Sperm whale

ORDER: CETACEA

SUBORDER: ODONTOCETI

FAMILY: PHYSETEROIDEA

GENDER: PHYSETER

SPECIES: Physeter macrocephalus (Linnaeus, 1758)


Capodoglio, sperm whale, cachalote, cachalot, Pottwal

capodoglio01

The sperm whale is the largest of the Odontoceti, with an average length of 18 meters and a weight of 50 tons. The female is smaller (about 11m).  Characteristic of the species is the profile of the enormous head. The color is uniform dark gray only along the outside of the upper and lower jaw, the skin is often white. The breather is located in the head, shifted to the left and the breath is low, messy and directed obliquely forward with an inclination of about 45 °. The dives is reaching over 3000 meters. Before diving the sperm whales spends in the surface for 10-20 minutes, then arches his back pulling out the big tail. The social structure of the sperm whale is built around a social group, it’s composed by females and offspring individuals of both sexes; recent genetic studies have shown that these groups are formed by one or more permanent matrilineal units.

capodoglio02

Within the group, social relationships between individuals are stable and the offspring are bred for many years. The females seem to remain in the group of birth for life, males however, once they reach the "maturity" (between 15 and 21) are turning away from mothers to form herds of "bachelors" (bachelor groups). With ageing the sperm whales tend to isolate themselves, the big old males are often solitary (lone bulls) and aggregate reproductive groups only during the mating season. With its pelagic habits, sperm whales approaches the coast only where it has a bottom steep. This species is cosmopolitan in Italy and it is present both in the North West of the Mediterranean basin and in the Tyrrhenian Sea, where it tends to feed and reproduce. The sperm whale feeds on mesopelagic cephalopods, tuna, barracuda and demersal species such as cod, hake and medium-size and large weeverfish. The species, due to the continuous commercial exploitation for the economic value of its meat, is thinning. In the Mediterranean, the mortality data for the high rate of collisions and bycatch in fishing gear are alarming.