Blue whales primarily feed on krills --small, shrimp-like creatures-- and they do so in small groups. A new study regarding these creatures' diet has revealed that they could be hunting near the surface of the ocean to preserve their strength. Watch the scene in a video captured by a drone.
Researchers from Oregon State University discovered that blue whales residing in New Zealand utilize surface hunting as a crucial part of their process.
Blue whales are the largest mammal ever to walk the earth, surpassing even the size of dinosaurs from prehistoric eras. And to support their size, they require a massive amount of food every day.
The researchers believe the mammals prefer to hunt their prey where they are more densely packed, such as the surface of the water.
Massive vs. Tiny
The process of hunting in shallow waters give the whales the benefits of avoiding the tiring process of diving and provides a large amount of food to be consumed at once. They are also able to save energy due to not having to stay underwater and thus not needing to hold their breaths as they usually would.
Assistant professor at Oregon State University and author of the study, Dr. Leigh Torres, shared her response to the misconception that whales have to dive deep to find their prey. Dr. Torres corrected this by saying if the animals can hunt on the surface, they would gladly do so to converse their energy.
With the observed group of whales in New Zealand, they were observed to favor hunting in shallower areas of water, where their prey would be more compactly knit together.
The team observed the animals as they hunter and noticed shorter dives and more feeding at the surface.
Scientists placed tags on blue whales to monitor and keep track of their routes and where they go to study their patterns to understand these majestic creatures better.
Before the study, surface feeding wasn't fully understood, primarily due to the difficulty in processing the data from the tags when the whales reside near the surface of the water.
Dr. Torres' team observed the behavior during a field research study as they were watching from their boat, where they used a drone to capture the footage of the whales from overhead.
The theory of the team for the unconventional feeding technique stems from denser populations of krill near the surface, thus enabling the whales to get more food with less energy.
The difference between the hunts
Studies showed that New Zealand whales have much shorter dive times compared to other species, up to a quarter of the usual time, which reduced even further when surface feeding was observed.
The video shows the animals in their natural habitat hunting for food, and noticeably planning their attack on the unsuspecting marine creatures. The whale could be seen looking at the krills with its right eye before going in for the massive gulp. The giant mammal also showed signs of rotating from one to the other, contemplating how to go about the kill.
The observation has filled a unique mystery in the field of marine biology, said Dawn Barlow, co-author of the study. She is also a doctoral student in Dr. Torres' laboratory.
The researchers were also able to estimate the width of the opening made by the whale's mouth just before the moment of impact.
The observations also gave the researchers an in-depth look into the whole process of capturing the krills, and the techniques they utilize to feed successfully better.
The team published their findings in the Peer journal and reiterated the importance of using drones in allowing us to see more of what we couldn't see before.