Blue whales became the biggest animals to ever live thanks to their ‘highly-efficient feeding strategy’ of sucking loads of tiny sea creatures through plates in their mouths
Blue whales are the biggest animal to ever live, and it is their special way of hunting and eating that has allowed them to reach such enormous sizes.
Baleen whales — the group to which blue and humpback whales belong — have long bristles in their mouths instead of teeth which act as giant filters.
These keratin structures allow the marine mammals to take in huge amounts of water, filled with plankton, krill and small fish in single gulps.
This extremely efficient way of eating allows them to take in more calories than their toothed cousins, such as orcas and dolphins, that hunt larger prey to survive.
A study has found that abundance of the diminutive food source is the limiting factor for the growth of baleen whales.
It found that the amount of krill present in the world’s oceans during the peak summer months restricts how large the animals can grow.
Scroll down for video
Baleen whales — the group that blue and humpback whales belong — have long bristles in their mouths instead of teeth, These keratin structures allow the marine mammals to take in huge amounts of water, flush with plankton, krill and small fish
Researchers found the mouths of baleen whales were much more efficient at capturing tiny plastic than toothed whales such as porpoises or dolphins (stock)
Baleen whales, also known as mysticetes, feed by filtering food using a hair-like material inside their mouth called ‘baleen’ (pictured) which exists instead of teeth
A study has found that baleen is an extremely efficient way of eating allows them to take in more calories than their cousins with teeth that hunt larger prey, such as orcas and dolphins
Their large size, achieved by eating huge quantities of food, then helps the animals as they grow.
Larger whales have wider mouths, allowing them to sift through more water and prey than smaller whales.
The size of these ocean-dwelling giants is only limited by the seasonal abundance of prey, the researchers claim.
‘The largest baleen whale species must reap the energy gains of krill patches in only a few of the most productive summer months at high latitudes,’ says Stanford University biologist Jeremy Goldbogen, who led the research.
‘Highly efficient filter-feeding strategies mean that these whales can build up fat stores that can then power their migrations across ocean basins to breeding grounds at lower latitudes that are leaner and provide much less food.’
Efficiency of the feeding method was put to the test by researchers who tagged and tested around 300 whales, porpoises and dolphins of various sizes out in the wild.
Abundance of the diminutive food source is the limiting factor for whales, with research finding that the amount of krill present in the world’s oceans during the peak summer months restricts how large the animals can grow
Researchersused long poles to attach temporary tags (pictured) on to the animals backs with suction cups that transmitted data back to the research team in a boat on the surface
WHAT DO BALEEN WHALES FEED ON?
Baleen whales mostly eat small creatures such as zooplankton and small fishes, which they come across in large swarms in the ocean.
All baleen whales have baleen instead of teeth which they use to collect shrimp-like krill, plankton and small fish from the sea.
These bristly baleen plates filter, sift, sieve or trap the whales’ favourite prey from seawater inside their mouths.
Baleen is made out of keratin, the same protein that makes up our fingernails and hair.
The baleen of the bowhead whale can be 13 inches (33 centimetres) long.
Baleen whales include the humpback, minke, fin and blue whales.
They have clearly visible throat grooves which allow their mouths and throats to expand and balloon out as they gulp mouthfuls of seawater and food.
They used long poles to attach temporary tags on to the animals backs with suction cups that transmitted data back to the research team in a boat on the surface.
Once in place, the high-tech devices reported on the animals’ movements as they submerged to feed.
Sonar devices in the surrounding waters and historical records of prey in whale stomachs were used to estimate the density of prey near each animal in the study.
Published in the journal Science, more than 10,000 feeding events were recorded and analysed.
It revealed that only filter-feeding whales evolved a hunting strategy that pushed the animals to the maximum size possible.
For other whales, if they get too big it is almost impossible for them to maintain their size.
These toothed whales use echolocation to forage and their feeding relies on catching one target at a time, which are hard to catch and deep underwater, requiring lots of air and energy to catch.
For the largest toothed whales, the energy spent trying to catch a meal is greater than the energy gained from eating it.
This places an upper limit of the size these animals can reach, a problem not faced by filter-feeding baleen whales.
‘They literally can’t eat enough to achieve a higher energetic pay-off before they have to return to the surface and breathe,’ Dr Pyenson said.
Filter-feeding whales evolved a feeding strategy that pushed the animals to the maximum size they can reach. For other whales, if they get too big it is almost impossible to maintain that size
Pictured: suction cup tags which are used on the whales. Efficiency of the feeding method was put to the test by researchers who tagged and tested around 300 whales, porpoises and dolphins of various sizes out in the wild
Once in place, the high-tech devices reported on the animals’ movements as they submerged to feed. Sonar devices in the surrounding waters and historical records of prey in whale stomachs were used to estimate the density of amount of prey near each animal
