8 Largest Giants of the Deep

Giant octopus attacking ship

The deep, dark ocean is a scary place, and it’s teeming with creatures that can inspire many a horror flick. Here’s our round-up of real-life monsters, animals that exhibit what’s known as abyssal gigantism, or the tendency for deep-sea dwellers to be much, much larger than their shallow-water cousins. It’s not known exactly why this type of gigantism occurs, but one thing’s for sure, we’re lucky that a close encounter with any of these eight giants in their natural habitat is rare!

Image: Hans Hillewaer via WikiMedia Commons

The Japanese spider crab can be found skulking around the bottom of the deep, dark sea floor. It can weigh up to 44 pounds, possess a leg span of almost four metres and boast a body size of 15 inches. It’s also incredibly long-lived, with a lifespan of up to 100 years.

Image: coda on flickr

It’s a pill bug on steroids! The giant isopod is a scavenger that thrives in deep, cold waters. At up to 14.5 inches in length and up to three pounds in weight, this creepy crustacean is a meaty dish that’s sometimes boiled and served in Northern Taiwanese oceanside restaurants.


Image: C. Van Dover, OAR/National Undersea Research Program (NURP); College of William & Mary via WikiMedia Commons

If the thought of accidentally crushing an earthworm on a rainy day makes you cringe, you don’t want to know about the hordes of giant tube worms that live miles deep under the sea. These animals can grow to more than two metres long, and love the extreme heat and sulfurous environment near hydrothermal vents called ‘black smokers’.

Image: Steve O’Shea/New Zealand National Institute of Water and Atmospheric Research via WikiMedia Commons


According to all known records, this 75 kg, four metre-long beast is the largest octopus on our planet, though some say the North Pacific Giant Octopus can grow even larger. Male octopuses have a specialized egg fertilization arm that’s coiled-up by the right eye, making it look like the octopus only has seven arms.

Image: NOAA/R. N. Lea via WikiMedia Commons

Although the title of ‘world’s largest octopus’ is disputed, there’s no mistaking that the North Pacific giant octopus is a formidable killer. Watch this video and you’ll see that even sharks aren’t safe in its company.


At up to 11 metres, the king of herrings is cited in the Guinness Book of World Records as being the longest fish alive. But even though it can grow to be quite large, it is very elusive; it wasn’t until 2001 that it was filmed alive.

7. Bigfin Squid

We’ll focus on two of the many monstrous squid species here, including the alien-like bigfin squid. This squid’s got huge fins that resemble dumbo-ears as well as extremely long arms and incredibly elastic tentacles that are held at strange angles to it’s body. Check out this eerie video.