Table 3.

Overview and description of the different gesture types produced by red-capped mangabeys during this study

Gesture name	Description
Visual gestures
1. Crouch	Subject is in crouching position on the ground in front of the other, belly touching the ground, on four legs
2. Head bob	Subject makes short forward movement of the head, ‘lunging’ its head towards the other, while staring at the other intently
3. Head shake	Subject moves head in quick, jerky movements in front of the other, horizontally and/or vertically
4. Hop	Subject jumps/ hops in the air with both feet leaving the ground, either in one position or moving around in front of the other
5. Lie down wiggling	Subject is lying down on its belly in front of the other, wiggling its body at the same time. This can also occur with one arm extended towards the other, with body and arm wiggling at the same time
6. Make grabbing movement towards*	Subject throws arm towards the other with hand closing at the end of the movement
7. Move arm in front*	Subject puts its arm with elbow flexed in 90° in front of its face or its body
8. Present body part	Subject exposes one particular body part to the other, by orienting its body appropriately. Subject can present different body parts (including back, belly, rear, neck, penis, head, side) using different postures. This occurs in three main positions: while seated, standing, or lying down rigidly (subject is lying down on the belly or on the back in front of the other, not moving, exposing body part). At least 25 different varieties of this signal were recorded (e.g. present back seated arms relaxed, present back seated one arm up, present back seated two arms up, present back lying on belly, etc.)
9. Roll on ground	Subject rolls on the ground in front of the other
10. Somersault	Subject jumps and makes a forwards or backwards salto/flip
11. Swing body	Subject moves its body in quick movements in front of other: swinging its body from side to side, seated, arms relaxed
12. Throw arm towards*	Subject extends and throws arm (arm extended) with hand open, palm facing down, towards the other in a brief, quick movement
13. Throw body towards	Subject throws its upper body in direction of other, with two hands and arms stiff, thereby hitting the ground or support
14. Throw hand towards (hand fling)*	Subject ‘throws’ one hand towards the other in a brief movement, with hand open, palm facing down, no movement of arm
Tactile gestures
15. Embrace	Subject puts one arm or both arms around the body of the other, dorsally (by the back) or ventrally (by the front)
16. Grab body part	Subject grabs a body part of the other with its hand or feet, without pulling body part. The subject can hold the body part briefly (< 1 s) or longer (> 1 s). Body parts include: top of the head, arm, hand, penis, tail, hips
17. Hit/slap body part	Subject hits a body part of the other with a flat hand, in a quick movement (< 1 s). Body parts include: top of the head, limb, back, hand, tail
18. Put body part on other	Subject places its hands or feet gently on a body part of other (> 1 s). Body parts of others include tail, arm, top of the head, back
Audible gestures
19. Kick object	Subject jumps in the air and stamps once on an object (e.g. cage) with two feet
20. Shake object	Subject holds and shakes an object or other support (cage) with its hands or with its hand and feet
21. Slap object	Subject hits/slaps the ground or an object (e.g. cage) with one or two hands

Gesture types are further specified per signal category (visual only, tactile, or audible signals). Manual gestures are indicated with *