What are whales?
types of whales are there?
many whales are there in Australia?
whales closest relatives?
What do whales eat?
Why do baleen whales have
two nostrils and toothed whales have one?
How do whales breathe?
Whales are often seen
breaching, and flipper and tail slapping. For what purpose are these
can whales grow to?
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 mysticetes.
The toothed whales generally feed on larger food items such as fish or
squid and include groups such as the river D
Killer Whales, Sperm Whale, P
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,
inkes, 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.
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What are whales closest
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.
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
baleen whales have two nostrils and toothed whales have one? Is there a
reason for the difference?
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.
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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.
are often seen breaching, and flipper and tail slapping. For what
purpose are these actions?
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).
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What size can whales grow to?
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(Images are not to scale)
|Dwarf Minke Whale
Size: 7 - 10m
Weight: 5 - 10 tonne
Size: 11.5 - 14.5m
Weight: 12 - 20 tonne
Size: 11.5 - 15m
Weight: 25 - 30 tonne
Size: 12 - 16m
Weight: 20 - 30 tonne
Size: 11 - 18m
Weight: 20 - 50 tonne
Size: 18 - 22m
Weight: 30 - 80 tonne
Size: 21 - 27m
Weight: 100 - 120 tonne
|Southern Right Whale
Size: 12 - 17m
Weight: 80 - 90 tonne
Size: 6 - 8m
Weight: 5 - 8 tonne