I was lucky enough to celebrate Christmas and New Years in Cape Town, South Africa. While I was there I heard terrifying accounts of groups of Orca (Orca orca), or killer whales, invading the bay and wreaking havoc on populations of dolphins that inhabit the bay. This is a seasonal event, and watchers have seen thousands of dolphins being chased right across the bay by groups of killer whales working together.
The really striking thing about this is that killer whales aren’t supposed to eat dolphins. Dolphins and killer whales are quite closely related. IN FACT, killer whales aren’t really whales at all. They are giant dolphins! So it’s almost like cannibalism to think that the Orca have begun to eat their little cousins. In fact, marine biologists who are studying the event say that the first time this was recorded happening was in 2009.
Strange and terrifying apex predators, what really makes Orcas so deadly apart from their speed, size, and terrific sharp teeth; is that they hunt together in packs. Poor dolphins!
Even stranger to hear, marine biologists are reporting that great white sharks (Charcharodon, carchiaris) which have haunted swimmers on this beautiful coast for years; are leaving the bay. What could be dissuading them, there are still plenty of seals and penguins to eat? The answer might be also killer whale attacks. Great white shark carcasses have been found floating in the bay with the liver and pectoral fins ripped off. It is believed that Orcas gang up on Great whites, rip off their pectoral fins so that they can’t defend themselves properly, and then eat their liver while they are still alive. This is enough even to give the mighty Great white shark nightmares. Is this also a new behaviour? Or is it simply becoming more common?
So what is causing these radical changes in behaviour amongst Orcas? Are these really new behaviours, or are we only now becoming aware of them? There are no well documented cased of wild killer whales attacking humans. They have decided either that they like us, or that we don’t look very tasty. What if they change their minds?