Today we spent a lot of time in the company of three humpback whales, two big adults and a young juvenile, probably only a year old. When we first met them they were with another two whales which then split off and travelled on, while these three showed quite a lot of interest in us. They came within touching distance of the boat several times, or diving right underneath us, checking us out from all angles. The youngster in particular seemed very curious and he also displayed a few interesting behaviours such as tail lobbing, rolling at the surface and pectoral flipper waving.
The juvenile had quite distinct colouration and markings on his body, being slightly lighter grey in colour than the adults (indicating that he was still quite young). He also had a lot of scars and scratches on his body, especially on the tail fluke and dorsal fin, including some very prominent rake marks. Rake marks are very typical parallel scars that look a bit like if you had pulled a rake across the skin. They are very distinct from the half-moon-shaped scars left by shark bites. Instead, rake marks are generally caused by dolphin teeth, in this case by one of the larger dolphin species, probably orca. Orcas, also known as killer whales, are actually the largest of the dolphin species and one of the few animals that would actually prey on large marine mammals like whales. A big healthy adult whale doesn’t really have natural predators, but a young one or a sick / injured one would certainly be a target for a pod of orcas. Orcas hunt in groups, a little bit like a wolf pack, and have been known to attack whale calves, generally after a very long chase that involves separating the calf from the mother.
While we don’t usually see orcas in these waters, there have been several anecdotal reports of them being spotted in the area. Especially 60 years ago, in the early whaling years, when they were seen a lot more frequently, following the humpback whales which were plentiful back then. They probably stopped using this area after the humpback population crashed, due to whaling. So it will be interesting to see whether we will start seeing more orcas again now that the humpbacks are recovering so well!
The young humpback we met today, certainly seems to have encountered them, though luckily managed to get away with only a few scars to tell the tale!
Eco Ranger Ina
Tangalooma Marine Education & Conservation Centre