Have you ever heard of Blue Glaucus? They are really weird animals. Their scientific name is Glaucus atlanticus. They are commonly known as sea swallow, blue dragon, blue sea slug and blue ocean slug etc. Actually they are a species of small-sized blue sea slugs. A pelagic aeolid nudibranch, a marine gastropod mollusk in the family Glaucidae. This is the only species in the genus Glaucus, but is closely related to Glaucilla marginata, which sometimes is included in Glaucus.
The normal size of this species is up to 3 cm. It is silvery grey on its dorsal side and dark and pale blue ventrally. It has dark blue stripes along the edge of its foot. It has a tapering body which is flattened and has six appendages which branch out into rayed cerata. Its radular teeth bear serrated teeth on their blades.
Glaucus is a hermaphrodite, containing both male and female reproductive organs. Unlike most nudibranchs, which mate with their right sides facing, sea swallows mate with ventral sides facing. After mating, both animals produce egg strings.
Blue glaucus is usually the blue ocean slug for good reason. The vibrant blue color is one of the most visually striking features of the animal. This feature was not only the evolutionary selected because of its appearance, but also provides protection against potential animal predators such as birds fly above the waters it inhabits.Blue Glaucus has a perfect example of a counter-shading. The belly, which floats on the sea surface, the blue and white color that matches the color of the ocean, while the dorsal side, which is down to the water’s silver-gray to protect against predators.
Though the camouflage is one method of the Blue glaucus is defending itself in dangerous open water, another method is that it can defend their prey to steal and use for his own protection as mentioned earlier. Like most aeolids, they do this by taking the nematocysts and stored in special bags that are called cnidosacs, transfer them to the ends of their limbs-like excrescences called “cerata”. A study using microscopy that the nematocysts in Blue glaucus same nematocysts were found in P. physalis prove that the sea swallow does in fact these nematocysts obtained from other organisms.
Another intriguing fact is that the Blue glaucus is hermaphroditic and oviparous. In reality, most sea snails snails are hermaphrodites which both strings of egg production after mating has taken place. The Blue glaucus tends to deposit eggs on driftwood or even the skeletons of their prey. They lay their eggs on floating objects or animals to keep their young until they develop so that their lungs. Blue glaucus has an interesting part of male reproductive organs. The male organ is large and hooked, probably to get around the cerata dangerous that could present problems when couples where animals are forced to be close to each other.