why do mice kill and eat each other?

[Michael D]

i had 2 female mice this morning when i left for work, plenty of food and water in their cages, when i came home i had 1 fat live mouse and part of one dead one. any idea why this would happen?

[birdfun]

same thing happened to me but with males. maybe they got mad at each-other to this day i still wonder why my poor Zack had to be killed and eat! RIP Zack and your hamster!

[Fete]

Mice are territorial. Males more then females, but it's not unusual for mice to fight. Usually it's over space or food. The eating is just what they do to keep their territory clean so they don't attract predators.