Table 1.

Behavioural categories and the specific behaviours used to classify weaned grey seal interactions in pen trials

Behaviour analysed	Specific behaviours included in category	Definition
Affiliation	Approach	Distinctive locomotion towards subjects, starting with the individuals separated by more than one body length and ending within one body length of each other.
Investigative (checks)	Visual check	Subject raises head above ground and makes a definite movement to look specifically at the other trial individual.
	Olfactory check	Subject approaches subject and extends the snout towards the other’s face, anogential region or any other part of the body with nares open and forward extension of the vibrissae. Physical contact with the other individual may or may not occur.
Aggressive	Open mouth threat	Head held low but above the ground, neck extended, mouth open. May be accompanied by other aggressive behaviours (see below).
	Vocalisation	Any hissing, growling or howls uttered while interacting with the other trial animal.
	Flippering	One or both fore flippers brandished rapidly at the other subject, may or may not come into physical contact.
	Lunge	Bite attempt, neck extends rapidly and then retracts without contact with the subject.
	Bite	Actual physical contact of one animal’s open mouth to any part of the other subject’s body, in a rapid and aggressive manner.
	Startle	Visible, physical startle response, typically a violent jumping or flinching action.
	Flee	Rapid locomotion away from the other subject, resulting in separation of more than one body length between the two individuals.