Sperm whale

Physeter macrocephalus

The sperm whale is by far the largest of the toothed cetaceans, comparable in size to some of the baleen whales. Male sperm whales reach a length of 16 metres or more and are considerably larger than females, which average less than 10 metres in length and reach a maximum of 11.5 metres. Sperm whales are dark grey-brown in colour, often paler around the belly, throat and mouth. The head is unmistakably square in profile, and can be a third of the entire body length. The lower jaw is underslung and relatively small and bears the sperm whale’s large teeth. The single blowhole is positioned on the left side of the head at the very front of the blunt snout resulting in a diagnostic blow that shoots forward at an angle. Following a deep dive, the explosive blow of a sperm whale can be heard from several kilometres.

The skin on the head appears smooth in comparison to the wrinkly, corrugated appearance of the rest of the body. The dorsal fin is more of a hump than a fin, and is set well back on the body. Behind it, smaller knuckle-like humps reach back to the tail flukes. Unlike the humpback whale, with which it may be confused from a distance, the sperm whale has broad tail flukes, with a straight edge and uniform colour.

Sperm whales seen off Fujairah include females and juveniles, suggesting that they may breed in the region. On one occasion a mature bull was seen with a female pod. Pods of sperm whales in the Arabian region may include over 50 individuals, but single animals or pods of 6-12 are more common.

Little is known about the status of sperm whales in the region. It is likely that their distribution is centered in the Gulf of Aden and Arabian Sea. Strandings are most frequent, however, along the Gulf of Oman coast, including at least one in Fujairah in 2012, the skeleton of which has been preserved. The reasons behind such strandings are unknown, but may include ship strikes.

This species is considered by IUCN to be vulnerable to extinction.