It is one of my life’s goals to see a humpback whale. Seeing any kind of whale is a treat, but humpbacks are master acrobats, and seeing a whale like that breaching out of the water would just be so cool. When I do see one, I’ll be sure to have my camera with me and I’ll get an awesome picture to post on this blog, but until then I’ll have to be content with this post.
Humpback whales are found in a vast range around the world, in all oceans. Most populations are migratory, though there is a sedentary population in the Arabian sea. The whales spend their summers in cold arctic waters, migrating to warmer tropical and subtropical areas in the winter. Humpback whale migrations can be as long as 25,000 km in a year.
Like many baleen whales, humpback whales are very, very large. They can grow up to 16 meters in length and weigh around 36,000 kilograms. That’s pretty big. Humpback whales have proportionally the longest pectoral fins of any whale, though why the humpback’s fins are so long, we’re not entirely sure. One theory is that the long fins help with agility in the water. Another is that the fins assist in temperature regulation, something the whales need when moving between cold and warm waters during migrations.
Though humpbacks are massively huge, they feed on small animals, mainly krill and schooling fish. They eat frequently during the summer, and very rarely during the winter, instead living off their body fat. The whales use a number of different techniques to capture prey, the most famous being bubble net feeding.
This system requires the cooperation of a number of different humpback whales. The whales swim in circles under the water, blowing bubbles to encircle a school of fish or krill. As they swim, the whales make the circle smaller and smaller, which makes the school tighten into a small ball. This is easy eating for a humpback whale, which will swim up the centre of the bubble net and swallow thousands of fish.
Another incredible aspect of humpback behaviour is their song, which is among the most famous of any whale. Male humpbacks are responsible most of the humpbacks’ singing. They can make incredibly loud noises, which can last for up to 20 minutes. Humpback whales will sing for long periods of time, sometimes for over 24 hours. The songs are specific to geographical locations, with all whales in an area singing the same song, though these change over time, so that a song is not the same from one year to the next. The exact function of humpbacks’ songs is unclear, though the songs may be issued as a challenge to other males, or to attract females for mating.
Males and females migrate to tropical waters to breed. Gestation in humpback whales is just under a year, meaning that female humpback whales have to migrate back to the tropical areas to give birth. During this time they don’t eat, and must finish their pregnancies, give birth, and nurse their calves, all while fasting. They suckle their babies for six months, before heading back to their feeding grounds. Calves stay with their mothers for a year, making at least one migration to feeding grounds with her. It only takes that one time, and the calves are hooked for life; they will return to the same feeding ground their mother showed them for the rest of their lives.
Whales have always fascinated me, and I think it’s pretty easy to see why. These incredible, gigantic animals are so amazing I love them more and more each time I learn about them.
Cover image source: http://www.challengertlh.com/imax/humpbackwhales.html