What will a rat do with a mouse? - briefly
A rat usually treats a mouse as prey, killing and eating it when the opportunity arises. Occasionally, the larger rodent may only chase the mouse away without consuming it.
What will a rat do with a mouse? - in detail
Rats and mice often encounter each other in shared habitats such as urban sewers, agricultural storage facilities, and laboratory cages. Both belong to the order Rodentia, but differences in size, aggression levels, and dietary preferences shape their interactions.
Possible actions a rat may take toward a mouse include:
- Predatory behavior – Larger rats frequently hunt smaller mice. The rat stalks, seizes with its incisors, and delivers a quick bite to the neck or spine, resulting in immediate death. This reduces competition for food and grants the rat a protein source.
- Territorial aggression – Rats defend nesting sites and food caches. When a mouse enters a rat‑occupied burrow, the rat may chase, bite, or physically displace the intruder, forcing it to retreat to a peripheral area.
- Resource competition – In environments with limited grain or feed, rats outcompete mice by monopolizing storage containers. The rat’s stronger jaws and larger body enable it to break sealed packages, leaving fewer resources for the mouse.
- Disease transmission – Close proximity allows rats to spread pathogens such as hantavirus, leptospira, and Salmonella to mice through contaminated droppings, urine, or saliva. The mouse may become a secondary host, perpetuating the disease cycle.
- Coexistence under certain conditions – In abundant settings where food is plentiful and shelter is ample, rats may tolerate the presence of mice. The mouse occupies peripheral niches, while the rat maintains control of central resources, minimizing direct conflict.
Each of these outcomes depends on factors such as relative size, population density, food availability, and environmental stressors. Understanding the specific context clarifies why a rat might hunt, dominate, share space with, or inadvertently endanger a mouse.