|MadSci Network: Zoology|
Ants will relocate a colony for a couple of reasons. If the location of
the colony becomes uninhabitable (for instance, if someone nukes it with
pesticide), it will pick up and move elsewhere. Also, when a colony
becomes too large, it will sometimes "split" with part of the original
colony moving on to start a new one somewhere else.
Here's a couple of links with tons of ant facts:
Hope that helps!
Rob Campbell, MAD Scientist
Try the links in the MadSci Library for more information on Zoology.