Chances are, if you watch internet videos, you're familiar with the phenomenon of "fainting" goats. Whenever these peculiar little goats are startled, they dramatically freeze up and keel over, like a character in a daytime drama. A few seconds after, they are fully recovered and scampering around once more.
Many can't help but laugh when watching these goats fall down, assuming it's just nature's sense of humor. However, the story behind these swooning goats isn't quite so simple.
When animals (or humans, for that matter) are surprised suddenly, their muscles tend to tense up momentarily before relaxing again. Myotonia congenita is a hereditary condition which does not allow for contracted muscles to relax quickly. According to Dr. Phillip Sponenberg, the condition is caused by "changes in the ion channels in the muscle cell membranes." Myotonic, or "fainting" goats have this genetic condition, so whenever they are remotely startled, their muscles lock up and do not release for a few moments, causing them to fall over. The goats don't actually lose consciousness when they "faint." The perpetuation of the myotonic goats is largely a result of selective breeding, as this particular hereditary trait would likely have been phased out in wild goats due to natural selection.