For most of the animal kingdom, survival is a hardwired instinct — reflexive action without thought. Genetic adaptation can be passed down through generations, but learned behavior is a trait seen only in animals of higher intelligence. We've known for years that whales display this type of intelligence.
When feeding, blue whales are known for performing a type of rolling ballet, executing barrel rolls in between feeding lunges. Scientists noticed a natural tendency to favor the right side, which is known as laterality, or "handedness." Just as humans are right- or left-handed, whales show a preference for one side or the other.
To learn more about the underwater habits of whales, University of California marine biologist Ari Friedlaender and his team attached 63 video cameras with accelerometers to the backs of blue whales over the course of six years. The cameras were attached with suction cups that were designed to release after a few hours and float to the surface so researchers could retrieve them.
It’s easy to get close to a whale, it’s hard to get close enough to put something on its back.
At lower depths, batches of krill are denser and the readings showed that whales tended to roll to the right. Toward the surface, where patches of krill are less dense, readings showed a tendency to roll to the left. Like most animals, a whale's eyes are connected to their opposite brain hemisphere, left to right and right to left. And as in humans, the left hemisphere of the brain is in control of precise functions.
For blue whales, whose eyes are at the side of their heads, Friedlaender believes the data suggest a reason behind the lateralization. Toward the surface where the whales need to be more precise to catch the less dense batches of krill, they'll roll to the left so their right eye is focused on their prey. The information processed by their brain's left hemisphere allows for more precise control when lunging forward.
These are not big animals mowing a lawn. They’re making decisions—they’re able to be flexible, and they need to be. We were completely surprised by these findings, but when considering the means by which the whales attack smaller prey patches, the behavior really seems to be effective, efficient, and in line with the mechanisms that drive their routine foraging behaviors.