Sperm Whale
Physeter macrocephalus
Similar species
At a distance, Sperm Whale blows may be mistaken for large baleen whales such as Sei Whale, Blue Whale, Humpback Whale, etc. If in deep water, this species is more likely. The logging behaviour is unique and the triangular tail shape and tendency to fluke up when diving are characteristic.
Identification
Sperm Whales are unmistakeable at close range. At the surface they appear log-like - it is very easy to mistake them for floating logs! They are dark brown in colour with a low triangular hump instead of a dorsal fin. The head is huge and the surface of the front half of the body is covered in prune-like wrinkles. Sperm Whales produce a prominent blow that is projected forward at an angle but in strong winds the blow of other species may appear similar. Sperm Whales have diagnostic diving behaviour. They rest apparently motionless at the surface (a behaviour that is referred to as logging) for about 10 minutes, breathing regularly every 10-20 seconds. Sometimes they will simply slip beneath the surface to dive but mostly just before a dive, the whale will first disappear then reappear with one large blow, strongly arch the back and throw tail flukes vertically in the air. The triangular shape of the tail is unique amongst large whales. Sperm Whales usually spend about 30-45 minutes feeding underwater, often surfacing within about three miles of the point of diving. Sperm Whales may occur singly, especially males in southern parts of the range; in small groups of bachelor males; and in large extended groups of 10-20 animals, comprising females and young, usually closer to the equator.
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