The secret life of whales
Whales are fascinating creatures that developed from land mammals about 55 million years ago. They belong to the group of animals called ‘Cetacea’, which also include dolphins and porpoises.
We’re pretty lucky in Australia—over 50 percent of the world’s cetaceans are found in our waters. This includes over 45 species of whales, dolphins and porpoises that visit or live permanently in Australia. Some species like the orca are found throughout Australia, while others such as beaked whales are much more elusive.
In fact, some whales are so elusive that we only discover information about them if they become stranded. Here are some facts we do know about these majestic creatures.
Which whale is it?
There are two different types of whales: toothed whales (odontoceti) and baleen whales (mysticeti). Toothed whales have teeth or tusks, while some feature a long, spiralled horn like a unicorn. Toothed whales have a single blow hole on the top of the head, which was formed when one of the nostrils became dominant over the other.
Toothed whales tend to eat squid, octopus, crustaceans, fish and occasionally other marine mammals. The largest of the toothed whales is the sperm whales, with males growing up to 18m long and weighing 50t. Other whales in this group include orcas, beaked whales and dolphins.
Instead of teeth, baleen whales have plates of keratin, which hang from the roof of their mouth and filter plankton, krill and schooling fish. Humpback whales, southern right whales, minke whales and blue whales are all examples of baleen whales.
For more information on whale species, and to log your sightings download the Wild About Whales smartphone app.
Giants of the ocean
One of the reasons whales are so fascinating is their sheer size. The blue whale is the largest animal to have ever lived on earth, ruling the ocean at up to 30m in length and more than 200t. Their tongues alone can weigh as much as an elephant and their heart, as much as a car.
Other whales are just as impressive. The southern right whale is longer than a bus at 15m and can weigh around 63t, while the humpback whale grows up to 18m in length and can weigh up to 50t. Minkes are the smallest and most abundant baleen whales in Australia, growing to around 9m and weighing up to 6.8t. Find out more about the different species here.
Songs of the whale
Whales sense their surrounding environment through sound. They make a range of sounds including moans, squeals, howls and cries that are complex and can continue for hours. These sounds travel great distances underwater. Toothed whales can use sound to echolocate their prey. Pings and clicks are transmitted through the water until they reach an object, then bounce back to the whale to reveal its location, size and shape. Sperm whales hunt giant squid in the darkness of the ocean depths in this way.
Scientists have studied the songs of whales and believe they are used to communicate, hunt and attract potential mates. Each pod has its own distinctive noises that its members will recognise, even from very far away.
A coastal playground
Whales are quite active in the water and display a range of spectacular behaviours, from breaching and lunging to waving and slapping their pectoral fins and tails on the surface of the ocean. They can also raise their head above the water to look around and extend their tail fluke in the air for up to 15 minutes at a time. Mothers and their young calves often touch each other with their flippers, in what seems to be gestures of affection.
Experts believe that some of these behaviours help to work out their position in relation to land, or allow them to communicate with other whales. Fin slapping may also be a warning of danger nearby. Another theory is that whales launch themselves out of the water and fall back with a splash to rid themselves of skin parasites. Of course, they may just be having fun!
The great migration
After the female whales give birth in northern tropical waters, they travel south with their calves to Antarctica, (normally around September to November in NSW) where they can find a bountiful supply of krill to eat. Along the way, they hug the NSW coastline and may linger in harbours and estuaries, as whale mums teach their calves to feed and interact with other marine life, while protecting the calf from predators.
*Have you spotted any whales along the NSW coastline? Don’t forget to log your sighting with the Wild About Whales smartphone app and share your best pics on Facebook or Twitter using the hashtag #whaleon.