Dolphins and Whales of the Great Barrier Reef
Due to its warm waters which hold an abundance of food and feeding grounds, the Great Barrier Reef is a huge attraction for marine mammals including large numbers of dolphins and whales looking both for a place to feed and for sheltered areas to bring their young. You can expect to find about 30 different species of whales and dolphins in the Great Barrier Reef’s borders, with Humpback and Dwarf Minke whales along with Bottlenose dolphins being among the most common.
Probably the most iconic of all Australian whales in terms of sheer recognition, the Humpback is a popular drawcard due to not only their numbers but also for
their propensity to perform spectacular breaching and tail-slapping displays which has made them a favourite of most whale watching tours and tourists from not only around Australia but worldwide. The Humpbacks, whose name is derived from the “humping” motion they make when diving back down below the surface, perform an annual migration between the waters of the Antarctic where they feed then head up north to the Great Barrier Reef’s more tropical waters to give birth and raise their children. Humpbacks grow from 12 – 16 metres in size upon reaching adulthood and can usually be spotted on the reef from locations such as Cairns and Port Douglas, making both of these popular tropical destinations a valid place to take part in some whale watching if you are so inclined. Humpbacks spend their time in the Great Barrier Reef mostly for relaxation and play – having stocked up on a steady diet of krill and other forms of fish while in the Antarctic – letting their new calves build up body fat which for insulation which they will need to survive upon the return back to the Antarctic’s icy seas.
While frequently hunted back in the 1940s through to the early 1960s during which time Humpbacks had their numbers greatly depleted, in recent years after whaling has ceased their numbers have begun a steady climb once again, with a jump from numbers as low as 500 during the peak era of whaling to an estimate of 10,000 as of 2008. Multiple environmental groups have taken strong stands against whaling and for conservation of not only the Humpback but also many other groups, and it looks likely that their numbers will continue to increase in the coming years.
Dwarf Minke Whales
In the whale world, being called a “dwarf” is definitely a relative term – the Dwarf Minke Whales that can be found in the waters of the Great Barrier Reef still average just under eight metres in length, with a weight of up to five tons. Dwarf Minke whales, much like the Humpbacks, are a fairly social creature and will often approach boats and other marine vessels out of curiosity which makes spotting them – despite their relatively few numbers – quite an easy task. Dwarf Minkes are distinct from their larger cousins not only due to their slightly smaller size but also due to different bodily markings which are clearly visible. Common differences in colourations that can be found on the Dwarf Minke whale include white shoulder and flipper bases, grey tips on their flippers, and large dark patches which line their throats. Around 200 individual Dwarf Minke whales make their way to the Great Barrier Reef each season, with their distinctive markings making it quite easy to recognise individual members of the whale pod.
As with the Humpbacks, Dwarf Minkes were also once targets of a thriving whaling industry; this has likewise been curtailed since regulations were put in place. Natural predators may also play a small factor as due to their slightly smaller size than the average whale, they become a target for such ocean predators as tiger or great white sharks or killer or false killer whales. Their relatively small calves are also particularly vulnerable to attack, which can make the parents especially protective of their young.
With an uncannily “friendly” looking face and an inherently playful nature, Bottlenose dolphins are always favourites due to their ease and frequency of interaction with humans. Wide in number, Bottlenose dolphins can be found in cold-temperate to tropical seas all over the world, and are extremely intelligent creatures in general. As powerful swimmers, Bottlenose dolphins show an innate ability to escape from predators due to a combination of smarts and a top swimming speed of around 37 kilometres per hour. Due to their social nature, Bottlenose dolphins tend to travel in large groups and can be frequently seen accompanying tour boats that head out to the Great Barrier Reef, surfacing and cackling or playing in the wake of the ship and occasionally leaping out of the water in spectacular fashion. Bottlenose dolphins grow to a maximum size of around 4 metres in length, and have a dark grey complexion near their top fin that then becomes lighter towards their underbellies.
The diet of the Bottlenose dolphin consists of a variety of smaller fish and marine life including squid, crab, prawns and other smaller creatures, and are renowned for their teamwork in rounding up prey much like herding farm animals. In order to locate their food, the dolphins use a form of “natural sonar” based on echoes and use it to determine both the location and distance of their potential target – yet another reflection of their intelligence. In fact, due to their smarts, dolphins have shown an easy ability to respond to training from humans and are thus a fixture at many popular marine-based theme parks throughout the world where they can be seen performing spectacular stunts.