Pilot whale

  (Globicephala melas)
Pilot whale

Description: The body in Pilot Whales is robust, with a thick tail stock. The melon is exaggerated and bulbous and the beak is barely discernible or non-existent. The dorsal fin is wide, broad based, falcate and set well forward on the body. The flippers are long, slender, and sickle-shaped, typical of this species. Its size and shape are depending on the animal age and sex, being the dorsal fin more bulbous in males than in females; and also thicker and wider. Female dorsal fin is then straighter. Pectoral fins, nearly head situated, are extremely long (18%-27% of the total body length) and sickle-shaped.

Pilot Whales coloration is dependent on the age. Young individuals are brownish or light grey, while adults are black or dark grey. A grey midventral line extends to the front into an anchor-shaped chest patch and widens to a genital patch.

A pale eye blaze is visible in one fifth of all adult pilot whales, most often in males. Males often have pots or scars on the body.

Size: On average, the flippers reach 18-30% of the body length in long-finned pilot whales. Adults reach a body length of approx. 6.5 m. males being 1m larger than adult females. They can reach up to 2 tons in weight. The life span in females is longer than in males. Females can live 60 years, while males only 46-47 years.

Behaviour: Pilot Whales are highly social; they are generally found in pods of 50-60, but some groups contain up to 100 individuals. Based on photo-identification and genetic work, pilot whales appear to live in relatively stable pods like those of Killer Whales, and not in fluid groups like many smaller dolphins. They are social animals, with close matrilineal associations with 60% females. The pods are often mixed with Bottlenose Dolphins (Tursiopstruncatus). When travelling, pods may swim abreast in a line several kilometres across. Their tight social structure also makes Pilot Whales vulnerable to herding, and this has been taken advantage of by whalers in drive fisheries.

Entire pods can sometimes be seen logging, allowing close approach by boats.

Pilot Whales usually remain on the surface. Due to this fact, they are called"sleepers" by the fishermen. Many times they approach to the boats and elevate their heads to observe all around.

Pilot Whales can dive to 600 metres, although the majority of immersions are to 30-60 m, for 10 minutes.

Distribution: It is found in cold temperate to sub-polar waters of both hemispheres, being frequently seen along the edge of the continental shelf, although it can be seen near shore.

Feeding: Mainly squid eaters, pilot whales will also take small medium-sized gregarious fish, when available.

Reproduction: Mating occurs primarily in May-June and again at a lower rate in October. Calving and breeding can apparently occur at any time of the year, but peaks occur in summer and autumn. The gestation period lasts 15-16 months. At the time of birth, calves are 1.7-1.9 m. long and weight 75 Kg. and stay with the mother for 2 years or more. Calving interval is 4.5-5 years long. Females reach sexual maturity at 7 years old, while males at 12 years old.