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Cuviers Beaked Whale

Cuviers Beaked Whale

Ziphius cavirostris

Physical description http://web.archive.org/web/20070314035827/www.whaledolphintrust.co.uk/whales_dolphins/images/cuviers_W.jpg
Also known as the goose-beaked whale this is one of the most widespread and abundant of the beaked whales. However, it is not often seen at sea and is mostly known from strandings. Colouration ranges from brown to grey or purplish-black with a lighter belly and very often paler around the face. Scars are common on males which have a single pair of teeth in the lower jaw. These two teeth are often covered in barnacles suggesting that they are not used for feeding and their overall colour fades with age. The forehead slopes gently to a slight beak and the head is often visible as the animal swims. The small, falcate dorsal fin is positioned well back on the body. It has small, rounded pectoral fins and large, tapered flukes.

Distribution

The Cuvier’s beaked whale seems to be a very cosmopolitan whale, although its distribution is mainly known from strandings and there are a relatively small number of sightings. It is absent only from polar waters, being found in all tropical and temperate waters all around the world. It is also quite common in enclosed seas but seldom seen close to mainland shores.

Behaviour


Cuvier’s beaked whales travel alone or in groups of about 10 individuals. Their blow is directed slightly forwards and to the left but it is low and inconspicuous. It is most often seen when the animal returns to the surface after a long dive which may last for up to 40 minutes. Before deep dive they typically arch their back steeply and sometimes raise their tail. Breaching has only been observed very occasionally.

Breeding

Since they are so seldom seem alive, very little is known about their breeding behaviour. The males are known to fight using their two small teeth on their lower jaws and this is presumably for dominance in access to females. The gestation period is about twelve months and the young are born in late summer to early autumn. Males become sexually mature when they reach about 5.5 metres and females when they reach 6.

Feeding

Cuvier’s beaked whales are known to dive deeply to fish for squid and other cephalopods and deep-sea fish. They appear to hunt alone.

Current situation
As with all the smaller cetaceans, one of the threats to the Cuvier’s beaked whale is still the hunting being carried out in Japan and South America for meat for human consumption and for bait for crab fisheries. They are also caught in fishing nets and lines. Since their major prey is squid they will swallow things which resemble a swimming squid, such as plastic bags. These are known to get stuck in their gut and eventually cause their death. A Cuvier’s beaked whale washed up on Mull, off the west coast of Scotland had been killed by the enormous amount of black plastic from silage and haylage bags, which it had ingested.