Rats squeak with happiness when they are with another rat

Why do my rats occasionally vibrate when I hold and pet them? Purring? - Quora

How Does a Rat Ask for Help?

Rats squeak with happiness when they are with another rat

What rats need in their cage

OurPets Play-N-Squeak Twice the Mice Cat Toy, 2pc (Interactive Catnip Toy, Real Mouse Electronic Sound) : Everything Else

Some rats are more ticklish than others - and you can tell by how much they squeak with 'laughter

Man v rat: could the long war soon be over?, Science

Hide and squeak: scientists reveal the playful lives of rats

Rats “Bop to the Beat” of Music

Is it normal for my boy rats to always squeak at each other and do the pushing the other over “dominance” move but sometimes it turns into them chasing each other loudly.