Rats are nocturnal animals and they have rather poor vision. They avoid areas with a light intensity of > 25 lux. Their sense of smell, touch, and hearing is well developed. The animals perceive and are sensitive to ultrasound (>20kHz). Rats communicate with each other by means of pheromones and (ultrasonic) vocalizationsVocalisation Sounds produced by animals that may or may not (ultrasound, infrasound) be audible to humans. The rat associates 20 kHz sounds with fear or pain and 50 kHz sounds with pleasant situations.. Of the sounds they produce, a frequency of ~20kHz is associated with pain or discomfort (see movie 1), and a frequency of ~50kHz with increased well-being (see movie 2). Specific ultrasonic calls are produced in aggressive and sexual situations and mother/pup interactions.

Pheromones

pheromones play an important role in rat communication. Pheromones are emitted to warn conspecifics of danger, to scent-mark territories, to interact with the opposite sex etc. In rats as in mice, the olfactory organ is the most important sense organ.

Whiskers

Rats also have well-developed whiskers. Bending of whiskers by touching or via movement of air, leads to a nerve impulse that registers in the cerebral cortex.