Portal:Cetaceans/Did you know/Archive

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These are all of the Did You Knows previously selected for showing on the Cetaceans Portal main page. See also the List of all Did You Knows (add any you find to that page).

[edit] October, 2006

• ...dolphins often leap clear of the water when travelling at speed. This is because the density of water is much greater than that of air and they are able to travel faster by leaping out of the water.

• ...both whales and dolphins carry ‘whale lice’ — small crustaceans that inhabit folds in the skin of whales and dolphins, feeding off the loose skin.

• ...whale and dolphin mothers ‘suckle’ their young underwater! Mothers have muscular mammary glands and ‘squirt’ their milk into the calf’s mouth, to ensure that the calf takes in as much of the energy rich milk as possible.

• ...on average, a whale or dolphin will eat four to five percent of its body weight in food per day. That means that a 100 ton blue whale will eat almost five tons of krill per day, or that a 200kg bottlenose dolphin will eat 10kg of fish per day!

• ...newborn cetacean calves ‘suckle’ three to four times each hour and will suckle from their mothers for six months or more.

[edit] November, 2006

• ...when right whales and humpback whales breach (leap out of the water), seagulls can often be seen darting in to pick up pieces of skin that become dislodged from the breaching whales. Presumably this is an easy source of food for seagulls.
• ...whales and dolphins don’t sleep in the way humans do. Although we don’t know how they sleep, some scientists believe they sleep with half the brain asleep and half the brain awake, keeping them aware of danger.
• ...all whales and dolphins have the remains of the pelvis, but it is reduced to two small bones at the rear of the animal.
• ...the ‘strapped-toothed whale’ whale is so called because in mature males there are only two teeth in the bottom jaw and these completely ‘strap’ the upper jaw, preventing it from opening more than a few centimetres. How these animals eat is unknown, but it may be that they stun their prey with high intensity sound.
• ...some cetaceans can dive to depths of more than a kilometre and stay there for more than an hour.

[edit] December, 2006

• ...common dolphins, which are often seen off South Africa’s east coast, can occur in schools of several thousand. The biggest school on record was estimated to consist of about 15,000 dolphins!

• ...because whales and dolphins are streamlined to swim in water, they do not have external organs. This makes it almost impossible to tell the sex of a whale or dolphin when watching them on the sea surface.

• ...there are probably types of cetaceans that are as yet unknown. For example, the Longman's beaked whale is only known from skulls washed ashore in Somalia and Australia. It has never been seen alive!

• ...in baleen whales females are bigger than males, while in the toothed whales the males are bigger than females.

• ...the open mouth of an adult southern right whale can be two metres wide!