May 6th – 12th 2013
Well did you guess what this week’s creature was? For those of you who had it just on the tips of your tongue … let me put you out of your misery… its a Blue Sea Slug, also known as a sea swallow or a sea dragon!
Blue sea slugs float on their backs on the top of the sea, so the beautiful blue colours we see are actually the underside (foot) of the creature. Their backs, submerged in the water, are actually a silvery-grey colour. They are able to float due to a large sac in their stomach which they fill with air.It’s official name is a Glaucus atlanticus and it is a nudibranch (a shell less* mollusck). These little creatures usually only reach about three to four cm in size but don’t let that fool you…. they have a mean sting! The blue sea slug preys on larger toxic sea dwellers such as the Portuguese Man O’ War (Physalia physalis). It is immune to the stinging cells (nematocytes) within these creatures and is also capable of storing these deadly toxins within its own body and using them for its own defense. The more venom it accumulates the deadlier its sting!
*Nudibranches may have shells during early stages of development but are shell less when fully mature).