Sneer

A sneer is a facial expression of scorn or disgust characterized by a slight raising of one corner of the upper lip, known also as curling the lip or turning up the nose. In The Expression of Emotions in Man and Animals, Charles Darwin defined a "sneer" as "the upper lip being retracted in such a manner that the canine tooth on one side of the face alone is shown" Darwin related the sneer to the snarl observed in non-human animals, particularly carnivores, observing that:

It is suggested that the sneer is a universal expression of contempt and that Darwin was the first to observe this. Cats may be observed to sneer, though this is probably related to the Flehmen response.

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