Lobtailing, Spyhopping and Breaching in Gabon
The sad story this week of a stranded humpback whale in Port Gentil, Gabon reminded me of encounters with these whales in the Baie du Cap Lopez (I wrote the following short account in 1997).
Humpback whales are regular dry season visitors to the coastal waters of Gabon. They are the most acrobatic of whales and have been said to have the most complex vocalisations of any animals after ourselves.
In 1987, after an oceanography conference in Woods Hole, I went looking for Humpbacks off Cape Cod. Their scientific name, Megaptera novaeangliae (big-winged New Englander) refers to their giant pectoral fins and common occurrence offshore Massachusetts and Maine. So, It was the right place to be looking. That trip was no disappointment, with several Northern Right Whales and a pair of Fin Whales (the second largest creatures on the planet, over 20m long) putting in appearances. Not a single Humpback showed, however.
13/7/97. Baie du Cap Lopez. This is why they’re called Humpbacks.
Since then I had seen many whales: hundreds of white Belugas in the Barents Sea, tens of Southern Right Whales off South Africa and dolphins and porpoises in the Pacific, Atlantic and Mediterranean. But, never a Humpback. Finally, in the dry season of 1997 a Humpback visiting the Cap Lopez Bay gave the full exhibition.
There’s a special vocabulary to describe Humpback acrobatics:
· Lobtailing, which means smacking the water with the tail. This view reveals the white underside of the tail. It may be a fish herding and stunning technique (or it could just be fun).
· Breaching, which means throwing most of the body out of the water then crashing down. This manoeuvre reveals the pleated throat (with 14 to 36 grooves) which expands like an accordion as it draws in water to pass through its baleen plates for food.
· Flipper waving. Up to about 4m of white flipper with knobbly leading edge is waved in the air and slapped on the water.
· Spyhopping. This means poking the head out of the water, showing the knobbly swellings on head and snout. Each of these bumps has one or two short hairs which are believed to act as sensors.
Our whale performed each of these moves, starting with some lobtailing, following with flipper waving and spyhopping and finishing with a spectacular sequence of breaches before moving out to sea.
13/7/97. Baie du Cap Lopez. The white underside of the tail is
about to be smashed onto the water in a lobtailing display.
In the 1970s it was discovered that all the humpbacks in a given area sing the same underwater song. Two to eight recognisable themes are repeated in the same sequence. Singers perform alone, within 50m of the surface with head down, flippers outstretched and body inclined at 45 degrees. It was once thought that humpbacks migrate north-south between permanent territories, but now it seems that they range widely over their entire area of distribution in a given ocean. The first evidence for this came from recordings of Hawaiian whale songs being sung by humpbacks that had travelled 3000 km to offshore Baja California.
A thought: at 12 to 15m (they sometimes reach 18m) that whale was about the length of a Tyrannosaur (but perhaps four or five times the mass). How long have there been whales in the oceans? The answer is a little over 50 million years. The earliest known whale (Pakycetus from the Middle Eocene of Pakistan, hence the name) lived about 10 to 15 million years after the last dinosaur. Long may they continue!
Post a Comment