Tunnel snakes were a life form indigenous to Pern.
After Landing, first year
Tunnel snakes are a native animal to Pern. Some of them are eatable, but when Porrig Connell leader trapped, skinned, and grilled some, he took one bite and had to wash out his mouth because it started to swell. He gave the order to his people to kill them. They wanted dogs to go down the holes to get them. After Sean Connell impressed his two browns, he was put to watching the babies, after a blue molted tunnel snake took a bite out of them.
First Interval - Second Pass
Second Interval - Third Pass
Eight Interval - Ninth Pass
K'van earned marks by catching tunnel snakes, and Pell would boast that they are good eating. He caught many in Igen Caverns and in the woods in Lemos Hold; they were used by many folks while traveling.