Yes, rats do kill rats. This adaptive behaviour of rats is referred to as muricide which is a predatory in nature. According to research, rats killing mice is a common behaviour portrayed in both the male and female counterparts. They are born with the killing instinct and so you would expect a young rat to bite or even kill a mouse if it encounters one.

What happens when a rat encounters a mouse? It will go for the hunt. The mouse is also born with the fear of rats. If it sees one, the mouse will run away from the rat for safety as the end result is very fatal. The chase then begins. The mouse is not easy on giving up on the chase so is the rat till it catches up with the mouse. The rat will ambush the mouse by biting the mouse’s head, neck or upper back with its sharp front incisors. When face to face with an enemy, the level of aggression is at its maximum, with nothing to hold back. The rat is no less to this aggressiveness. The first bite is usually fatal but this will not weaken the mouse to give in just like that. The mouse will try to fight back and defend itself by rearing up and boxing using its front paws while lying on the back. The struggle between the two may go on for a while before the rat strikes for the second time, even worse than the first time. This will finish off the mouse in just a matter of seconds.



This kill is not just an enemy but a good meal for that matter. Rats will consume the mouse, especially during those times when food is scarce. Otherwise, when there is food in plenty, the rat will only eat a few selective parts the brain, the liver and the fleshy parts.

One may wonder why rats kill mice. First, it’s stereotype i.e. the in-born instinct of nature. Apart from that, rats will kill mice for food. Scarcity of food will result in a higher number of mice killing by rats to feed on. Other factors include environmental factors for instance a rat is more likely to kill a mouse at night than during the day. Contrary to their nature, a rat that has been reared with a mouse (petting for that matter) is less likely to kill a mouse due to the familiarity.

As for mice, rats are their mortal enemies hence a slight chance of rat presence detected by their odour sends a mouse into stress. This will result in behavioural changes such as less eating and also their rate and time of reproduction shifts to low rates and less amounts per litter.

Read the How to get rid of rats page for helpful information and to learn more about Do rats kill mice?

Do rats kill mice?