Why are whales special? They live their whole lives in water and have a lot of amazing qualities. Although they couldn’t look more different than human beings, we have so much in common!
Whales are social, air breathing mammals, they feed their babies with their own milk, and they take extraordinarily good care of their young and teach them life skills.
Many of us believe whales are special; they certainly invoke a sense of wonder and a feeling of kinship. There is something almost other-worldly about them. Whales enrich the lives of many people who come into contact with them. Whales are unique, beautiful, graceful and mysterious; they nurture, bond, play, sing and cooperate with one another. Here are some extraordinary facts about whales and their lives in the oceans.
How many species of whales are there?
There are currently around 90 recognised species of whales, dolphins and porpoises; they are collectively known as ‘cetaceans’ or simply ‘whales’. There are 15 baleen whales, 3 sperm whales, 23 beaked whales, 2 monodontidae (narwhal and beluga), 42 oceanic dolphins (including 4 river dolphins) and 7 porpoises.
Cetaceans are broadly divided into two groups, depending on whether they have teeth (odontocetes) or baleen (mysticetes).
Baleen whales are sometimes called the ‘great whales’ due to their overall larger size. There are 15 baleen whales altogether: these whales have baleen plates in their mouths to sift their food - plankton, krill (little shrimps) and small fish - from seawater.
Toothed whales account for all the remaining species of whales, dolphins and porpoises and they all have varying numbers of teeth. Toothed whales eat mainly larger fish, squid, octopus and at times, other marine mammals.
So which cetaceans do we call ‘whales’? It isn’t very scientific but whales include all the baleen whales and the larger toothed whales such as the sperm whale, beluga, narwhal, and the beaked whales.
How do whales feed?
Baleen whales and toothed whales feed very differently. Baleen whales extract their prey from seawater as it flows through, or is forced through their baleen plates using their tongues and sometimes their throat muscles. They eat mainly small shrimplike krill, copepods and fish.
Baleen is made out of keratin, the same protein that makes up our fingernails and hair, and so it is strong and flexible. Hundreds of overlapping baleen plates grow downwards from the roof of the whale’s mouth, like multi-layered curtains. The number, size and colour of the baleen plates are unique for each whale species.
Baleen whales are all essentially filter feeders but their feeding techniques vary; the humpback and blue whale are gulpers – they open their mouths wide and gulp enormous mouthfuls of seawater, their prey gets caught amongst the baleen plates as the seawater is pushed back out through them. Bowhead and right whales are skim feeders, they swim along with their mouths half open, allowing sea water to flow through their baleen and trap plankton. Gray whales swim on their sides along the bottom of the ocean floor and suck up mud and water; they use their baleen to filter out tiny crustaceans from this sludge.
Toothed whales (and dolphins and porpoises) all have teeth - the number, size and position of their teeth varies from species to species. They hunt mainly fish, squid and octopus using their sophisticated sonar systems – echolocation – to find and target their prey. Toothed whales generally use their teeth to grab and hold on to their prey before swallowing it. Some may also use their teeth for tearing and breaking up prey. Some beaked whales have only two to four teeth, they are squid eaters and are thought to suck in squid and swallow them whole.
Which whale has the biggest teeth?
Male narwhals definitely win the prize for the longest tooth. They grow one canine tooth, or tusk, which sticks straight out at the front of their mouths and grows up to 3m (9ft) long – it looks just like a jousting lance used in modern-day competitions. The narwhal’s sword-like tusk grows in a counter clockwise spiral and pokes right through the upper left-hand side of the mouth. The narwhal’s tusk is thought to be a male sexual trait similar to the antlers in male deer or the mane of a male lion. Very rarely, a female narwhal will grow a tusk or a male will grow two tusks. Ironically inside their mouths, narwhals do not have any teeth at all!
The whale with the biggest full set of teeth is the sperm whale. Sperm whales have 40 to 52 cone-shaped teeth, up to10 to 20cm (4 to 8in) long, in their narrow lower jaws only. Each tooth is heavy and weighs as much as one kilogramme.
Biggest toothed whale
Sperm whales are the biggest toothed whales. Males are much bigger than females and grow up to 19.2m (63ft) which is a bit longer than a ten pin bowling lane or as volley ball court, and can weigh up to 57 tonnes (57,000kg or 125,664lb).
The largest brain on Earth belongs to the sperm whale. The volume of their super-sized brains is 8000 cubic centimetres, which is more than five times the volume of ours - 1300 cubic centimetres. A sperm whale’s brain weighs up to 9kg (almost 20lbs) which is the weight of a small dog and 6 times heavier than a human brain.
In evolutionary terms, we humans have only had the big brains we do now for about 200,000 years; in contrast, the current size of the sperm whale brain has changed little from that of its cetacean ancestors, which evolved some 55 million years ago.
Sperm whales have huge heads – they account for up to a third of their overall body length. Most of the space inside their heads is taken up not by their brains but by a large cavity filled with yellowish fine oil called spermaceti. This oil was valuable to whalers who sold it for oil lamp fuel, to make candles, creams and ointments. The sperm whale’s unique spermaceti organ plays an important role in echolocation (whale navigation and ability to ‘see with sound’).
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