This week we travel to North America and learn about one of the largest amphibians in the world, the Hellbender. Amphibians are incredible animals that have adapted and survived for hundreds of millions of years. Sadly, amphibians are one of the most endangered class of animals on the planet. It is estimated up to 41% of all amphibian species are threatened with extinction. Being one of the largest, Hellbenders and the other giant salamanders of the world are also threatened with extinction. These are incredible and ancient animals that you need to know about.
Amphibians are some of the oldest evolved animals on the planet. They first made an appearance over 330 million years ago. This was even before reptiles emerged and around the time animals were establishing a terrestrial existence. Over time amphibians diversified, to include giant salamanders. The first giant salamander first emerged around 170 million years ago and today is represented by three species:
There are two species of Hellbenders:
- The Ozark hellbender (Cryptobranchus alleganiensis bishopi) lives in a small number of rivers in Missouri and Arkansas
- The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) is broadly distributed throughout the Appalachian region (southern New York to northern Georgia) and also occurs in Kentucky, Ohio, Indiana, Illinois, and Missouri
Hellbenders are the smaller of the three species of giant salamanders but still large. They can reach up to 29 inches (74 cm) in length and weigh up to 5 lbs. (2.2 kg). Of the three, the Chinese Giant Salamander is the largest and can reach up to 6 feet (1.8 m). These animals have long bodies, flat heads, and a paddle like tail. Hellbenders have “frills” along the sides of their body. Hellbenders do not breath through gills, or even lungs much, like other amphibians. Rather, they breath through their skin. These are primarily aquatic animals and absorb oxygen through their skin. A major study published in 1973 discusses this and is HERE
Other Hellbender facts include:
- Live up to around 25 years in the wild, maybe up to 50
- Nocturnal, hiding by day and hunting by night
- Primarily eat crayfish (90%) of diet, but may eat insects, small fish, and even small Hellbenders
- Have two small eyes but not great eye sight
- Have light-sensitive cells along body, aiding them in hiding during the day
- Great sense of smell helping them to hunt
- Solitary animals
- Mate by external fertilization
Overall, Hellbenders are classified as Near Threatened by the IUCN. However, the Ozark Hellbender is considered to be Endangered with less than 600 left in the wild. They have received protection under the United States Endangered Species Act. The Chinese Giant Salamander is considered Critically Endangered with an unknown small population. The Japanese Giant Salamander is also considered Near Threatened. All of these species have lost habitat due to human interference. Most importantly, these animals require clean water to live and pollution and human exploitation have devastated their habitat.