When is a Whale not a Whale?
It is a common belief that whales, dolphins and porpoises are three different species of ocean-dwelling mammals. In fact, it is both simpler and more complicated than that!
At its simplest, all whales, dolphins and porpoises are collectively known as Cetaceans. the group or order to which they belong. However, the order Cetateans, in which there are over 90 species, breaks down into two sub-groups: baleen whales and toothed whales. They are differentiated by the number of blowholes (baleen whales have two blowholes and toothed whales one) and by how they feed.
For feeding, baleen whales have a set of comb-like bristles instead of teeth. They open their mouths and take in small creatures, such as small fish and krill, with the water. When the water pours out again, the food is caught by the baleen bristles and swallowed. Although a smaller group than toothed whales in number, baleen whales make up some of the largest whales in size, notably the blue whale, the largest creature known on planet Earth.
Most whales belong to the much larger group of toothed whales. As the name suggests, they hunt for their food rather than filter-feed. The group known as toothed whales in fact includes dolphins and porpoises, as they are toothed Cetaceans. The narwhal, a fascinating Cetacean, has what looks like a tusk, but is actually a redundant tooth! Biologists think that they use this tusk for seeing off mating competition. Orcas, although commonly known as killer whales, actually belong to the sub-group dolphins.
Do Whales Blow Water from their Blowholes?
It is common knowledge that whales rise to the surface to breathe air. However, the appearance of water rising from their blowholes is misleading. The blowhole leads to the whale’s lungs and is how it breathes. Although it looks like water, the famous spout is actually air being exhaled forcefully from its lungs. Because the air it exhales is warm, from being in its body, condensation forms in it when it touches the colder air outside its body. When the whale is back under water, the blowhole is kept closed by powerful muscles.
Are Killer Whales Dangerous to Humans?
Killer whales, which are actually of the dolphin group, are also called orcas, a diminutive of their scientific name Orcinus orca. They are certainly dangerous to other sea creatures which they hunt, even large creatures such as octopus, sea birds and seals. They hunt in well organised groups or pods, sometimes also hunting smaller whales, and it is this behaviour that could be the origin of their name killer whale. In times gone by, Spanish sailors, observing orcas killing whales, nicknamed them ballena asesina which means assassin of whales or whale killer. Eventually the two words became swopped around – killer whale! They are not generally though to be dangerous to humans. Rarely, they may mistake a group of resting people for basking seals, but generally back off once they realise. They can be more dangerous when in captivity in marine parks, occasionally attacking spectators. However, in this unnatural and stressful situation, this behaviour cannot be taken as an indicator of the creatures’ true nature.