Scientists capture rare footage of blue whales feeding off coast of New Zealand
Rare footage of blue whales feasting in the South Taranaki Bight has shed light on why the largest animals ever to exist on earth are such picky eaters.
The video, captured by scientists at Oregon State University, helps to prove the theory that the massive creatures, which can grow to the length of three school buses, only expend energy to catch prey they think are worth it.
"Modelling studies of blue whales 'lunge feeding' theorise that they will not put energy into feeding on low-reward prey patches," Leigh Torres, a principal investigator with the Marine Mammal Institute at Oregon State explained.
"We can see the whale making choices which is really extraordinary because aerial observations of blue whales heeding on krill are rare."
The video shows a blue whale cruise toward a large mass of krill about as big as itself before turning onto its side and swallowing the entire mass in one big gulp.
Another vignette shows the whale blast through a smaller mass of krill presumably not worth the effort of catching.
"It certainly appears that the whale determined that amount of krill to be gained, and the effort it would take to consume the meal wasn't worth the effort of slowing down," Torres said.
"It would be like me driving a car and braking every 100 yards, then accelerating again. Whales need to be choosy about when to apply the brakes to feed on a patch of krill."
The researchers found that whales approach thier feed at about 10.8 kilometres an hour, but opening their mouths to eat slows them down to about 1.8 kilometres an hour.
The team captured the video using small drones which flew above the whales.
"It's hard to get good footage from a ship," Torres said. "And planes or helicopters can be invasive because of their noise. The drone allows us to get new angles on the whales without bothering them."