Antarctic Giant Isopod, Glyptonotus antarcticus

Image: Martin Rauschert

I find this critter looks incredibly grim, with those massive, spiky, macabre limbs of his. They look like some kind of mythical beast that might climb out of the crater of an active volcano. There's something very "brimstone" about them.

Instead, they are found in the freezing cold waters of the Antarctic, mostly near the coasts. So I guess I was about as wrong as I could be with the volcano thing.

Looking for information on this Giant Isopod I see that some say it reaches about 9 cm (3.5 in) long, while others insist it's just over twice that. Bit odd. Either way, it's definitely big, but not as big as our classic Giant Isopod. Also, while those fellows were from the deep sea, Glyptonotus antarcticus lives from the intertidal zone down to a depth of about 600 metres (1,970 feet). So they can definitely go deep, but they also go right to the surface for a frolic in the Sun. I guess you can do that when the water is horribly cold from top to bottom. And, of course, you like to be horribly cold.

Image: Martin Rauschert

Another difference is that while the other Giant Isopods look like gigantic Woodlice/Roly-polies, this one is a little different. It's those huge, barbarous legs! Antarctic Giant Isopods have 3 pairs of normal, little legs and 4 pairs of great, big, spiky ones.

Apparently, when threatened they raise a couple of those legs into the air. It's like someone held a gun to them and said "stick 'em up!" A look at those ghastly limbs and our highwayman may well change his mind and be on his way.

He'd better keep his wits about him, because the Antarctic Giant Isopod can also swim. Upside down, as it happens. It's an extraordinary sight, if not a particularly nice one. And the idea of those legs being liberated from the floor is not exactly welcome, but I don't suppose it has anything to do with me. If I ever move to the Antarctic, though, they better be prepared for my "Not In My Back Yard" placards.

I now have an image in my head of an Antarctic Giant Isopod holding aloft 4 tiny placards.