Blue Glaucus Unique Coloration Is Nature’s Camouflage [Video]

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Blue Glaucus
Courtesy of Vasil (Wikimedia CC0)

The Blue Glaucus is a sea slug with interesting characteristics. It grows to about three centimeters long, and it can weigh anywhere from three to 100 grams The sea slug is not venomous but can be deadly even after it is dead.

The creature eats an array of prey but its favorite is the Portuguese Man o’ War. The Blue Glaucus takes on the toxins of the prey it consumes, therefore, it can use that venom to kill other prey or use against predators. It can be found in all oceans. It should not be touched if found. Symptoms of a venomous sting include nausea, vomiting, and physical pain.

Blue Glaucus
Courtesy of lostandcold (Flickr CC0)

The Blue Glaucus has a distinctive blue and grey coloring that allows it to reflect the ocean and the sky to protect it from predators while it lazily floats on the ocean’s surface. Its coloring is called “countershading.” The back of the creature is a silvery grey. Its stomach is dark and pale blue and the head has stripes of blue. This shading protects the Blue Glaucus from predators above and below the surface of the ocean.

It has a flat, tapered body with six appendages that branch out into 84 finger-like cerata. “Cerata are long, slender structures used to sting when hunting or when the Blue Glaucus feels threatened,” according to American Oceans. The teeth have a serrated edge and it has a “rasp-like tongue.” The sea slug moves slowly by swimming or it can move with muscle contractions or the millions of hairs on its underbelly.

The Blue Glaucus is a hermaphrodite, it produces both sperm and eggs, however, it needs to mate to lay eggs in the carcasses of its prey or in any floating mass they come across. They release a string of 10-20 eggs. When mating, the creatures must be careful not to sting each other.

They are considered pelagic fish. The sea snail lives in ocean waters that are neither close to shore nor near the ocean floor. The Blue Glaucus can be found in oceans around the world. They enjoy floating on the surface of the water. They have a gas-filled sac to store air bubbles in to maintain buoyancy. Sometimes they will float to the sand on the floor of the ocean. They allow the wind and the current to carry them and sometimes they end up in places they should not be such as the shore. This incidence has occurred more frequently in recent years.

Written by Jeanette Vietti


American Oceans: Blue Glaucus
Oceana: Blue Glaucus
YouTube: Facts: The Blue Dragon

Featured Image by Vasil Courtesy of Wikimedia Commons – Creative Commons License
Inline Image Courtesy of lostandcold’s Flickr Page – Creative Commons License

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