Do Whales Eat Krill? (Answered)

do whales eat krill

The blue whale is the largest animal to roam the earth, EVER! This ocean giant can be up to 25 feet long and weigh as much as 150,000lbs, far larger than any dinosaur.

An animal of this size needs to have an impressive diet, one that sustains and nourishes its large body and can provide enough fuel for them to migrate over oceans.

Blue whales are baleen whales, which means they have baleen plates hanging from their upper jaw in order to filter feed.

So what do these enormous whales eat? Sharks? Tuna? How about other whales? Nope, the answer may shock you.

An interesting question that often comes up when discussing whales and their dietary preferences is one that we’re going to cover in this post among others. “Do whales eat krill?”

YES, whales eat TONS of krill every single day. Baleen whales use their baleen plates to sieve out krill and other crustaceans from seawater as they feed. Their mouths expand like a balloon to gobble up around 500kg of krill in a single mouthful!

How Much Krill Do Whales Eat?

Baleen whales that feed on krill eat ALOT of it. Many baleen whales consume around 4 percent of their body weight per day, this can be as 4 tonnes of krill daily in some species.

During the feeding season when whales travel to the icy waters of Antarctica, there are 5 different species of krill that can be found, offering an abundant source of food for whales.

blue whale
Image: NOAA Photo Library

Antarctic krill is actually one of the most abundant and successful animals on the planet with some schools of krill being as dense as 30,000 individuals per cubic meter.

That’s a lot of krill!

Why Do Whales Eat So Much Krill?

Whales eat lots of krill because it is the most abundant food source in Antarctica. It helps them pack on the weight they need to survive the winter months when they travel to their breeding grounds.

They’re also perfectly adapted to catching krill, plankton, and other small crustaceans thanks to their unique adaptation.

Baleen whales get their name because they have baleen plates that hang from their upper mandibles.

They also have a flexible jaw that allows the whales to scoop up thousands of krill in a single swoop, making them highly efficient at catching krill.

This is important as whales of this size expend a lot of energy just existing, so they need to make the most of every mouthful and get the most bang for their buck.

As krill is so abundant in Antarctica during the summer, baleen whales can maximize the amount of krill they get and take in 500 kilograms of krill in a single mouthful.

This equates to around 457,000 calories, meaning the whale gets around 200 times the amount of calories back that it expended in the attempt.

As you can see, this fishing method is highly effective for baleen whales and allows them to pack on the weight they need to survive. You could say that whales are BULKING during feeding season.

Which Whales Eat The Most Krill?

Krill is an excellent food source for all baleen whales. It’s easy to catch, abundant in supply, and packed full of calories.

But there are some whales that eat WAY more than any other whale species:

Blue Whale

The blue whale has one of the largest appetites on planet earth and eats up to four tonnes of krill every single day!

The majestic giants have a size equivalent to 25 elephants, 300 polar bears or 15 school buses and therefore have an appetite to match.

To sustain such an animal, these whales need to eat TONNES of krill to ensure they’ve got the energy to move around.

Shifting all of that weight is no small task, even for the biggest animal on earth!

Humpback Whales

Humpback whales are also giant animals and can eat anywhere from 5 to 30 percent of their body weight in krill every day.

Whilst not as giant as the blue whale, they travel much further during migrations and therefore are required to eat as much krill as possible to fuel their journeys.

The average-sized adult humpback whale eats around 4,400 – 5,500 pounds of krill, plankton, and small fish every day during feeding season.

They eat twice a day to stock up on as many calories as possible to gain the weight they need to travel.

Right whales, minke whales, fin, and sei whales also eat A LOT of krill every day during feeding season as they too have baleen plates.

But these whales often include other sea creatures in their diets such as crustaceans, squid, and small fish.

What Happens When Whales Eat Krill?

Krill are small shrimp-like animals that contain a large amount of iron – a nutrient that is hard to come by in the ocean.

When whales eat krill, they convert the protein into blubber and defecate iron-rich waste, helping them increase their body weight significantly over a short duration.

humpback whale
Image: Gregory Smith via Flickr

Whales survive by eating krill because they eat SO MUCH of it. In summer, krill is so abundant in Antarctica that whales travel thousands of miles to reach the rich waters.

Over a four to five-month period, many species of whale travel to Antarctica to benefit from the krill-rich waters.

There’s enough for everyone to get their fill.

Final Thoughts

Hopefully, you now have a clear answer to your question of “do whales eat krill” and why they do so.

It seems strange that the largest animals on earth can survive from some of the smallest, but thanks to special baleen plates it makes eating so much easy for these whales.

One mouthful from a baleen whale can scoop up thousands of krill, providing them with a nutrient-rich meal that can sustain them and help store fat for the winter months.

The amount of krill baleen whales eat during feeding season is nothing short of mind-boggling, but krill is a staple in many whales’ diets that they LOVE to eat.

Thanks for taking the time to learn about whales today and I’ll catch you in the next one!

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