how do some animals know when eg a volcano is going to erupt and escape?

Question: how do some animals know when eg a volcano is going to erupt and escape?
- Keywords:
  animal,
  erupt,
  volcano
Asked by confuddled213 to Mike, Pip, Tianfu, Tim, Tom on 28 Jun 2012.
- Tom Lister answered on 28 Jun 2012:
  
  Perhaps they get spooked by noises, changes in temperature and the increase in humidity?
- Tim Stephens answered on 28 Jun 2012:
  
  I’ve heard it said that lava moving under the ground causes small earthquakes, and the animals can sense that.

Question: how do some animals know when eg a volcano is going to erupt and escape?