How Well Do Rats Hear?
WouterRats’ hearing thresholds vary widely. One study found that the animals’ thresholds were highest at low frequencies, like 0.25 kHz. They had the lowest thresholds at mid and high-frequency ranges. The high-frequency range was slightly increased, with a higher threshold at 32 and 64 kHz. Rats’ responses were evaluated in pseudo-trials with a low sound pressure that would guarantee random behavior that would not meet audibility criteria.
Rats have auditory systems with two layers. One layer is the cochlea, which is responsible for producing sound. Another layer is the middle ear, which contains the ossicles. The cochlea develops in the first two weeks of life. During these first two weeks, the rats’ hearing abilities begin to become apparent. Rats may begin to hear a broad range of sounds as early as 12 days after birth, but their hearing capacity decreases as they age.
While humans can detect only a few thousand hertz, rats have exceptionally good hearing. In addition to being able to recognize sounds up to 20kHz, rats are able to detect ultrasonic sounds up to 20,000kHz. This is more than twenty times higher than human hearing. Rats can hear the sound of rubbing their fingers together, which is a high-pitched sound that is inaudible to human ears. Therefore, rats can hear noises at these high frequencies, which enables them to communicate with other animals and find food sources.
In addition to being able to hear and see, rats can sense depth, which helps them to navigate in difficult-to-reach locations. They also have the ability to detect changes in atmospheric conditions, which allows them to prepare for weather conditions like freezing temperatures and storms.
