A fainting goat is a breed of domestic goat
whose muscles freeze for roughly 10 seconds when the goat is startled
or excited. Though painless, this generally results in the animal
collapsing on its side. The characteristic is caused by a hereditary genetic disorder called myotonia congenita.
When startled, younger goats will stiffen and fall over. Older goats
learn to spread their legs or lean against something when startled, and
often they continue to run about in an awkward, stiff-legged shuffle.