These mysterious giants roam the world’s ocean – the Pacific (and Western Pacific), Atlantic, Indian, Arctic and Southern Ocean basins. There are over 90 different species of Cetacea (whales and dolphins), all unique in their own way, including some that scientists know nothing about.
The Wonderful World of Whales
What all whales have in common is that, like us, they are mammals: they surface and breathe air through nostrils on their head, are warm blooded, and nurse and care for their young. Most large whales are migratory and spend summers feeding in the freezing polar ocean basins where they build up an insulating layer of fat known as blubber. Blubber also serves as their food supply in their food scarce winter tropical breeding areas.
Whales belong to the order “Cetacea” and are divided into two suborders, “mysticeti” and “odonotoceti”.
Mysticete whales are baleen whales and are unique in that they have a bristle-like structure of plates made of keratin – the same protein that makes up fingernails and hair – growing from their upper jaw. Baleen whales do not have teeth, instead, this structure is called ‘baleen’ serves the purpose of filtering food from water. These whales, while being extremely large, eat very small prey including zooplankton, krill, small crabs and small schooling fish. Mysticeti whales are also identifiable as both nostrils are visible leaving them with a double blow-hole opening on the top of their heads. There are at least 14 species of Mysticeti, divided into four families: Balaenidae, Balaenopteridae, Eschrichtiidae and Neobalaenopteridae.
Odontocete whales, such as dolphins, porpoises and sperm whales have teeth, and only a single blowhole visible (though they also have two nostrils in their skulls just like us). They generally eat larger fish, octopus, squid and larger crabs. Odontocetes have a sensory ability called ‘echolocation’ in which they produce sound, which echoes back off objects, in order to “see” objects, including prey.
Orcas, whilst referred to commonly as killer whales, are the world’s largest dolphins and are also grouped with this suborder. There are at least 10 families of Odontocetes which include dolphins, porpoises, river dolphins, sperm whales, beaked whales, and the narwhal whose spiral tooth looks like a unicorn horn. All species vary widely in size and characteristics but among them are some very well-known, very interesting, and even some unknown species.
The Blue Whale
The blue whale is the largest living animal in the world. It is a Mysticeti and belongs to the family Balaenopteridae along with the well-known humpback whale. The females of the species, being larger than the males, can grow up to 33 metres long and can weigh 150,000 kilograms. Their voices are almost as big as they are – their song is so loud and deep it is thought to carry up to a thousand kilometres through the ocean to reach others of the species.
The Bowhead and Right Whales
Right whales get their name from whalers who considered them the ‘right whales to catch’ as they were so easy to target – they swim slowly, stay close to shore and float once killed. The three species of right whales – Southern right, North Atlantic right, and North Pacific right, along with the Bowhead whale – are all Mysticetes and make up the family Balaenidae. Though much smaller than blue whales, Bowhead whales have the longest baleen of all whales, reaching four metres in length. Whilst Southern right and bowhead whales are rebounding, the North Pacific and Atlantic right whales are still critically endangered, each with fewer than 500 individuals left alive in each species.
The Gray Whale
Gray whales are also Mysticetes and are the only species in the family, Eschrichtiidae. They are relatively small for Mysticete whales, reaching about fifteen metres in length. Gray whales eat off the ocean floor, sometimes by lying on their sides. Interestingly, gray whales can be right or left-side dominant, like humans, and will lay on whichever side is dominant when feeding. These whales are sometimes referred to as the friendliest of all species because they often approach boats. Though, whalers sometimes refer to them as ‘devilfish’ after several of the species attacked their boats to defend their young.
The Sperm Whale
Sperm Whales are the largest Odontocete whales, making up the family Physeteridae. The males can reach 16 metres, whilst females only get to 11 metres – the biggest sex difference of all whales. They have around 40 teeth only in their lower jaw, each weighing up to a kilogram, and feed on giant squid. They are the easiest whale to spot as they are so oddly shaped, with large square heads, and their blow is bushy and angled, due to the position of the blowhole. Sperm whales are thought to be one of the deepest diving whales, holding their breath for over an hour and diving over a kilometre down.
The Northern Bottlenose Whale
Northern bottlenose whales are also Odontocetes and are the most well-known and studied of the family Ziphiidae, which is made up of about 22 recognised whale species. Most of these species are beaked whales, but the group also includes the northern bottlenose whales. These whales have large protruding foreheads and small stubby beaks similar to that of dolphins. Males of the species, interestingly, have been known to form friendships in which they associate with another male of similar age. In the 19th and 20th centuries, they were hunted often. As they are curious creatures and, due to their friendships, when one whale was killed they often stayed nearby it, making them an easy target. About 65,000 were killed in this time period and today, data is too insufficient to classify it.
Narwhals may be the strangest looking of all whales – often referred to as ‘unicorn whales’ due to the single long tusk protruding from the male’s heads. Narwhals are Odontocete whales and belong to the family Monodontidae along with the beluga whale. In the past, their tusks have been sold on the black market as mythical unicorn horns, and there is still a growing trade for their ‘ivory’. Narwhals live only in cold Arctic waters and are only up to five metres long while their tusks can grow two to three metres long – half the length of their body. The function of the tusk has long been debated, with some believing it to be a sensory organ. However, some males have been spotted using them to fight over females.
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