11 Intriguing Transparent Animals

Glass Shrimp

Also known as ghost shrimp, these minuscule crustaceans have nearly translucent shells. In the wild, different species can be found in ponds, lakes, and streams in the eastern U.S. from Florida to New Jersey. The animal is so clear in appearance that it only has color during reproduction or after it has eaten a colorful meal—which is typically plant-based, so it's usually green. Amazingly, it can survive six days without oxygen.

Glass Frogs

There are over 100 species of amphibians of the family Centrolenidae, or glass frogs. The abdominal skin of many of these animals is highly transparent and their internal organs are on display. Most range in color from light to dark green. Found in the jungles of Central and South America, these animals are mostly arboreal and tend to live high in the trees over water. They have powerful legs that allow them to leap 10 feet in a single jump.

Glasswing Butterfly

If it wasn't for the opaque outline around the glasswing butterfly’s transparent wings, the average observer might not see one perched on a leaf or flower. This unusual feature allows the glasswing to remain camouflaged even in flight. Found throughout Central America and parts of South America, adult glasswing butterflies will often migrate great distances. Males of the species are known to lek, or gather in large groups for the purpose of competitive mating displays. They may look fragile, but these butterflies can carry up to 40 times their weight.

Barreleye

This unusual fish is found in the deep ocean. Sometimes called a "spook fish," no doubt because of its appearance, the barreleye has a completely transparent forehead. In 2009, researchers at the Monterey Bay Aquarium Research Institute made several surprising discoveries about the barreleye. While it was previously believed that the fish had a fixed gaze that only allowed it to look straight up, researchers discovered that the eyes of the barreleye can rotate and are actually located within its clear head. They also concluded that because of this unique adaptation, the barreleye can look in multiple directions, including straight up as it swims, allowing it to detect the silhouettes of available prey.

Because the scientists were able to study barreleye fish in their environment using ROVs (remotely operated vehicles), they also discovered that these deep-sea creatures are able to remain almost motionless in water thanks to their large flat fins. This is another adaptation that gives barreleyes an advantage over their prey.

Glass Octopus

The glass octopus is so unique that it occupies its own family, Vitreledonellidae. Little is known about this marine animal, but it can be found in tropical and subtropical waters around the world. Thanks to its transparent skin, which it likely evolved to better escape predators, scientists know that its optic lobes have unusually long optic nerve stalks, meaning its sense of sight is acute. Your eyesight would have to be pretty good, too, to spot one of these ghostly creatures.

Crocodile Icefish

These Antarctic predators are unusual because their transparent appearance is due in large part to their nearly invisible blood. They are the only known vertebrates in the world that are white-blooded and do not have hemoglobin, the protein in blood that transports oxygen. They survive without hemoglobin thanks to the subzero temperatures of the ocean where they live, since cold water has a much higher level of dissolved oxygen than warmer water. Their larger hearts and gill blood vessels help to move a higher volume of blood and to extract sufficient oxygen for survival. Their unique adaptation lowers their internal body temperature so they can survive in the extreme cold of the Southern Ocean.

Tortoise Shell Beetle

This remarkable beetle is not completely transparent, but it does have a carapace that is nearly invisible. The purpose of the transparent outer shell is to fool potential predators, as it reveals markings on its back that act as a warning. Tortoise beetles come in many different varieties, and the design under their clear shells can be distinct and beautiful.

Salps

Not to be confused with jellyfish, salps (aka sea squirts) are transparent, free-floating tunicates. Their gelatinous bodies swim by contracting and pumping water through internal feeding filters, feasting on algae while they move. They are thought to be the fastest-growing multicellular creature on Earth, increasing their body size by 10% every hour. They can be found anywhere but are most common in the Southern Ocean, where they sometimes form enormous transparent swarms. During the day, salps can be seen feeding at the water’s surface, while at night they make their way to the bottom of the ocean to avoid predators.

Transparent Sea Cucumber

Discovered by researchers with the Census of Marine Life, this sea cucumber is so transparent that its digestive tract is on spectacular display. Found in the Gulf of Mexico at a depth of 2,750 meters (over 9,000 feet), it is one of many unusual finds discovered by the marine census, which was conducted over a 10-year period ending in 2010. When encountered, this cucumber was creeping forward on its many tentacles at about two centimeters per minute, sweeping detritus-rich sediment into its mouth.

Glass Squid

There are about 60 different species of glass squid, named as such because many of them appear completely transparent. This transparency keeps them hidden from predators by allowing them to blend into their surroundings; this is particularly important in the deep ocean in which they thrive. One species, the cockatoo squid, has other adaptations as well: it can change from transparent to colored when threatened, and is able to expand in size and hold itself motionless when necessary.

Jellyfish

Perhaps the most well-known transparent creatures are jellyfish. Many of the free-swimming members of the phylum Cnidaria are transparent, a trait that makes them occasionally hazardous because of their sometimes deadly stings that can surprise swimmers who don't see them coming. They are also some of the most ancient creatures on Earth and their translucent bodies make them among the most elegant and beautiful of the ocean's creatures.