For killer whales in the tropical waters of the Caribbean, everything’s on the menu, even whales twice their size, according to new research led by FIU.
“They are the most apex predators,” said marine sciences assistant professor Jeremy Kiszka of FIU’s Institute of Environment.
They have no choice.
To survive, adult killer whales must eat hundreds of pounds of food — as much as 3 to 5 percent of their body mass — in a day. The warm waters of the Caribbean, while teeming with prey, don’t provide the same concentrations of prey as colder ocean waters. And when prey is more widely spread out, killer whales can’t be picky. They also don’t want to expend too much energy on a lengthy hunt.
It’s why In the Caribbean, killer whales have a taste for several other whale species, dolphins — and to a lesser extent — sharks, fish and sea turtles.
Still, they do have a preference for whales because whales carry lots of blubber and blubber is a quick way for killer whales to consume the energy they so desperately crave.
Researchers have noted that sperm whales, which can be up to twice the size of killer whales, are particularly aware of the danger.
“We found sperm whales with tooth rakes from killer whales,” Kiszka said. “Sperm whales also go close to shore when killer whales are in the area and they become completely silent when killer whales are around.”
Determining the diet of a species as elusive as the killer whale wasn’t easy. The international team of researchers used a combination of methods to gain insight into what was happening beneath the waves. They conducted stable isotope analysis of killer whale tissues at FIU’s CREST Center for Aquatic Chemistry and Environment and relied on interviews with local fishermen on the killer whale behavior.
The study was published in the journal Frontiers in Marine Science.