Animal of the Month
April 2022

Name: Blue Sea Dragon (A.K.A. Blue Angel, Blue Glaucus, Dragon Slug, Blue Dragon)

Class: Gastropoda
Order: Nudibranchia
Suborder: Cladobranchia
Family: Glaucidae
Subfamily: Scarabaeinae
Genus: Glaucus
Species: G. atlanticus

Size: 1.2 inches long.
Weight: N/A

Small, round head; long body with three sets of wing-like fins, each with many cerata or finger-like appendages.
Color(s): Silvery topside, blue and white underside.
Behavior: Floats with ocean currents, sometimes bands together in groups.
Preferred Habitit: Open ocean.
Range: Tropical and temperate waters throughout the world.
Diet: Larger venomous, pelagic organisms, including Portuguese man o'war.
Lifespan: Up to a year.

Status: Not Evaluated

Ever heard of the phrase, "pick on someone your own size?" The blue sea dragon may not have heard that one, as its prey is often several times larger than itself! Blue sea dragons, also known as blue glaucuses, blue angels, dragon slugs, and blue swallows, are gorgeous sea slugs. They have been found floating in the open ocean throughout the world.

Most photos online show the blue sea dragon in incredible detail. Don't be fooled, these ocean-dwelling critters usually only grow to about 1.2 inches long! They spend their lives floating upside-down on the surface of the ocean, with their beautiful blue and white bellies facing the sky, and their silvery-white backs facing the seafloor. This lets them blend in with the water, making it harder for predators to find them. Blue sea dragons keep afloat by swallowing air. They mostly let the currents carry them, though they are able to swim a bit with their finger-like appendages called cerata. Mostly they keep to the open ocean, though sometimes they get washed up on beaches.

Blue sea dragons have a most unusual diet. They prefer to eat animals that are larger than they are, most of which are venomous like the Portuguese man o'war. As they eat, they store their prey's venomous cells or nematocysts. This allows them to deliver their own powerful sting of venom to predators and prey! Because they concentrate their stored venom, blue sea dragons are capable of delivering stronger stings than the Portuguese man o'war, making them dangerous to handle. If you see one, DO NOT TOUCH IT! Be sure to admire it from a distance!

Blue sea dragons usually live for no longer than a year. They are hermaphrodites, meaning they have body parts that are both male and female. Even so, they are unable to reproduce without finding a mate. Blue sea dragons will find a partner, and after mating both will produce a string of eggs.

Blue sea dragons are not currently evaluated by the IUCN. There is much we don't know about their population. However, it is safe to say that they do face stress from rising water temperatures and ocean acidity, both of which are due to human-driven climate change. They also face threats from pollution. Fortunately, they appear to be a hardy species and continue to be found across the world.

To learn more about these fascinating creatures, check out these links below:

Oceana, Blue Glaucus Page-Check out these awesome facts from Oceana, one of the world's leading ocean conservation organizations! https://oceana.org/marine-life/blue-glaucus/

YouTube, "The Real Life Sea Dragon"-See blue sea dragons alive, in the water, being their awesome weird selves!


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