1. Transparent Frog
Native to Venezuela, the Glass Frogs belong to the amphibian family Centrolenidae (order Anura). While the general background coloration of most glass frogs is primarily lime green, the abdominal skin of some members of this family is transparent, so that the heart, liver, and digestive tract are visible through their translucent skin. (Photo by Heidi and Hans-Jurgen Koch)
2. Transparent Head Fish
This bizarre deep-water fish called the Barreleye (Macropinna microstoma) has a transparent head and tubular eyes. It has extremely light-sensitive eyes that can rotate within his transparent, fluid-filled shield on its head, while the fish's tubular eyes, well inside the head, are capped by bright green lenses. The eyes point upward (as shown here) when the fish is looking for food overhead. They point forward when the fish is feeding. The two spots above the fish's mouth are not eyes: those are olfactory organs called nares, which are analogous to human nostrils. (Photo by MBARI)
3. Transparent Butterfly
Found in Central America, from Mexico to Panama, the Glasswing Butterfly (Greta Oto) is a brush-footed butterfly where its wings are transparent. The tissue between the veins of its wings looks like glass. (Photo by Hemmy)
4. Transparent Squid
Found on the southern hemisphere's oceans, the Glass Squid (Teuthowenia pellucida) has light organs on its eyes and possesses the ability to roll into a ball, like an aquatic hedgehog. It is prey of many deep-sea fish (eg goblin sharks) as well as whales and oceanic seabirds. (Photo by Peter Batson)
5. Transparent Zebrafish created by scientists
This see-through zebrafish was created in 2008 by scientists so they can study disease processes, including the spread of cancer. The transparent fish are allowing researchers at Children's Hospital Boston to directly view fish's internal organs and observe processes such as tumor growth in real-time in living organisms. (Photo by LS)
