Rats generally aren't the noisiest of animals. Despite that, they are indeed capable of vocalizing. In times of mating, Norway rats (Rattus norvegicus) give off ultrasonic vocalizations. Ultrasonic sounds are simply too piercing for people to detect, so if a rat does call during mating, you definitely won't hear it.
Mating Acts and Rats
Mating vocalizations in rats generally occur during the acts, rather than before them. Male rats typically approach the females from the back. When this happens, the females become motionless and assume mating stance, or lordosis. Mating-ready female rats generally make their limbs rigid, curve their backs and elevate both their tails and heads, enabling the males to mate with them. Copulation is brief and generally only lasts for a fraction of a second. They do this over and over until the male rats finally release semen. When this goes on, male and female rats alike give off mating calls of 50 kHz.
Calls After Mating Acts
Right after male rats complete their mating acts, they go into a phase of inactivity, generally lasting about five minutes. During this phase, they ignore the females entirely. Although still, they do make sounds of 22 kHz -- these sounds are thought to keep other nearby males from attempting to mate with the same females.
Purposes of Calls
When male rats vocalize at 50 kHz, the sounds are believed to trigger mating actions in the females. When female rats are on the verge of mating, they often move swiftly to the front. They sometimes move around in fast circles, too. These actions, along with general mating positions, often indicate to male rats that mating can commence. When the female rats vocalize, they can encourage sexual reactions in the males, as well.
Ultrasonic Vocalizations and Rats
Although rats can exchange ultrasonic sounds with each other, such as those employed during mating, they're not believed to be overly helpful to them. Ultrasonic vocalizations are directional and can't be heard behind them. They also rapidly become more faint with a little distance.
Rats and Other Sounds
If you own a pet rat and can hear him vocalizing, it could indicate a couple of situations. Rats sometimes vocalize in times of aggression and play. They also sometimes do so when they feel physical discomfort. These vocalizations sound like squeals and are notably shrill.
- PubMed: Changes in Mating Vocalizations Over the Ejaculatory Series in Rats
- Carolina Pet Rescue: About Rats
- Illinois Department of Public Health: Norway Rats
- McMaster University Inabis '98: The Role of Vocalizations in the Behavioral Regulation of Reproductive Behavior in Rodents
- SmallAnimalChannel.com: Rat Makes Strange Sound