The gopher snake uses its glottis to produce a hiss that sounds similar to a rattlesnake's rattle. what is the most likely reason a gopher snake would do this?

The gopher snake has evolved to mimic the rattlesnake's rattle. This is because the rattlesnake is known to be highly venomous, and therefore predators tend to avoid rattlesnakes. In the animal world, mimicry has evolved because it provides the mimic a selective advantage. Mimicry is often employed to protect a species from predators; it is therefore an antipredator adaptation.