Table 1.

List and definitions of the play behavioural items used in the study.

play patterns used as control for the demonstration of rapid mimicry
bite attempt/bite (BITE)	the dog opens its mouth and then attempts to bite or bites another individual
jump attempt (JUMP)	just before a dog jumps on another individual, it starts from a semi-crouching position (jump attempt) and then leaps away. During the jumping attempt, the dog crouches on its forelimbs and remains standing on its hind-legs for a while
play signals
ROM	the mouth is relaxed and kept open at different gradients. The mouth can be opened (i) just a little revealing only the upper parts of the most forward teeth of the lower jaw and (ii) in a wider way completely revealing the lower and upper jaws [26]
PBOW	a dog crouches on its forelimbs, remains standing on its hind-legs, and may wag its tail and sometimes bark. The bow is a stable posture from which the animal can move easily in many directions, allows the individual to stretch its muscles and places the head of the bower below another animal in a non-threatening position [27]