Rats will eat anything they find, and this includes mice. This act of killing and eating the mice is known as muricide. It is a stereotyped behavior in the rats. Muricide takes place because of hunger or the environmental conditions. However, the mouse killing can also be the result of the neurotransmitter signals found in the brain of the rats. The rats will attack and then eat the mice if they don’t have enough food and they feel hungry. The wild rat likes to eat the carcass when they finish killing them, and this includes the liver and neck. The domestic rats will eat the brain of the prey. There is a predator and prey relationship between the mice and the rats, and the mice are mostly cautious when they find rats or when they smell the urine of rats. The presence of rats will affect the reproductive and behavior mechanisms of the mice.
At least 70 percent of wild rats and 12 percent of domestic laboratory rats will kill mice. Both females and males will kill mice. When the rat is killing the mouse, it will aim at the upper back, neck and head.
The first bite will be fatal, but the mouse can delay the attack of the rat when it tries to defend itself. However, in the end the rats will deliver the fatal bite. The mouse killing is quick and it lasts only a few seconds. The common place in which rats bite mice is on their back and they aim for the spinal cord. Some have been bitten on the belly while others are bitten on the head.
When the rats finish killing the mice, they will eat a part of them. Within 7 hours of being killed, everything of the mouse will typically be eaten, including the abdominal and thoracic viscera and the brain. However, a few mice may not be eaten. The rat will start to eat the mouse at the place where it had bitten. They then open the thoracic viscera to go to the liver afterwards. Domestic rats eat the brain right away by opening the skull, and they eat the entire brain, regardless of the method that they used to kill the mice. Mouse killing is the result of the neurotransmitter system, hormonal system and neural system. It can also be a result of environmental conditions, social conditions, learning and rearing. Rats like to kill mice during the night compared to day time. The rats that have been raised with mice will not kill them when they became an adult; however, they may kill strange mice.
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