A group of marine biologists who used movement-sensitive tags to track movements of blue whales ( Balaenoptera musculus ) off the coast of California discovered that most have a lateralization bias; in other words, essentially right-handed or left-handed. The study appears in the journal Current Biology .
A blue whale ( Balaenoptera musculus ) peaks near a research boat. Image credit: Flip Nickin, Minden Pictures / Oregon State University / CC BY-SA 2.0.
Dr. Ari Friedlaender, lead author of the study and researcher at the University of California, Santa Cruz, and co-authors attached motion detection labels to 63 blue whales to capture how animals move while devouring their prey.
In total, the team collected data on 2,863 lizards to search for prey to find that animals approach their prey using two different rolling behaviors.
In some cases, they roll to the side and then back, rotating 180 degrees or less. In other cases, they enter a full barrel that turns the whole circle around.
Evidence shows that individual whales have a preference as to whether they rotate to the right or to the left.
The vast majority of whales showed a preference to roll to the right, similar to how many people show a preference for using the right hand.
But the whales also showed some flexibility in their approach. When the animals made a barrel in shallow water to attack a small group of prey from below at a steep angle, they more frequently turned left, going against their general preferences.
Artist's interpretation of the two types of feeding strategies by lateral orientation lunge: barrel and lateral rolls. The upper scheme (1) shows a barrel on the left side where the whale rotates 360 degrees during the capture of the prey. The bottom graph (2) shows a roll on the right side, where the whale rotates less than 180 degrees during the feeding event. The estimated visual angle of vision is shown as a white cone and shows that during the turn of the left side, the right eye of the whale is directed towards the prey until the onslaught is initiated (opening of the mouth). Image credit: Friedlaender et al. doi: 10.1016 / j.cub.2017.10.023.
"Most of the movements that we tracked involved 'skill' – maybe up to 90% – involved 90" poor quality side rolls, which is the way they feed most of the time " said Dr. Friedlaender.
"The blue whales approach a krill patch and set aside. We found many of them turned exclusively to their right, less rolled just to their left, and the rest exhibited a combination. "
The findings are the first to demonstrate a bias on the left side of a lateralized routine behavior. the adaptability of blue whales when it comes to feeding behaviors.
"We believe that this bias on the left side is the result of whales maintaining a visual connection with their prey with their right eye," said Dr. Friedlaender
"If the whales turned to the right as they approached, they would lose sight of their prey and diminish the ability to forage successfully. By turning to the left, whales can maintain this visual connection with their prey "
" As far as we know, this is the first example in which animals show different lateralized behaviors. according to the context of the task being performed, "said co-author Dr. James Herbert-Read, a researcher at the University of Stockholm, Sweden.
" The next step is to conduct similar studies on related species of whales to understand if the behaviors seen in blue whales also exist in them, "the scientists said.
" We are also developing new technologies to capture even finer details of the underwater movements of whales. "
Ari S. Friedlaender et al 2017. Context-dependent lateralized feeding strategies in blue whales Current Biology 27 (22): R1206-R1208 ; doi: 10.1016 / j.cub.2017.10.023