One of the many whale-watching ships just out of Sydney harbour.
You can identify Humpback Whales by their single blow which is small, bushy and up to 4m high.
When watching for Humpback Whales look out for their characteristic 'hump', called the dorsal fin.
Whales need to surface for air every five minutes. These two Humpback Whales together look like a giant sea snake.
Whale-watching ships cruise the sea around Sydney in the peak season around end of June and early July.
This Humpback Whale is on its way north where they will breed and give birth to their calves, some 5,000 km from their summer area.
Watching a whale dive is a unique experience. The shape of their tails separates them from Southern Right Whales.
Markings on the tail fluke are black and white and unique like a fingerprint. No two markings are the same.
When Humpback Whales dive they arch their backs steeply which gave them their name. The dorsal fin is located 2/3 of the way down their back.
When in good mood, Humpback Whales entertain whale watchers by leaping out of the water and rolling in the air with their huge fins outstreched.
Adult Humpback Whales weigh up to 50 tonnes and reach lengths of up to 18 metres. Humpback whales are protected since 1965.
After whales surfaced they dive back into the water where they stay for around five minutes, sometimes longer.
Whale watching tours operate out of Sydney. In winter whales pass by Sydney much closer than on their return to Antarctica in spring.
When you watch this whale imagine that he's as big as three adult elephants. Humpback whales calf every two to three years.
A newborn calf weighs as much as two cars or two tonnes at birth. Calves need warmer waters to gain a thick layer of fat to protect them agains the cold.
Humpback Whales are just half the length of the largest animal known to live on earth - the Blue Whale.
When you compare the outline of a Humpback Whale with a 4-metre car you get a sense for the whale's size.