Gaping (animal behavior)

For example, "[i]n many species of reptile, the oral mucosa may be a bright color that serves to distract the predator".

[1] Gaping is part of the shark agonistic display, and is also found in snakes such as the cottonmouth, and in birds ranging from seagulls to puffins to roosters.

A number of species of bird use a gaping, open beak in their fear and threat displays.

[4] Both male and female puffins use gaping as a prominent part of their threat display, with "a range of intensities" based on the situation, and with puffins engaging in territorial gape contests, where they mirror each other until one gives up and leaves, or an actual fight occurs.

Other snakes, such as the Western Massasauga, have been observed to engage in gaping behavior which "appears to be unrelated to any threat".