Submissive body language

Submissive body language

A significant cluster of body movements is used to signal fear and readiness to submit.

This is common in animals, where fighting (that could terminally harm each animal) is avoided by displays of aggression or submission.
Body positions

The body in fearful stances is generally closed, and may also include additional aspects.
Making the body small

Hunching inwards reduces the size of the body, limiting the potential of being hit and protecting vital areas. In a natural setting, being small may also reduce the chance of being seen. Arms are held in. A crouching position may be taken, even slightly with knees slightly bent. This is approaching the curled-up regressive fetal position.
Motionlessness

By staying still, the chance of being seen is, in a natural setting, reduced (which is why many animals freeze when they are fearful). When exposed, it also reduces the chance of accidentally sending signals which may be interpreted as being aggressive. It also signals submission in that you are ready to be struck and will not fight back.
Head
Head down

Turning the chin and head down protects the vulnerable neck from attack. It also avoids looking the other person in the face (staring is a sign of aggression).
Eyes

Widening the eyes makes you look more like a baby and hence signals your vulnerability.

Looking attentively at the other person shows that you are hanging on their every word.
Mouth

Submissive people smile more at dominant people, but they often smile with the mouth but not with the eyes.
Gestures
Submissive gestures

There are many gestures that have the primary intent of showing submission and that there is no intent to harm the other person. Hands out and palms up shows that no weapons are held and is a common pleading gesture.

Other gestures and actions that indicate tension may indicate the state of fear. This includes hair tugging, face touching and jerky movement. There may also be signs such as whiteness of the face and sweating.
Small gestures

When the submissive person must move, then small gestures are often made. These may be slow to avoid alarming the other person, although tension may make them jerky.


Source: http://changingminds.org/techniques/body/