Rat behavior

Note: This is a draft that I did not publish, or finish, and is around two years old. Take it as you will.

'Ratty does want' behaviour...

If a rat does want to be petted, he will lower his head so you can rub his head.

If your rat does wants to go somewhere while on your shoulder/in your arms, he will nod their head and point their head in the direction they want to go.

If your rat does want to go to play time but its still not time, he will start climbing and biting the bars
of  his rat cage.

'Ratty doesn't want' behaviour...

If a rat doesn't want food, he will push it away with his hand.

If a rat doesn't want you to touch him, he will push your finger away.

If a rat doesn't want to be held, he will squeak and wriggle out of your grasp and run to a safe hiding place.

If a rat doesn't want to be petted or you've been petting him for too long, he will most likely nip your finger.

Other ratty behaviour...

If you hear a grinding sound, don't worry! Rats grind their teeth as a sign of affection and also just the keep their teeth sharp and short.
NOTE: Older rats will need YOU to trim their teeth! 

Rats hiss when stressed. This is normal for a new rat to do when placed in another cage withe your other rats after two weeks of quarantine.

Rats bulge their eyes  at the same time as grinding their teeth because a muscle in the lower jaw passes behind the eye and makes it bulge. This is usually done at times of relaxation, comfort and to
show affection towards you!

Rats yawn for three reasons: to show affection towards you OR after waking up OR because they're tired.

As rats get older and enter puberty, they will start fighting for dominance more aggressively and start jumping at each other.