Table 1 DogFACS variables (Action Units (AUs), Action Descriptors (ADs) and Ear Action Descriptors (EADs)) used in²².

AU101

Inner brow raiser

Protuberance above the eye moves dorsally and obliquely towards the midline

AU145

Blink

Both eyelids move towards and touch each other, covering the eye for less than 0.5 s

AU12

Lip corner puller

Lip corners move caudally

AU116

Lower lip depressor

Lower lip moves ventrally

AU25

Lips part

Any lip separation

AU26

Jaw drop

Lower jaw moves ventrally in a relaxed manner and teeth are separated

AD19

Tongue show

Tongue is protruded at least until the inner lower lip

AD137

Nose lick

Tongue moves out of the mouth towards the nose and wipes it

AD126

Panting

Mouth is open, tongue is protruded, and dog breathes shortly and quickly

EAD102

Ears adductor

Ears move dorsally towards the midline of the head; bases of both ears come closer together

EAD103

Ears flattener

Ears move caudally