The fifth largest animal on Earth

Humpback whales are easily recognised by their long narrow fins. ©Getty Images

Humpback whales are easily recognised by their long narrow fins. ©Getty Images

Humpback whales are baleen whales.  The humpback whale is the 5th largest animal on earth, growing to a length of 15 metres and weighing up to 45 tonnes. They are the most commonly seen whales in Australian waters, but are found in all the world's oceans. They migrate each year from winter in the polar regions to warmer waters closer to the equator.

Humpback whales have a massive head. Along the underside of their necks they have up to 22 throat pleats which expand when they are feeding. They have a very rough skin, with many knobs and lumps on which barnacles grow. Humpbacks have huge pectoral fins which can be up to a third the length of their entire body. Their tail flukes are huge. Each half , left and right,  of the tail is called a fluke.

A breaching humpback whale. © Getty Images

A breaching humpback whale. © Getty Images

Humpbacks get their name from their habit of showing a large area of their backs out of the sea as they dive.

They are the most acrobatic of all of the big whales, leaping, rolling and breaching (leaping right out of the water and falling backwards, making a loud noise as they hit the water), which provides great viewing for humans.  Adult humpbacks sometimes breach as many as 30 times in a row, every 10 seconds or so. They are inquisitive, and often lie on their backs with flippers in the air, or with heads out of the water, looking around above the surface.

Singing

Humpback whales are famous for their complicated whale songs, particularly during breeding season. The songs are series of cries, clicks, howls and other noises, which can go for hours. The sound travels great distances through the water. Scientists are not sure why they sing, but it is probably to attract a mate and to communicate with other humpback whales.

Humpback whale with calf. ©Getty Images

Humpback whale with calf. ©Getty Images

Humpback whales spend the summer months in polar waters feeding on tiny krill and plankton. They make a 'cage' of bubbles to trap krill, then feed.

Humpback whale's flukes. ©Getty Images

Humpback whale's flukes. ©Getty Images

As winter approaches, they start their migration north to warmer waters, many going to the central and southern parts of the Great Barrier Reef of Australia. Calves are born in the warm waters. The calves suckle milk from a teat in a fold on the mother's belly. Whale milk is very rich so that calves gain weight and grow a layer of blubber before they begin the long migration with their mothers back to the cold polar water.  Many migrating humpback whales stop off at Platypus Bay, a shallow, sheltered bay that is part of the Hervey Bay Marine Park.

Conservation Status and Threats

Humpback whales are now classified as Vulnerable. It is believed that as many as 100,000 humpback whales existed before European settlement and the commencement of whaling in Australia. Humpback whales were easy prey for shore-based whalers because they swim close to shore.   By the time whaling in Australian waters stopped in 1962, only 200 were left. Humpback whales have been protected since 1963, and their numbers have increased. The present population making the annual migration to north-eastern Australian waters is an estimated 3,000. It is believed that worldwide the numbers are about 25,000.

Read more about the humpback whale.

http://australianmuseum.net.au/humpback-whale

Listen to some humpback whale songs here.

http://www.learner.org/jnorth/tm/hwhale/SingingHumpback.html

Watch a video about humpback whales in the northern hemisphere:

Whale of a Meal