It is well known that rats feel ticklish too, just like humans and enjoy some belly tickling time. You may not be able to hear or see the little beings laugh, but research suggests that rats do emit giggling sounds in the form of ultrasound waves, which cannot be heard by human ears. Rat lovers can certainly tell that their pet likes being tickled.

Rats may like being tickled on their backs or stomach, but scientists were able to find out exactly where they enjoyed most, with the help of electrode implantation. Much like humans, rats are sensitive to the sole of their feet and love being tickled the most on feet.
Tickle time for rats
It has been found that rats associated ticket time with play time and showed positive response when the hand approached them. They went back for the hand that caused them to giggle and also jumped around happily. This shows that rats find this playful and it helps in developing their social bond.
How to begin
Since tickling encourages social behavior and bonding time, you may want to introduce this to your rats as well. You must remember that not all rats like being tickled and they may not be in the mood every time, just like humans again. It is better to begin when they are really young, because research suggests that at this age, rats get used to the concept of tickling and enjoy it even as adults. Start by tickling lightly on their backs and necks first. See how they react for a few days. If they appear to show interest by touching your hand and hopping around in excitement, it means they love spending some tickling time with you. Do this in your regular play time with them and your rats will look forward to it every time.