What is the purpose of the lizards in Haven?

The only purpose I could find for the salamash was for a secret achievement:

In My Shoes: Taste the hygrocybe rubescens.

This is how you earn it:

After defeating your first salamander type enemy of the game, you will name it Oink. Upon returning to the Nest, you will find that Oink followed you home. Interact with it to pet it, and continue to do so every time you return to the Nest. You'll get a new cutscene each time, eventually collecting the hygrocybe rubescens item off its back. Now go inside the Nest and cook/eat/sleep until a cutscene occurs where your characters eat the item and experience a unique situation. There seems to be an order to the cutscenes in the game, so depending on which ones you already saw, this may not come up right away but keep trying.

Here is a video demonstrating this (achievement spoiler warning):

_{Note: Achievement information supplied by XBOX Achievements.}