What are whales?

Whales are mammals. They are warm blooded, breath air through lungs and give birth to live young that are suckled on milk secreted from the mother’s mammary glands. Many of the features we associate with other mammals have been modified or lost during the long process of evolution from land dwelling ancestors and they have become superbly adapted to life in oceans, seas and rivers.

How many types of whales are there?

Whales, dolphins and porpoises, collectively known as cetaceans and are divided into two groups, the toothed whales or odontocetes and the baleen whales or masticates.

The toothed whales generally feed on larger food items such as fish or squid and include groups such as the river Dolphins, Dolphins, Porpoises, Beluga, Narwhal, Killer Whales, Sperm Whale, Pygmy Sperm Whales and Beaked Whales. There are around 72 species worldwide at present.

The baleen whales feed by filtering seawater to trap food such as planktonic invertebrates (e.g. krill), copepods, amphipods and small fish. They differ from the toothed whales in generally being larger, having baleen instead of teeth and having paired nostrils. The mysteceti include species such as the Gray Whale, Right Whales, Pygmy Right Whale and the rorqual’ a group that includes the Blue, Fin, Minkes, Sei, Bryde’s and Humpback Whales. There are around 13 species worldwide at present.

How many whales are there in Australia?

At present there are around 44 species recorded from Australia, 35 of these are toothed whales and 9 are baleen whales. Of the toothed whales, 19 species are from the family Delphinidae (including dolphins, pilot whales and Killer Whales) and 12 are from the family Ziphiidae (beaked whales). Also included are the Pygmy Sperm Whale, Dwarf Sperm Whale, Sperm Whale and Spectacled Porpoise. The baleen whales include the Southern Right Whale, Pygmy Right Whale and seven species of rorquals (a group characterized by the presence of long folds of skin behind and below the mouth). The number of whales species recognized worldwide and in Australia is constantly changing as the results of ongoing morphological and molecular studies become available.

What are whales closest relatives?

Because whales are so different from any land mammal it has been very difficult to determine their precise origins. Recent fossil discoveries and molecular studies indicate that hippopotamuses are the nearest living relatives of whales.

What do whales eat?

The large baleen whales (mysticetes) obtain their food by filter feeding using comb-like baleen plates that grow from the roof of the mouth. Prey is captured either by gulping large amounts of seawater and forcing it across the plates thereby trapping small food items, or by ‘skimming’ across the surface of the water and then removing trapped food with the tongue. Items such as krill, (shrimp-like crustaceans), copepods, amphipods, molluscs, polychaete worms, other planktonic invertebrates and schooling fish make up most of the diet of the baleen whales. The toothed whales (odontocetes) hunt and eat a wider range of larger food items including fish, squid, octopus, molluscs and polychaete worms. Some species, such as the Killer Whale eat other cetaceans, seals and sea otters.

Why do baleen whales have two nostrils and toothed whales have one?

Scientists believe there may be an evolutionary reason for this difference, perhaps in symmetry in the skull and the development of echolocation. Toothed whales echolocate, using their air passages to generate sounds (air is moved between sacs under the blowhole to generate high-pitched sounds) . We do not think that baleen whales use echolocation or, if so, to a much more limited extent. However, baleen whales do generate very low-frequency sounds that may allow for extremely long-distance communication.

How do whales breathe?

Whales are voluntary breathers meaning they have to consciously breath in and out (it’s not an involuntary reaction like we have). They swim to the surface to draw in air through their blowholes. Whales have limited breathing functions through their mouths. When a whale inhales, it fills up its lungs to capacity each time and then exhales 90% of its air supply with each breath. Humans exhale only 25% of their lung capacity. The whales exhale through the blowholes, a whole exhale in less than half a second and sometimes at over 300 mps, while inhaling takes place in a leisurely second.

Why are whales are often seen breaching, and flipper and tail slapping?

These activities performed by surface active groups are usually involved in breeding behaviors. Researchers think the males are competing for the chance to mate with available females. Some of the behaviors shown were breaching, flipper/pec (pectoral fin) slapping and tail slapping. Breaches and slaps, in addition to being aggressive displays during courtship, may also be a play behavior in juvenile and adult whales Breaches and slaps may also be used to remove pesky barnacles or old skin (a form of grooming).

What size can whales grow to?

For detailed information on the size, weight, mating, migration, feeding, history and status of each whale, visit our whale species guide below:

Whale Species

Below is a list of whale species and links to detailed information about each variety.