10 of the largest living creatures in the sea

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Spider crab
credit: Wikimedia Commons

Meet the incredible creatures that have inspired legends of sea monsters throughout the ages.

The largest living things in the world call the sea their home, and in fact, the largest creature to have ever lived on the planet currently resides in the ocean now. Many of these giant creatures have been at the heart of sea monster lore over the ages – and while they are not actually monsters, they are tremendous in size and some remain elusive and wildly mysterious. That's what happens when you live in a place as unexplored as the ocean is. We currently know of 228,450 marine species worldwide – there is up to 2 million more multi-celled marine organisms that remain unknown.

While the ocean's leviathans get a lot of scientific attention, there is no shortage of lore still in the works in popular culture, especially when it comes to size. To set the record straight, a group of researchers embarked on a comprehensive survey of past studies and verifiable documentation to get accurate measures for the largest known marine species. Here's what they found.

10. Japanese Spider Crab | Leg span: 12.14 feet (3.7 m)

At over 12 feet in width the Japanese spider crab has nothing on the 120-foot giant who is the longest in the sea (see page 10) ... but this is a crab. It is an arthropod, it is from the same phylum that includes crustaceans, spiders and insects. And it is not only the largest crab or crustacean in the family, but it also holds the title for the largest arthropod of all. Given that there are some 5 to 10 million species of arthropods on the planet, being king of the realm is pretty impressive.

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