Among humans, smile is an expression of pleasure, happiness or amusement. A genuine smile often show teeth. Among animals, the exposure of teeth, resembling to a human smile, is a threat or warning.
Here’s a smiling shark.

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Tags: animals, expression, genuine smile, happiness, pleasure, shark, teeth, Threat, warning
Posted in Smile, Threat
[...] our “Smiling shark” post, friends accused me of false imagination and challenged me to prove that shark [...]