• Home
  • Blogs
  • Deep Sea Dwellers: 10 Facts about The Antarctic Giant Isopod

Deep Sea Dwellers: 10 Facts about The Antarctic Giant Isopod

by Caitlyn Bishop Blogs

Two thousand feet below the surface of the Southern Ocean, in the benthic zone, dwells an ancient-looking creature with four antennae, two pairs of jaws, plates on its back, and several pairs of spiny legs. It’s an intimidating sight, but Giant Antarctic Isopods are relatively harmless animals that are far more interested in finding their next meal than anything.

Regio's: Antarctica

Two thousand feet below the surface of the Southern Ocean, in the benthic zone, dwells an ancient-looking creature with four antennae, two pairs of jaws, plates on its back, and several pairs of spiny legs. It’s an intimidating sight, but Giant Antarctic Isopods (Glyptonotus antarcticus) are relatively harmless animals that are far more interested in finding their next meal than anything.

There are many species of isopods that live throughout the world, but the isopods you’ll sail over during your Antarctica cruise in particular have evolved to live in a very particular environment. Freezing cold conditions with very little light aren’t very attractive to most deep-water species, but just perfect for these strange creatures!   

“Giant” is an overstatement

On average, the Giant Antarctic Isopod grows to 9cm (3.5in.) in length. This may not seem very large, but factors including low light levels, freezing cold water, and a lack of oxygen prevent these isopods from growing very large. Other species of isopods, including the Giant Isopod, have been known to grow up to 40 cm (16 inches) in length!

Giant Antarctic isopods almost exclusively eat carrion

Isopods are opportunistic scavengers, meaning that they’ll eat just about anything that crosses their path, no matter how long it’s been dead. Anything that makes its way down to their part of the neighborhood in the benthic zone is fair game, and makes for a reliable source of food, as long as there’s no competition. While food is available, isopods will gorge themselves to ensure they have enough to survive until their next meal. As a bottom feeder and a scavenger, you may have to wait a while until something ends up that far down in the ocean. Besides carrion, isopods have also been observed to feast on small, marine prey items such as young sponges and small fish.

Their metabolism is extremely slow

Living 600 meters (2,000 feet) down in the ocean has its drawbacks. Since food can be scarce at times this deep down, isopods rely on their impressively slow metabolism to keep them going. This means limiting their bodily movements as much as possible, and not really exerting any energy unless they encounter a meal or a predator. A slow metabolism can really come in handy when food is scarce, and isopods have been observed to go a whole eight weeks without any need for food.  

No bugs here!

Don’t let appearance fool you. Isopods may look like a common garden insect, but they belong to the extremely diverse group of organisms called ‘crustaceans’, and are more closely related to crabs, shrimp, and pill bugs than they are to any true insect.  

Antarctic giant isopods are skillful swimmers

In addition to swimming upright and straightforward like a normal sea creature, the Giant Antarctic Isopod can also swim upside down, and does so with great gusto! Scientists are unsure why they exhibit this behavior, but it is very well documented.

Antennae lead the way

To help guide them around the murky depths of the ocean, giant isopods rely on two sets of antennae. Additionally they have two large, fixed, compound eyes, much like an insect’s, to further help them find their way throughout their dark environment. These eyes, however, have been found to be more ornamental than anything, and don’t necessarily assist in the ways of vision, according to researchers. Even with these highly specialized eyes, their vision is very poor, thanks to their lightless environment.

Even with poor vision, their eyes glow

If any light happens to shine on their eyes, a part of their eye called the tapetum, which is located at the back of the retina, reflects any visible light back through the retina, creating a glowing effect. The tapetum has evolved in many different species of animals, and serves to assist with vision in low light conditions.

To deter predators, Antarctic giant isopods will roll into a ball

Just like their cousins, the pill bugs, isopods will roll up into a tight ball when faced with a predator. Only when they’re certain that the predator has moved on will they unroll. If their hard, external segments don’t protect them from predation, they can always rely on their four pairs of sharp jaws, which are meant for ripping prey apart, to help them out. Considering their size, number of jaws and overall diet, the isopod doesn’t seem like a very attractive prey item. 

…Or they warn with their legs

It can be difficult to maneuver three pairs of small legs, and four pairs of large, spiny legs. The only time having this many legs comes in handy is when a predator presents itself. In this case, the isopod will raise its legs up in the air and try to make itself appear as large and as dangerous as possible. Hopefully this display makes a potential predator rethink its decision.

Females protect the eggs

Not only do isopods have the largest eggs of any marine invertebrate at 1.3cm in length, but the female will carry them with her in a special ‘brood pouch’ until the babies are ready to hatch. To minimize threats from predators, females will bury themselves in the soft, sandy bottoms of the ocean and sit with her eggs until they are fully developed. This is a time when having a slow metabolism definitely comes in handy.  

Gerelateerde reizen

Atlantische Odyssee, excl. Antarctisch Schiereiland
Tot US$5950 korting

Atlantische Odyssee, excl. Antarctisch Schiereiland

Deze verre expeditiereis vaart over de hele Atlantische Oceaan en bezoekt een aantal van de meest afgelegen eilanden ter wereld!

HDS31-24 De Atlantic Odyssee is een waar vogelgenot, omdat we de vogeltrekroutes doorkruisen van soorten als de Noordse stern en de kleinste jager. We bezoeken enkele van de meest afgelegen eilanden in de wereld terwijl we de Atlantische Oceaan en de evenaar...

m/v Hondius

m/v Hondius

Reisdatum:

28 mrt. - 20 apr., 2024

Ligplaatsen starten vanaf:

4250 USD

Van St. Helena naar Kaapverdië
Tot US$650 korting

Van St. Helena naar Kaapverdië

Aanschouw de noordelijke voorjaarstrek

HDS32-24 Tijdens de dagen op zee is de kans op een ontmoeting met walvissen groot. Beleef de noordelijke voorjaarstrek van vogels zoals de Noordse Sterns en de kleinste jagers die samen met ons de evenaar ("de lijn") oversteken.

m/v Hondius

m/v Hondius

Reisdatum:

20 apr. - 30 apr., 2024

Ligplaatsen starten vanaf:

2150 USD

Falkland Islands – South Georgia – Antarctic Peninsula

Ontmoet wel zes soorten pinguïns!

PLA20-24 Een expeditiecruise naar de Falkland Eilanden, South Georgia en het Antarctisch Schiereiland. South Georgia wordt wel een Antarctische oase genoemd, vanwege de enorme aantallen zeevogels en zeezoogdieren die er voorkomen. Tijdens deze reis kunnen we...

m/v Plancius

m/v Plancius

Reisdatum:

18 okt. - 7 nov., 2024

Ligplaatsen starten vanaf:

13350 USD

Antarctica - Basecamp

De beste actieve reis in Antarctica

HDS21a24 Een Antarctic Peninsula Basecamp expeditiecruise biedt sportieve activiteiten om Antarctica te verkennen. De expeditie geeft u de mogelijkheid om te wandelen, om te sneeuwschoenwandelen, kajakken, bergsporten en zelfs om te kamperen onder de zuidelijke...

m/v Hondius

m/v Hondius

Reisdatum:

1 nov. - 13 nov., 2024

Ligplaatsen starten vanaf:

8800 USD

Weddell Sea – Op zoek naar de Keizerspinguïn, incl. Helikopters

Op zoek naar de bijzondere Keizerspinguïn.

OTL22-24 Een gedurfde expeditiecruise, deze reis naar het gebied van de Keizerspinguïns bij Snow Hill Island in de Weddell Sea. Er wordt tijdens deze bijzondere reis gebruik gemaakt van helikopters. Er worden vele bijzondere diersoorten verwacht tijdens deze...

m/v Ortelius

m/v Ortelius

Reisdatum:

10 nov. - 20 nov., 2024

Ligplaatsen starten vanaf:

12100 USD

Loading