National Reptile Day: A List of the World's Strangest Reptiles

It's 21 October, which means it's International Reptile Awareness day—an occasion to promote education and conservation of these cold-blooded creatures.

Reptiles are a group of vertebrates with skin made of scales or body plates (or a combination of the two) that they frequently shed. They are cold-blooded, which means their internal body temperature and metabolism rely entirely on the temperature of their surroundings.

The earliest reptiles in the fossil record are more than 300 million years old. Today, there are more than 10,000 species that have been added to the Reptile Database—including crocodiles, alligators, snakes, lizards, turtles and tortoises.

To mark the occasion, we have rounded up some of the strangest.

Mary river turtle (Elusor macrurus)

Mary River Turtle
The Mary River Turtle Chris Van Wyk/ZSL

The 'punk rock' turtle's green mohawk is actually made of algae, but it's not the only strange thing about this reptile. The Mary river turtle can breathe underwater using specialized glands in its genitals. According to experts at EDGE of Existence, a program led by the Zoological Society of London, it separated from all other living species approximately 40 million years ago. Today, it can be found in Queensland, Australia, and is listed as endangered.

Gharial (Gavialis gangeticus)

Indian gharial crocodile
Indian gharial crocodile MICHAL CIZEK/AFP/Getty

This critically endangered crocodile takes its name from the 'ghara,' a type of earthenware pot similar in shape to the bulb at the end of the males' snouts. It can be found bathing in the large rivers of India and Nepal, only leaving the water when it is time to breed or bask, the World Wildlife Fund (WWF) reports.

Green green-blooded skink (Prasinohaema virens)

Prasinohaema prehensicauda
The green-blooded skink Chris Austin/LSU

As the name suggests, the blood of these lizards takes on a strangely green hue. The bright color is the product of high levels of a toxic green bile pigment called biliverdin—the concentration of which is 40 times higher in the lizards than what would be considered lethal for humans. A study reported on by Newsweek found it is likely this sophisticated defense mechanism evolved not once, not twice, but four times.

Mata mata turtle (Chelus fimbriata)

Mata mata turtle
Mata mata turtle iStock

The mata mata turtle, found in the shallow fresh waters and marshes of South America, has a rigid shell. The wrinkles and bumps that cover its skin act as camouflage, enabling the turtle to disguise itself as a piece of bark or a pile of water, while its strangely-shaped nose works like a snorkel. This means the turtle can breathe as it remains submerged under the water.

Madagascar blindsnake (Xenotyphlops grandidieri)

Madagascar blindsnake
Jörn Köhler/ZSL

The Madagascar blindsnake looks more like an earthworm than it does a snake. Like a worm, it uses its head to bury into the sands of Madagascar, where it forages for food. According to Edge of Existence, it is a primitive species and the only one left in its genus—a lineage of blind snakes that can be traced back more than 60 million years. It has been listed as critically endangered. Indeed, it is so rare, no Madagascar blindsnake was seen for 100 years after it was first discovered in 1905.

Pig-nosed turtle (Carettochelys insculpta)

Pig-nose turtle
Pig-nose turtle AURENT FIEVET/AFP/Getty

Also known as the fly river turtle, the pig-nosed turtle gets its name from its snout, which has a swine-like appearance. It has also a soft, leather-like shell and flippers. The turtle can be found in parts of New Guinea and Australia's Northern Territory but like many animals, it is frequently a victim of the exotic pet trade.

National Reptile Day: A List of the World's Strangest Reptiles | Tech & Science