Here’s some important life advice: Don’t try to challenge a small-finned pilot whale (Globicephala macrorhynchus) For a squid eating contest. Research today shows that these marine mammals can carry hundreds of live calamari a day.
For the first time, a large international team of researchers has quantified the diet of short-finned pilot whales living in the waters near Hawaii. They found that a single whale could eat up to 200 squid a day, while whales in the area could collectively eat about 416 million squid per year. Researchers say that despite the huge numbers, local squid populations are doing well, as are the whales that feast on them.
“Fortunately for us and for the pilot whales, squid reproduce rapidly and have high growth rates, which means that pilot whales have a reliable food source at least some of the time,” William Gough, a postdoctoral researcher at the University of Hawaii at Manoa’s Marine Mammal Research Program and lead study author, told Gizmodo.
lack of data
Gough and his team weren’t really trying to solve the diet of these whales, at least not at first.
They were initially hoping to learn more about false killer whales (Pseudorca crassidens) in the area. But tagging these animals – actually a species of dolphin – proved more difficult than they expected. During their futile attempts to track the false killer whales, they ran across a large group of pilot whales offshore. These encounters ultimately gave him the idea for a new study aimed at filling the gaps in what we know about these whales.
“We did a little digging and, as it turns out, the Hawaiian population of short-finned pilot whales is considered ‘data deficient’ by the International Union for Conservation of Nature,” Gough said. “Therefore any additional data on their movements or behavior could greatly benefit conservation and management efforts of this species in Hawaiian waters.”
The short-finned pilot whale is one of two species of pilot whale (the other species – the greater shocker – is the long-finned pilot whale). They are commonly found in tropical and temperate waters around the world, with about 8,000 whales living near Hawaii. Although their population numbers are generally strong, they still face some man-made threats, such as strikes by ships, entanglement in fishing gear, and climate change, the latter of which may push them further into northern waters.
Whales subsist primarily on a steady diet of squid, although their exact calorie requirements – and how much squid they would need per day to meet these needs – was a mystery until now.
How much does a pilot whale eat?
To figure out a short-finned pilot whale’s calorie intake, the team had to combine data from a variety of sources, Gough says, including movement data from short-lasting tags, daily feeding rates from satellite tags, body measurements collected via aerial drone, and scooping the stomachs of unlucky whales stranded on land.
Once the team collected all this data, they estimated that a typical whale would eat 82 to 202 squid a day. To meet its energy needs, a whale must consume an average of 140 squid per day. Annually, this amounts to approximately 74,000 squid per whale. For all the whales in the area, this amounts to about 88,000 tons of squid eaten each year.
The team’s findings were published Thursday in the Journal of Experimental Biology.
diet tracker
This research isn’t just providing some new trivia to share with your whale-loving friends.
According to Gough, the techniques the team developed to calculate the diets of these whales can also be used for other whales and dolphins. And they plan to study much more further.
“Over the past 10-15 years, researchers have created some really impressive tag and drone datasets for a variety of whale and dolphin species, so we are looking forward to following up this current study using our comparative analytical framework on species ranging in size from harbor porpoises to blue whales,” Gough said.
That all sounds great. I just hope scientists never try to figure out how many wings I eat during MLB baseball season.