Who are the Biggest Animals in the Ocean?

Whales dominate the ocean when it comes to size!

Standing on the shore, looking out into the ocean—it seems vast and never-ending!  It should come as no surprise that some of the largest animals on Earth live in the ocean. Join us as we explore the big, bigger and biggest creatures that call the ocean their home.

#5—Giant Manta Ray

Lindsey Dougherty

The giant manta ray is the world’s largest ray with a wingspan of up to 29 feet. For such a large animal, their diet consists of the tiniest of creatures—zooplankton. Giant manta rays are filter feeders and they are both graceful and gentle. Not only are giant manta rays BIG, they are also very smart, possessing the largest brain of any fish. They can make migrations across the ocean, finding their way by following topographical maps using ocean landmarks, such as seamounts.

#4—Sperm Whale


The sperm whale is the largest toothed whale in the world. Sperm whales have the largest heads, biggest brains and make the loudest sound of any animal on Earth. A sperm whale can also hold their breath for an astounding two hours at a time—hunting for prey at deep depths of up to 3 km in the ocean. Fun fact: The white whale in Moby Dick was based on two real-life sperm whales.

#3—Whale Shark


Whale sharks are the biggest fish in the world and can grow up to 40 feet long and weigh up to 20,000 pounds. That is as tall as two giraffes stacked on top of each other and the weight of two elephants combined! Whale sharks are gentle giants. They are not predatory, like other sharks—their feeding habits are more like that of a whale. Now, we have probably confused you. Is a whale shark a whale or shark? They are sharks, meaning fish, not a mammal, the classification of whales.

#2—Fin Whale


Coming in at second place—the fin whale is the second-largest species on Earth. Sometimes referred to as the ‘greyhounds of the sea,’ the fin whale can swim at astonishing speeds of up to 45 kph. And, with such large stomachs to fill—the fin whale can eat up to 2000 kg of krill every day! That’s a lot of krill.

#1—Blue Whale


Coming in at #1… the blue whale! Not only is the blue whale the largest animal to live on the Earth today, they are also the largest animal to have ever existed on Earth. A blue whale can grow up to 100 feet long and weigh upwards of 200 tons. A blue whale’s tongue alone can weigh as much as an elephant and its heart weighs as much as an automobile. What feeds such a massive marine mammal? Tiny, tiny shrimp-like animals called krill.  A blue whale can eat up to four tons of krill in a day.

The BIG rely on the small

What I find the most astonishing about this BIG ocean animals—is that they feed on the smallest creatures in the ocean. This means we have to work together to keep the entire food chain in our ocean healthy and balanced. While zooplankton, krill and copepods may not be as cute as the charismatic critters that depend on them—they are critical for all life in the ocean.

Our work is focused on solving some of the greatest threats facing our ocean today. We bring people, science and policy together to champion innovative solutions and fight for a sustainable ocean.
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