Table 3 Ethogram showing the categories used for describing the behaviour of the studied Prezewalski’s horses

Feeding

Feeding

Food acquisition and investigation, very slow movement connected to feeding is categorized as feeding and not as walking.

Locomotion

Lead

Movement to a particular direction while leading other group members, may be accompanied by head movements (up and down) and/or herding.

Follow

Move along the path of another horse (typically leading mare), usually at the same gait as the horse being followed. There is no attempt to direct the movement, attack, or overtake the leading horse.

Running

Fast movement to a particular place, fast movement towards and object or other horse is categorized as approach. Fast movement while following or leading some horse(s) is categorized as lead/follow.

Walking

Slow movement to a particular place, very slow movement connected to feeding is categorized as feeding, slow movement towards and object or other horse is categorized as approach, slow movement while following or leading some horse(s) is categorized as lead/follow.

Leaving the group

Movement performed in order to increase the distance of an individual from a group resulting in the group abandonment. The abandonment might last from several hours to days or become permanent

Coming back

Movement performed in order to decrease the distance of an individual from a group resulting in connection to the group. This behaviour typically follows leaving the group.

Resting

Standing alert

Rigid stance with the neck elevated and the head oriented toward the object or animal of focus. The ears are held stiffly upright and forward, and the nostrils may be slightly dilated. The whinny vocalization may accompany this stance.

Stand resting

Standing relaxed with head down.

Resting

Laying down.

Social

Approach

Movement of a horse in attempt to initiate a behaviour towards other horse.

Play

Behaviour appearing to have no immediate use or function for the animal, involving a sense of pleasure. Various behaviours presented while playing with other individual/s.

Grooming

Two members standing beside one another, usually head-to shoulder or head-to-tail, grooming (each) other’s neck, mane, rump, or tail by gentle nipping, nuzzling, or rubbing.

Head resting

Horse is placing it’s head on the other horse’s body.

Head rubbing

Horse is rubbing it’s head on the other horse’s body. Not connected to sexual activity.

Olfactory investigation

Olfactory investigation involves sniffing various parts of another horses’ head and/or body. Considered friendly if followed by another friendly behaviour.

Arched neck threat

Neck tightly flexed with the muzzle drawn toward the chest. Arched neck threats are observed during close aggressive encounters and ritualized interactions.

Bite threat

No contact is made. The neck is stretched, and ears pinned back as the head swings toward the target horse giving the warning to maintain distance.

Bite

Opening and rapid closing of the jaws with the teeth grasping the flesh of another horse. The ears are pinned, and lips retracted.

Chase

One horse pursuing another, usually at a gallop. The chaser typically pins the ears, exposes the teeth, and bites at the pursued horse’s rump and tail. The horse being chased may kick out defensively with both rear legs.

Ears back

Ears pressed caudally against the head and neck. Typically associated with intense aggressive interaction.

Fight

Various behaviours associated with fighting, not a single aggressive movement. More than one of the aggressive attempts must be present. Striking, rearing, mounting, lunge, levade, repeated biting/kicking.

Head bump

In two horses: a rapid lateral toss of the head that forcefully contacts the head and neck of another horse. Usually, the eyes remain closed and the ears forward.

Herding

Combination of a threat (usually bite) and ears laid back with forward locomotion, apparently directing the movement of another horse.

Interference

Disruption of combat of horses by moving between the fighting individuals, pushing, attacking, or simple approaching the combatants. One or more horses may simultaneously interfere with an encounter.

Kick threat

Similar to a kick, but without sufficient extension or force to make contact with the target. The hind leg(s) lifts slightly off the ground and under the body in tense “readiness”.

Kick

One or both hind legs lift off the ground and extend towards another horse, with apparent intent to make contact.

Push

Pressing of the head, neck, shoulder, chest, body or rump against another in an apparent attempt to displace target horse.

Retreat

Movement that maintains or increases an individual’s distance from an approaching horse or a horse initiating some behaviour. The head is usually held low, and ears turned back. The retreat can be at any gait, even very slow and little movement from the initiator.

Retreat chewing

Moving the lower jaw up and down in a chewing motion. A sucking sound may be made. Typically, the head and neck ate extended, with the ears relaxed and oriented back or laterally.

Threat

Giving the general appearance of a warning to maintain distance. Threats are typically not directed toward the particular part of the body of other horse.

Olfactory investigation social

Olfactory investigation involves sniffing various parts of other horses’ head and/or body. Considered agonistic if followed by another agonistic behaviour.

Copulation

Stallion mounting the female from behind, neck arched over her back and forelegs resting on her sides.

Copulation attempt

Attempt for copulation without successful completion.

Defecating over

Defecation over faeces of other group members (typically females) presented by the stallion in a characteristic sequence: sniff faeces, step forward, defecate, pivot or back up, and sniff faeces again.

Female presentation

Mare presents herself facing away from the stallion, lifting her tail, posturing her body with hind legs slightly apart and often turning her head toward her posterior.

Head rubbing (sexual)

Stallion proceeds by rubbing his head on the female’s flanks and (or) resting his chin on her back, usually extends his penis out of the prepuce.

Reproductive tending

Close following of an oestrous female by the male, without the directional driving observed in herding behaviour.

Sniffing faeces/urine

Sniffing, typically followed by flehmen, defecations and urinations performed by stallion towards faeces of females in oestrus.

Nursing

Recorded in mares. The foal’s muzzle is in contact with the mare’s udder, movement of milk down the oesophagus is visualized, or the foal is seen to grasp and hold the teat with its lips.

Suckling

Recorded in foals. The foal’s muzzle is in contact with the mare’s udder, movement of milk down the oesophagus is visualized, or the foal is seen to grasp and hold the teat with its lips.

Suckling attempt

The foal is trying to reach mare’s udder with its muzzle.

Vocalization

Emitting a sound produced through the action of respiratory system, used in communication.

Other

Defecating

The discharge of faeces from the body.

Drinking

The action or habit of consuming water.

Erection

Fully extended and tumescent penis.

Head bow

Repeated, exaggerated, rhythmic flexing of the neck such that the muzzle is brought toward the point of the breast.

Insect elimination

Waving of tail, kicking around and/or biting itself or hiding itself under the tail of another horse in attempt of insect elimination.

Masturbation

Erection with rhythmic drawing of the penis against the abdomen, with or without pelvic thrusting. Solitary or group activity (bachelors).

Solitary olfactory investigation

Olfactory investigation involves sniffing various parts of a ground or objects.

Rolling

Dropping from standing to sternal recumbency, then rotating one or more times from sternal to dorsal recumbency. Typically occurs on dusty or sandy areas.

Urinating

The discharge of urine from the body.