Sperm whale
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Physeter macrocephalus

Names

Azores : Baleia - POR : Cachalote - ITA : Capodoglio - SPAIN : Cachalote - GB : Sperm whale - GER : Pottwall NEDER : Potvis -SWEEDS : Kaskelot - NOORS : Spermhval. - DEENS : Kaskelot - JAP : Makko kujira

Biology

Adults' average size is 15 m, but they can reach a maximum length of 20 m and a maximum weight of 70 tons. Females are smaller than males with an average size of 11 m, reaching a maximum of 15 m in length and a maximum weight of 20 tons. The lower jaw of this species is V-shaped and has 17 to 25 pairs of robust teeth. There are no visible teeth in the upper jaw, but sometimes the sperm whale have small pairs of vestigial teeth. Newborns are 4 m long and weigh about a ton. The body is dark gray and the skin may appear wrinkled. The head, frequently covered by white scars that probably resulted from fights with other males or with giant squid, makes up 1/3 of the animal's total length. It is in the head that the famous spermaceti organ grows and this is the reason for the English common name. This species can live to 70 years old. They feed primarily on cephalopods (larger whales can eat as much as 1 ton per day), but they may occasionally eat a variety of fish. Gestation lasts 14 to 16 months and lactation can take as much as 1 to 3 years. Females bear a single calf every four to six years. Sperm whales emit pulsed clicks with varying frequencies (0.1 to 30 kHz) for echolocation and sequences of communication clicks known as codas.

Observation

The sperm whale is the cetacean with the highest frequency of observation in the Azores. We encountered them in 45 % of our ocean trips. The males are found year round in the Azores. The females and the calves are observed more frequently from May to October. This species cannot be confused with other species because of the distinctive bushy blow, up to 5 m high, that emerges forward at a sharp angle (about 45) from the head and toward the left. Excellent divers, the large males can reach depths of 3 000 m and stay submerged for about 1.5 hours without coming to the surface to breath. Females can only stay submerged for 40 minutes. The interval between dives is usually 5 to 15 minutes. When they do deep dives, they throw their tails high into the air (fluking). These animals can also remain on the surface for several consecutive hours when socialising or resting immobile. Cruise speed is 3 to 5 knots but, during whale hunting, there are reports of these animals swimming for a couple of minutes at speeds of 20 knots. Groups with more than 20 individuals are usually nursery schools containing females and calves of both sexes. Young males travel in small groups (with rarely more than 6 individuals), and older males are usually solitary.

Cetaceans in the Azores