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11 Freaky Facts About Bathynomus Giganteus, The World's Largest Isopod

Updated June 3, 2020 99.4k views11 items

In the deepest depths of the ocean, there lives a mysterious creature that looks like an enormous woodlouse. This is Bathynomus giganteus, the largest isopod in the world. Known colloquially as the giant isopod, these monstrous arthropods make their home in one of the most isolated and desolate environments on Earth. They inhabit every corner of the globe, always scuttling across the seafloor and waiting for their next meal. Some people might think they almost look cute, but don't be fooled. Bathynomus giganteus is terrifying. 

These freaky isopods may look like their roly poly cousins, but they are much more than just big woodlice. They are excellent scavengers, ferocious predators, and spectacular survivors. They have to be, if they want to survive the harsh reality of deep sea living. While they may make your skin crawl, these amazing and sometimes frightening facts will leave you with a newfound resepct for these giant ocean isopods.

  • Even Sharks Are No Match For Them

    Video: YouTube

    This video truly serves as a testament to the hunting ability of Bathynomus giganteus, and is a stark warning for anyone who wants to mess with one in the wild. In the video, an unsuspecting shark is snagged by an overly confident isopod, but the gamble pays off. The shark bucks and thrashes to try and remove the isopod, but further accounts show that the shark does not survive the encounter. The poor shark is eventually swarmed and consumed by numerous isopods.

  • They Can Survive For Years Without Food

    While giant isopods will rarely pass up an opportunity for a meal, they can be quite content in the face of total famine. They have to be if they want to survive, as whale carcasses don't sink to the ocean depths everyday. Isopods in aquariums have been observed to go four years without a single meal.

    This tolerance to starvation is an ingenious survival mechanism for these creatures. They manage by using very little energy in their day-to-day lives, sitting still in a sort of semi-hibernation that only ends when it's time to feed or mate. While they are mostly inert, they go absolutely mad around food and will gorge themselves until they are too fat to move.

  • When Threatened, They Roll Into A Protective Ball

    Like their roly poly cousins, giant marine isopods are covered in chitinous plates of segmented armor. This is a fantastic defense mechanism that protects everything but their tender underside. Even when they're on their backs, not all hope is lost. When faced with a potential predator, these isopods have the ability to roll themselves into a ball that is nearly impenetrable to most predators.

  • Scientists Don't Know How They Get So Big

    The mechanism behind the gargantuan size of these deep sea monsters has left scientists scratching their heads for years. The truth is that we just don't know exactly how a creature can grow so large in such a nutrient-depleted environment, but isopod researchers have some interesting ideas

    One explanation for bathymetric gigantism, the phenomenon of deep sea creatures being much larger than their shallow shore relatives, is about temperature. The ocean floor is cold, much colder than the surface. It is believed that this decreased temperature makes the cells of these isopods expand, leading to an overall greater size. The cold may also slow down cell decay, leading to longer lives. Prolonged lifespans in a creature that never stops growing can lead to some impressively large specimens. It might also be possible that their large size is an adaptation to deal with immense pressure at the bottom of the ocean.