Jul 27, 2011 – Food is Food is Food

QUESTION:

Do rats eat mice? Is this why they are never seen in the same environment?

ANSWER:

Given the opportunity I believe rats definitely would eat mice, and they may even get this opportunity if they were to come across an undefended nest with baby mice in it. Rats are omnivorous, meaning they feed on just about anything, and this includes both fruits and other plant products as well as meat. Roof rats have been responsible for terrible losses of nesting birds, eating the eggs or the young birds in the nests in trees. Norway rats also feed on eggs and young they may find as they forage at ground level. Meat is necessary protein, and being opportunistic in their feeding habits I believe rats will eat anything available.

However, adult mice are probably a harder prey to capture, so I would bet that rats don't make a regular diet out of adult mice, unless they find mice that are injured and unable to escape. What is more likely perhaps is that rats are like any other animal, and they aggressively protect their own resources. We have been told that the larger Norway rats will dominate over Roof rats, likely chasing them away when competition for food seems inevitable. Wild animals have a hard time with the concept of sharing. Probably a good origin for the expression "It's a dog-eat-dog world out there". This also may explain why Norway and Roof rats evolved slightly different habitats - Norways more at ground level and Roof rats in the trees, and as Dr. Corrigan once stated it, Roof Rats are "arboreal" - they evolved to living in trees, and this is why they can climb so well.

With limited food resources I think that Norway Rats simply won't tolerate the presence of other kinds of rodents that may steal those resources, and being so much larger they have the bulk to back up their claim to that food.

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