Snakes know how much venom they have and won't attack if running low

Pit vipers are notoriously aggressive, but whether or not they choose to bite something that disturbs them may depend on how much venom they have in reserve

Snakes know how much venom they have and won't attack if running low
Pit vipers are notoriously aggressive, but whether or not they choose to bite something that disturbs them may depend on how much venom they have in reserve