linneus longissimusYou may think that the longest animal in the world is the blue whale with its incredible 33 meters long. Maybe you can think on the Lion’s Mane Jellyfish, with its amazing 36 meters long tentacles. Or, if you include creatures from the past, you could think on some diplodocus  like dinosaur, with no less than 60 meters from head to tail. But actually the longest living creature in the world is a simple and fragile worm.

The Bootlace Worm (Lineus Longissimus) its a worm from the family of nemertean. All of them are identifiable by the harpoon like tentacle they have near the mouth and which they use to sting or trap little preys to feed. These creatures are common in Britannic coasts. They can be found in sandy or muddy beaches, or ever hidden between rocks or corals. 

They are only 1 cm thick, but despite this, they easily reach 30 meters long. Some specimens of 55 meters have been founded. More than this, their bodies are so flexible that it has been calculated that stretched it could overcome the 60 meters long.

But despite this amazing size, this creature is inoffensive and really fragile. Its only defense is a kind of mucus of pungent and disagreeable smell.

Why a creature reaches such size? Size is always an advantage against predators. Also, when you combine a simple and sedentary way of life (like just sit and wait for preys) with a big lifespan, you can get creatures like this. But all these are just suppositions, the real reason for this worm to be like this, is a mystery.