https://youtu.be/g1s_2f4CaFM
A study on rats identifies the tickle hub of the warm-blooded vertebrate brain, shows that exciting a certain region can provoke an outbreak of ultrasonic happy squeals. The researchers found that rats are actually enjoying it. The ultrasonic shrills the rats make are expressions of pleasure. The tickling triggers the “neurotransmitter dopamine” in the brains of the rodents. Rats, dogs, foxes, lambs, guinea pigs, and human children all jump for joy by leaping into the air with both legs together. They also found that the tickling response was also seen as the rodent chased the ticklers hand and giggled. Also, ticklishness is mood-dependent as the rats are less ticklish when they are anxious. Another conclusion is that, like us humans, if rats aren’t tickled when they are young, they tend not to enjoy it as adults.
https://www.linkedin.com/pulse/tickled-rats-jump-joy-randy-bilesky?published=t
http://www.delta-optimist.com/living/blog-tickled-rats-jump-for-joy-1.2731880