Butterflies of the Sea: Flamboyantly Decorated Marine Animals

These marine animals are considered as one of the ocean’s most beautiful creatures as they are flamboyantly decorated with extremely striking and brilliant color. They are grouped to the Class Gastropoda and belong to the Order Nudibranchia, in the Phylum Mollusca (molluscs or soft-bodied animals which include squids, octopi, abalones, shells, scallops, oysters, mussels, Chitons, and etc.). They are also known as Nudibranchs which means “naked gill” in Latin as they carry their exposed plume-like external gills on their backs. Unlike the snails, they do not have shell to cover their soft bodies from injuries and scratches. Despite the absence of the hard shells, they use a defend strategy called cryptic coloration or in a simple word “camouflage” to protect themselves.

Scientists believed that Nudibranchs are naked gill molluscs whose ancestors shrugged off their shells millions of years ago and thus Nudibranchs crawl through their lives as slick and naked creature when they are born. Approximately 3,000 species of these marine molluscs are found living particularly from shallow reefs to two miles beneath the sea floors all over the world. The species from the Family Chromodorididae alone are found to be more than 360 species distributed around the oceans of Caribbean, Mediterranean and Indo-Pacific. There are about 350 species of them being identified from the Great Barrier Reef.

Divers may come across these marine animals with their skins, muscles and organs sliding on trails of slime onto the sandy shallows and reefs to the ocean beds and coral heads. Some of them may be seen thriving in warm and cold waters but some even be seen billowing around deep-sea vents.

Though these naked sea slugs have a relatively large arsenal, their sizes are roughly of a human’s index finger. Their average sizes can reach to about 50mm. That is why they always become a quick snack and an easy digested food for turtles, sea stars, humans, and even marine organisms. No matter how beautiful and dazzling coloration of their bodies, they live no longer than a year.

In contrast to their beauty, they are born blind as their tiny eyes discerning little more than light and dark. Despite of the blindness, they use their head-mounted sensory appendages called rhinophores and oral tentacles to smell, taste, and feel their world. Their chemical signals assist them to detect food sources like barnacles, small fish, eggs, and other tiny marine organisms. The adaptation of their brightly colored bodies is signals to warn their predators that they are tasteless or even deadly for them to feed on. Some may even have toxic glands just below the surface of their mantles to defend themselves from enemies. However, some species are able to swim swiftly and vigorously when disturbed.