Monday, 25 May 2020
There are 15 species of baleen whales. They inhabit all major oceans, in a wide band running from the Antarctic ice edge to 81°N latitude.
Humpback whales are rorquals, members of the Balaenopteridae family that includes the blue, fin, Bryde's, sei and minke whales. The rorquals are believed to have diverged from the other families of the suborder Mysticeti as long ago as the middle Miocene era. While cetaceans were historically thought to have descended from mesonychids— which would place them outside the order Artiodactyla— molecular evidence supports them as a clade of even-toed ungulates — our dear Artiodactyla. Baleen whales split from toothed whales, the Odontoceti, around 34 million years ago.
It is one of the larger rorqual species, with adults ranging in length from 12–16 m (39–52 ft) and weighing around 25–30 metric tons (28–33 short tons). The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. It is known for breaching and other distinctive surface behaviors, making it popular with whale watchers.
Both male and female humpback whales vocalize, but only males produce the long, loud, complex "song" for which the species is famous. Males produce a complex song lasting 10 to 20 minutes, which they repeat for hours at a time. All the males in a group will produce the same song, which is different each season. Its purpose is not clear, though it may help induce estrus in females.
Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 km (16,000 mi) each year. They feed in polar waters and migrate to tropical or subtropical waters to breed and give birth, fasting and living off their fat reserves. Their diet consists mostly of krill and small fish. Humpbacks have a diverse repertoire of feeding methods, including the bubble net technique.
Humpbacks are a friendly species that interact with other cetaceans such as bottlenose dolphins. They are also friendly and oddly protective of humans. You may recall hearing about an incident off the Cook Islands a few years back. In September of 2017, Nan Hauser was snorkeling and ran into a tiger shark. Two adult humpback whales rushed to her aid, blocking the shark from reaching her and pushing her back towards the shore. We could learn a thing or two from their kindness. We've not been as good to them as they've been to us.
Like other large whales, the humpback was a tasty and profitable target for the whaling industry. They were nearly hunted to extinction before the process was banned back in the 1960s. While stocks have partially recovered to some 80,000 animals worldwide, entanglement in fishing gear, collisions with ships, and noise pollution continue to affect the species. So be kind if you see them. Turn your engine off and see if you can hear their soulful cries echoing in the water.