cat-right

Northern Bottlenose Whale

Northern Bottlenose Whale

Hyperoodon ampullatus

Northern Bottlenose Whale Illustration; Copyright Caroline Lathe / HWDT

Physical Description

The northern bottlenose whale has a very distinctive large, prominent forehead and a dolphin-like beak. The bulbous forehead is particularly large in adult males who may grow up to 9.8 metres long. Their bodies are long and cylindrical with a small falcate or triangular dorsal fin well back along the body. The broad tail flukes have concave trailing edges but no notch and the pectoral flippers are small and pointed. Juveniles are quite dark with greyish white undersides but they become paler as they age becoming grey and brown with a paler belly. Many of the northern bottlenose whales have a definite band of paler skin in a crescent around their neck. Some males show signs of scarring from fights and most males develop 2 sharp teeth.

Distribution

The northern bottlenose whale is a deep water cetacean and is normally found only in waters deeper than 1,000m especially just beyond the continental shelf and above submarine canyons. They are most common in the northern waters from Nova Scotia up to Iceland and show seasonal migratory movements. There is particular spot called “The Gully” about 160km off eastern Nova Scotia where the bottlenose whales are commonly found feeding on the rich plankton and squid in this deep canyon.

Behaviour


The northern bottlenose whale has an intense interest in ships and a habit of remaining close to injured or distressed companions. This led to their population being greatly depleted by whaling and they are officially classified as vulnerable. They can stay submerged for a long time – more than one hour and maybe up to two and lift their tail flukes before commencing such a long, deep dive. Most dives last between 15 and 60 minutes and their blow is clear and bu shy. They make a complex range of calls and use their superb sonar to hunt at depth. Their sounds are also used for communication and they are very sociable animals enjoying playing and touching one another.

Breeding

They form small mixed herds numbering 5 – 15 but segregate according to gender at different times of the year. The females become mature at about 8 to 12 years of age and the males about a year earlier. They are thought to live for about 37 years. Long-term relationships have been observed among whales of the same sex but not among mixed sexes.

Feeding

Using their well developed sound systems they dive to great depths to hunt squid and other invertebrates. They also hunt fish but lack the teeth to consume large fish.

Current situation

Because of their very curious nature the northern bottlenose whale was easy to hunt and has been hunted more than any other beaked whale. Tens of thousands were killed especially between 1850 and 1973 reducing the population to a vulnerable level and since 1977 the species has been protected. Their “friendly” behaviour may also help their survival since they are very easy to study and allow whale-watchers to approach without disturbance.