Between July –September each year the Whitsundays are a vitally important breeding ground to about 30 species of whales and dolphins (or ‘cetaceans’). Some of the most commonly sighted whales are the massive humpbacks which make the trek to the Reef’s warmer waters from Antarctica between May to September to court, mate, give birth or rear their calves.
What do they eat?
These whales are found near coastlines, feeding on tiny shrimp-like krill, plankton, and small fish. Humpbacks migrate annually from summer feeding grounds near the poles to warmer winter breeding waters closer to the Equator.
Why do they leap from the water?
Humpbacks are powerful swimmers, and they use their massive tail fin, called a fluke, to propel themselves through the water and sometimes completely out of it. These whales, like others, regularly leap from the water, landing with a tremendous splash. Scientists aren’t sure if this breaching behavior serves some purpose, such as cleaning pests from the whale’s skin, or whether whales simply do it for fun.
How often do Whales breed?
The female Humpback whale typically breed every two or three years. The gestation period is eleven months, yet some individual whales can breed in two consecutive years. A Humpback Whale calf is about 4-4.5 metres in long when born and weichgs approximately 700kg.
How do the mothers look after their calves?
Mothers and their young swim close together, often touching one another with their flippers with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves leave their mothers at the start of their second year, when they are typically 9 metres long. Calves do not stop growing until they are ten years old.
How do whales reproduce?
Both males and females reach sexual maturity around the age of five. Full adult maturity is achieved at around 15 years. Competition for females is usually fierce, and unrelated males dubbed escorts frequently trail females. Groups of two to twenty males gather around a single female and exhibit a variety of behaviors over several hours to establish dominance of the group of whales (rather like a night out in Airlie Beach). Group size goes up and down as unsuccessful males retreat and others arrive to try their luck. Behaviors include breaching, fin-slapping and charging. Whale song is assumed to have an important role in mate selection; however, scientists remain unsure whether song is used between males to establish identity and dominance, between a male and a female as a mating call, or both.
Do whales sing?
Humpback whales are known for their magical songs, which travel for great distances through the world’s oceans. These sequences of moans, howls, cries, and other noises are quite complex and often continue for hours on end. Scientists are studying these sounds to decipher their meaning. It is most likely that humpbacks sing to communicate with others and to attract potential mates. Humpbacks may sing continuously for more than 24 hours. Only males sing, suggesting that one purpose is to attract females. However, many of the whales observed to approach a singer are other males, and results in conflict. Singing may therefore be a challenge to other males. Guests on board Derwent Hunter are some times treated to hearing the whale song through the hull of the ship when under sail.
How do they breathe?
The Humpback whale breathe air at the surface of the water through 2 blowholes located near the top of the head. Their blow is a double stream of spray that rises 3-4 metres above the surface of the water. The tail flukes of a humpback whale, which are lifted high in the dive sequence, have wavy rear edges.
How do we responsibly view whales to avoid distress?
It’s critical for their continued survival that their ‘nurseries’ are available to them, free from any harassment and stress which may lead to calf mortality. It is important that guests know that there are rules in place to protect the whales. As someone who shares the waters with the Reef’s precious cetaceans, you have a responsibility to help protect them and to keep safe distances.
By following these responsible practices when you’re in the vicinity of whales and dolphins, you’re not only playing a big part in their conservation but you’re also providing a safe environment to watch them.