Ratlings' battle experience has taught them that enemies who wait without moving or attacking anything are the most deadly. If they see such an enemy, they become extremely suspicious, and they also wait.
These reptiles are quite strange creatures. They spend most of their lives sleeping as floors that other creatures can walk on. Sometimes they wake up to hunt their prey, but they will happily go back to sleep if they happen to move into a hole on their way. Your attacks do not kill the Reptiles, but you can push and stun them.