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HUMPBACK WHALE FACTS
What is really cool about humpback whales?
Humpback whales make extensive seasonal migrations between high-latitude
summering grounds and low-latitude wintering grounds.
Male humpback whales produce a long-series of calls often called "songs"
that can usually be heard during the winter breeding season, although
song components are sometimes recorded during the summer as well.
Researchers are unsure why humpback whales sing. It could be to attract
females or to notify other whales that they are in the area.
The most amazing part of humpback whale songs is that the whales create
themes and may repeat the same song for hours, broken only by pauses for
breath.
Humpback whale songs can last for 20 minutes and they sometimes repeat
the song for hours.
Some humpback whales feed by making "bubble nets" around their prey.
Several whales blow bubbles through their blowholes and swim in a circle
pattern so that the prey is trapped in the center of the "net." Then the
whales swim right up through the center of the bubbles and ingest the
prey.
Where do humpback whales live?
Humpbacks are widely distributed in all oceans, ranging from tropical
wintering grounds near islands and continental coasts to open-ocean temperate
and sub-polar summering habitats.
How can I identify a humpback whale?
They are 15.2 meters long--about as long as a school bus. Humpback whales
are mostly black or gray (although they sometimes appear brown) with the
undersides of their flukes, flippers and bellies white.
They have two blowholes, a small dorsal fin, and long flippers.
Humpback whales are extremely active and do lots of flipper and fluke
slapping and tend to breach more than any other baleen whale species.
How well can a humpback whale see or hear?
It is thought that baleen whales (including humpback whales) have excellent
hearing, especially at low frequencies, which is valuable in the dark
ocean environment where vision is less useful.
What do humpback whales eat?
Humpbacks are baleen whales, which means they filter their food through
baleen plates. They consume krill, anchovies, cod, sardines, mackerel,
capelin, and others sorts of schooling fish.
Some humpbacks have a very unusual way of catching their food. They make
nets to catch their prey called "bubble nets" with the air that they release
from their blowholes.
The whales dive deep then swim up in a spiral pattern, all the while releasing
a steady stream of bubbles.
As the bubbles rise they form a bubble cage, which traps the fish or plankton
that the whales are pursuing.
Then the whales swim up through the center of the bubble cage with their
jaws open and capture a great gulp of food.
How do humpback whales have their young?
Humpback whales are probably old enough to mate at about 7 years of age.
Females are pregnant for about 11 to 12 months and get pregnant approximately
every two to four years. Calves are born able to swim and can grow 1.5
feet (0.5 meters) per month while nursing.
Females nurse their newborn calves in warm, shallow water.
Humpbacks have very complicated courtship behaviors and many male humpbacks
can surround a female and compete with each other to get close to the
female.
Sometimes the competition involves males lunging at and bashing into each
other.
At the end of the mating and calving season, humpback whales migrate to
cold, productive waters to feed.
How long do humpback whales live? Why do they
die?
Because of an absence of teeth (which can be used to estimate age in
other mammals), it is difficult to tell the age of a humpback whale. Life
expectancy for humpback whales may be up to 80 years.
Humpback whales die of natural causes and are sometimes preyed upon by
killer whales. Pods of killer whales have been known to attack humpback
whales throughout their range, especially young animals during migration.
Humans commercially hunted humpback whales for oil, meat, and apparel
materials (for corset stays, umbrella ribs, buggy whips etc.) from the
17th to early 20th centuries.
Today, indigenous hunters practice subsistence whaling on a small-scale.
Humpback whales may also be harmed by pollution, ship strikes, or entanglement
in fishing gear.
The humpbacks are by far the most common whales to be found in Australian
waters.
It is believed that as many as 100,000 existed before white settlement
and the commencement of whaling in Australia.
By the time whaling ceased in Australian waters in 1962, only 200 were
left.
The present population has built up from those 200 humpback whales to
an estimated 3000 making the annual migration to northeastern Australian
waters this year.
Humpback whales take their name from the habit of breaking the water surface
with a large area of their backs when diving.
They are the fifth largest animal on this planet, growing to a size equivalent
to 11 elephants or 600 humans each!
Humpbacks are the most acrobatic of all of the great whales displaying
a wide variety of leaping, rolling and breaching movements, which provide
fascinating viewing for whale watching humans.
Adult humpbacks have been seen to breach 20 - 30 times in succession,
averaging only 10 seconds between breachings.
Humpbacks are also known for their complex underwater vocalisations or
whale songs particularly during breeding.
According to marine biologists, humpback whales (Megaptera novaeangliae)
spend the warmer summer months in Antarctic waters feeding on krill.
As winter approaches they start their annual migration north to the central
and southern Great Barrier Reef.
Calves are born in the warm waters of the Great Barrier Reef and then
commence their first migration with their mothers back to Antarctica.
Along with dolphins; humpback whales are cetaceans, a family of marine
mammals. More specifically, they are baleen whales, which means they feed
by straining their food from seawater through a series of plates on their
upper jaws.
They strain out plankton and very small crustaceans called krill from
the water.
This is their only food, so it is clear that humpback whales present no
danger to humans or other large life forms by their eating habits. Only
their tremendous size can present a danger to boats or swimmers that venture
too near.
Although there are laws to control how close boats and swimmers may go
to whales, there are no such laws that stop them coming up really close
to the boats to look at the people.
Growing to a length of 15 metres, humpback whales can weigh up to 45
tonnes.
They have a massive head that they are fond of popping high up out of
the water to get a good one-eyed look at the humans.
This behaviour is known as a spy-hop. Along the underside of their body
they have up to 22 throat pleats running from their chins to their navel.
Yes, whales do have a navel because, as mammals, they were once attached
to their mother by an umbilical cord.
These cetaceans have a very rough and ragged appearance once you get up
close, with many knobs and lumps on their skin, liberally interspersed
with barnacles.
Other outstanding features of the humpbacks' appearance are their huge
pectoral fins, which can be up to a third the length of their entire body,
and their huge tail flukes.
These body-parts are featured in some of the most interesting of whale
behaviours: pectoral fin extension, pec slapping, and tail slapping.
The Blow:
The first sign that whales are around is usually the blow. Humpbacks breathe
through the blowhole on top of their head.
When it expels its breath, the resulting burst of air and water vapour
can be seen for as far away as two kilometres on a clear day. The breath
rushes out at speeds up to 450 kph and can go up to a height of 5 metres.
It has a fishy smell and has sufficient oil content to put an unpleasant
smear of oil on a camera lens if the photographer gets too close.
Breaching:
A much more spectacular way of announcing its presence is for a whale
to breach.
With 2 or 3 beats of its huge tail the creature can hurl itself up through
the surface, sometimes clearing the water completely, and then fall on
its back with a tremendous splash.
Breaching is thought to communicate position to others. The splash can
be heard for several kilometres.
Head Lunge:
When the whale falls forward instead of backward the action is called
a head lunge.
Spy Hop:
Humpbacks are curious, and often pop their head up above the waterline
to look at whale watching boats with one eye.
The creature raises its head vertically from the water until the eyes
are exposed, maintains that position for a short period of time and then
lowers its head back into the water.
This common behaviour is thought to be used mainly for looking at their
surroundings when orientating themselves with the shoreline during migration.
Pectoral Fin Extension:
Humpbacks are often seen waving their huge oar-like fins above the water.
The creature lies on the surface and lifts one or both of its pectoral
fins up out of the water depending on body position.
Once extended the fins can be waved about.
Tail Extension:
Sometimes humpbacks are seen with their tail flukes extended above the
water for up to 15 minutes at a time.
This behaviour is rare but could be to do with feeding, as a calf is often
seen bobbing around its mother's tail at this time.
Tail Slapping:
Whales like to lift their huge tails high above the water and slap them
down on the surface making a tremendous splash.
This can be heard for great distances by others and is probably associated
with marking position.
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