 12 m.
• They are the most sexually dimorphic of cetaceans. At 44 tonnes, a mature male is over three times the weight of a 13.5 tonne mature female.
• They are the most accomplished mammalian divers. Dives of over an hour to depths below 2,000m have been recorded.
• Within their massive heads, which form up to a third of body length in males, is the largest sound-producing organ in the animal kingdom. Sperm whales are very vocal, producing loud clicks for most of the time they are underwater. Scientists and whale watchers often listen for whales using under-water microphones to find and study them. Sperm whales can be heard at ranges of five miles or more.
• They are extremely wide ranging. Sperm whales are found in deep waters in all the oceans of the world although females and their young are confined to tropical and temperate waters. Only the large males venture to the polar regions. Males may travel widely individuals have been tracked between Canada and Spain, and between the Azores and Iceland.
• They are very ecologically successful, exploiting populations of deep-living squid and fish, about which we still know very little. Before whaling, sperm whales were numerous, consuming more biomass than the world's entire fishing fleet.
• They have the lowest rate of reproduction of any mammal. Females mature at about 10 years of age. Gestation takes about a year and a half and suckling continues for several years. The average calving interval in stable populations is around 5 years. Calves are cared for communally and the oldest females, which do not seem to reproduce, contribute to calf care and may have a leadership role. Sperm whale populations were decimated by whalers and have been very slow to recover.
• The sperm whale has the most highly developed social organisation of any of the great whales. Females and their young live together in stable family groups of between 12 and 30 individuals.
• Perhaps most intriguing of all, sperm whales have the largest brains that have ever existed on earth.

Female sperm whales, and males less than about 6 years old, live in social groups. Members of a group may be spread over one kilometre or more of ocean and few whales may be visible at the surface at once. Male sperm whales may be found alone, accompanying female groups, or in bachelor schools. Male sperm whales may be observed off New Zealand, Iceland, Norway, Canada, and around Antarctica, for example; while female schools have been studied in the Indian Ocean, off the Galapagos Islands, Azores, and in the Caribbean

Female groups are likely if:

1. latitude <35 degrees, or
2. small whales (<9 m long) are present, or
3. more than two whales are clustered together at the surface, or
4. more than five whales can be heard clicking consistently through a hydrophone.

A female group is probably not present if:

1. latitude >45 degrees (55 degrees in N. Pacific), or
2. only whales > 12 m long are visible

You are in a whale watch area and may encounter whales and whale watchers at sea. Remember, whale watchers make their living from taking people to see whales and dolphins without disturbing them and they should operate to a strict code of conduct. If you disturb whales and dolphins you are depleting this resource and threatening the livelihood of whale watch operators.

Guidelines for Yachts:

• Never approach whale watching vessels
• If you encounter whales at sea:
  • put on your engine at low revs so that the whales know you are there and to provide manoeuvrability. NEVER sail up to whales
  • move slowly away from whales, or stop, and let them move away from you
  • never approach closer than 100 m
  • avoid making sudden changes in engine revs or going into reverse
  • if whales approach you, either maintain a speed and heading parallel to their direction of movement, or turn away.

Don't Panic. Unprovoked, whales do not harm yachts!

You can help to protect whales and their marine habitats.

• Never throw rubbish into the sea - ensure that it is disposed of properly.
• Plastics can kill wildlife including whales.
• Never release poisonous or noxious substances into the sea. This can harm whales, fish, plankton and corals.
• Always behave responsibly around whales.
• Report anyone behaving irresponsibly around whales and dolphins to local authorities, researchers or an appropriate conservation group.
• Reduce damage to important coastal habitats such as reefs and sea grass beds. Do not anchor on them or touch, collect or remove living or non living objects from them. Do not support the tourist trade in coral, shells, sponges or marine invertebrates such as star-fish, sea urchins, sand dollars.
• Support conservation, research and education initiatives.

Sperm Whales and Whale Watching