Bathynomus Giganteus: Terrifying Sea Beast Hauled Up

By Jeremy A. Kaplan (

A submarine exploring the ocean’s depths recently returned with an unexpected visitor: a crablike critter called Bathynomus giganteus (commonly known as giant isopod) that has left many readers startled and horrified.

giant_isopod_(Bathynomus-giganteus) photo.jpg

This giant isopod (a crustacean related to shrimps and crabs) represents one of about nine species of large isopods in the genus Bathynomus. They are thought to be abundant in cold, deep waters of the Atlantic and Pacific oceans.

Photo of Bathynomus giganteus courtesy of NOAA Vents Program

In a posting to social bookmarking site Reddit, a deep-sea technician detailed finding the Bathynomus giganteus, asking the site’s readers to help identify what exactly the bizarre-looking creature was.

The post reads, “I work for a Sub-sea Survey Company, recently this beast came up attached to one of our ROVs. It measures a wee bit over 2.5 feet head to tail, and we expect it latched onto the ROV at roughly 8,500 feet depth.

“Unfortunately, the e-mail that these pictures were attached to came from a contractor, and the ship he was operating from (and therefore location) is unknown, so I can’t tell you what part of the Earth this beast was living.”

The pictures reveal Bathynomus giganteus to be a giant isopod, a large crustacean that dwells in deep Atlantic and Pacific waters. This particular creature is a deep-sea scavenger that feeds on dead whales, fish and squid.


The underside of a male giant isopod.

Photo courtesy of NOAA/OER.

Scientists have long remarked on the massive scale of Bathynomus giganteus.

C.R. McClain, writing about Bathynomus giganteus on ScienceBlogs, explained one theory for the size, that “deep-sea gigantism, for all crustaceans, is a consequence of larger cells sizes obtained under cold temperatures,” citing a research paper from 1996.

He also speculated that “in crustaceans, bathymetric gigantism may also in part reflect decreases in temperature leading to longer lifespans and thus larger sizes in indeterminate growers.”

Bathynomus Giganteus Post Inspires Curiosity, Horror

Responses to the original post ranged from the curious to the horrified.

One reader notes the connection between Bathynomus giganteus and a more familiar household pest: “The giant isopod is related to the “woodlouse”–turns out this is the common bug that I grew up calling a “roly poly”

or pillbug. Neat!”

Others were more disgusted with Bathynomus giganteus. “I remember watching some documentary (Blue Planet maybe?) with a time lapse of these things swarming a whale carcass. it was horrifying,” writes one


Another reader saw nothing but dinner in the flesh of Bathynomus giganteus, writing “It could be because I really like seafood, but those isopods look tasty. Land bugs = ew! Sea bugs = mm mmm good.”

Jeremy A. Kaplan is science and technology editor at A “frequent author and a technology nut,” Jeremy worked previously at Ziff Davis Media, where he was executive editor of PC Magazine, launched several magazines, and co-hosted the Fastest Geek competition. He founded the GoodCleanTech blog, which was nominated for a 2007 Weblog award, a MIN Best of the Web award, and a finalist for a Jesse H. Neal National Business Journalism Award.

Read more of Jeremy’s work on FOXNews/SciTech.


  1. BrizeeGyrl
    United States
    August 4, 2014, 10:35 pm

    They are Marine Wood Louse … relayed to the Roly poly!
    They’re delicious … sweeter than Lobster. My Husband is from Turks and Caicos , that’s the forest time that I had ever seen them and tasted them.

  2. frijolitoa
    April 7, 2010, 12:26 pm

    I can’t believe that someone found that.
    I feel both terrified and freaked out at the same time of how it looks.

  3. QBP Daniel
    April 7, 2010, 12:08 pm

    Simplemente asombroso. Y lo que nos falta por descubrir. Thanx NG.

  4. DHunton
    April 5, 2010, 8:38 pm

    That picture is, as credited, courtesy of NOAA. The picture of the one just pulled up recently is linked from here:
    The first post has links to pictures of the “front” and “side” of it.

  5. Kelleth
    April 5, 2010, 6:53 pm

    I could have bought one of these preserved in a jar of alcohol.
    But it was rather expensive and heavy.(plus my girlfriend didn`t like it lol) I for one am more curious the terrified this is one of the wonders of nature a beautiful example of evolution in the works.

  6. jadterp
    April 5, 2010, 5:14 pm

    Does anyone know if they’ve found any living relatives to the extinct trilobites?

  7. Taras
    April 4, 2010, 7:32 am

    Creepy, but, uh, the photos were taken eight years ago:

  8. AKLorgus
    April 1, 2010, 4:19 pm

    Thats not a Rolly Polly pill bug, thats an underwater cockroach 🙁 Yech!!

  9. bw
    April 1, 2010, 3:32 pm

    That is the biggest roly poly pill bug I have ever seen.