Portal:Cetaceans/Did you know/Archive

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).

October, 2006

A Bottlenose Dolphin Breaching the water

...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.

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’ 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.

December, 2006

A Common Dolphin

...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!

January, 2007

Orcas breaching the water

...the Orca, is the fastest swimmer of all the cetaceans and can reach speeds of more than 50km/h while hunting.

...some cetaceans can dive to depths of more than a kilometre and stay there for more than an hour.

...newborn cetacean calves do not have the skills to swim for long periods or to accelerate away from danger, so they swim in the slipstream of their mothers, enabling the mother to protect her calf.

...all cetaceans have a blubber layer — a layer of fat under the skin. In most dolphins, this layer is about one quarter to one third of the total body weight, but in southern right whales nearly half of its weight (up to 50 tons) will be blubber.

...most whales and dolphins live long lives. Wild bottlenose dolphins live well into their forties, while some of the larger whales live in excess of 80 years!

February, 2007

...the male narwhal's tusk can be up to 3 metres in length and weigh up to 10 kilograms.

...observations of cetaceans date back to at least the classical period in Greece, when fisherpeople made notches on the dorsal fins of dolphins entangled in nets in order to tell them apart years later.

...groups of bottlenose dolphins around the Australian Pacific have displayed basic tool use by wrapping pieces of sponge around their beaks to prevent abrasions. This is a display of a cognitive process similar to that of great apes.

...Herman Melville's novel Moby-Dick had real-life inspiration, a notorious male sperm whale named Mocha Dick.

...the Voyager Golden Record carried into space whale songs, among other sounds.

March, 2007

The Voyager Golden Record

...the songs of whales were sent into space aboard the Voyager spacecraft to represent sounds from Planet Earth.
...the Beluga whale is also known as the Sea Canary on account of its high-pitched squeaks, squeals, and whistles.
...Orcas are versatile predators with many populations actively hunting down whales such as the Grey Whale.
...the Sperm Whale, at 18 metres long, is the largest toothed animal to have ever lived.
...in spite of their enormous mass, baleen whales are capable of leaping completely out of the water, particularly the Humpback Whale.

April, 2007

Baleen from a baleen whale.

...the Humpback Whales song is produced by them forcing air through their massive nasal cavities

...baleen from the Mysticeti whales mouths was used to stiffen parts of women's stays and dresses, like corsets

...the Sperm Whale was named after the milky-white substance spermaceti found in its head and originally mistaken for sperm.

...the Beluga Whale's milkfat is so high, the calf gains up to 2 kilograms per day on the diet. It is so fatty that the colour is green.

...the Blue Whale has the largest penis of any animal on earth, estimated at over 2 m (more than 6½ feet)

May, 2007

...Qi Qi was the name of one of several captive Baijis held at the Wuhan Institute in China in an attempt to rescue the species.
...the Beaked whales (genus Ziphidae) contain over twenty species of small whales, and are the least known of all cetaceans.
...The ear bone called the hammer (malleus) in cetaceans is fused to the walls of the bone cavity where the ear bones are, making hearing in air nearly impossible. Instead sound is transmitted through their jaws and skull bones.
...cetaceans with pointed beaks have good binocular vision, but others, such as the Sperm Whale cannot see directly in front or behind.
...Migaloo is an albino Humpback Whale often spotted off the east coast of Australia.

June, 2007

A dead Atlantic Northern Right Whale after colliding with a ship propeller.

...the leading cause of death in North Atlantic Right Whales is injury sustained from colliding with ships.
...the Spade Toothed Whale is the rarest, and probably the most poorly known large mammalian species.
...the ear bone in cetaceans is fused to the walls of the bone cavity where the ear bones are, making hearing in air nearly impossible. Instead sound is transmitted through their jaws and skull bones.
...from its discovery by John Edward Gray in 1850 until a re-assessment in 1981, the Clymene Dolphin was regarded as sub-species of the Spinner Dolphin.
...the Australian Snubfin Dolphin (Orcaella heinsohni) is a recently recognised species of dolphin first described in 2005.

July, 2007

A Hector's (Maui's) Dolphin

...that the Maui's Dolphin is the most endangered subspecies of all marine mammals, with only 100 estimated to remain.
...the melon is an oval shaped oily, fatty lump of tissue found at the centre of the forehead of most dolphins and toothed whales, located between the blowhole and the end of the head.
...the sperm whale family, or simply the sperm whales, is the collective name given to three species of whale, the Sperm Whale, the Pygmy Sperm Whale and the Dwarf Sperm Whale.
...the word Vaquita, a species of porpoise, means little cow in Spanish.
...a beached whale is a whale which has become stranded on land, usually on a beach.

August, 2007

A Harbour Porpoise.

...that while the main predators of the Harbour Porpoise are Great white sharks and Orcas, Bottlenose Dolphins have been witnessed attacking and killing porpoises in response to a lessing food supply.
...Aboriginal whalers are permitted to hunt cetaceans, despite the IWC's memorandum on commercial hunting.
...the melon is an oval shaped oily, fatty lump of tissue found at the centre of the forehead of most dolphins and toothed whales, located between the blowhole and the end of the head.
...the Spinner Dolphin is so called because of its acrobatic displays in which they will spin longitudinally along their axis as they leap through the air.
...that the Tay Whale was a Humpback whale unlucky enough to be spotted near Dundee, Scotland, then the UK's premier whaling port, in early December, 1883.