Who Hit Pause? The Real Reason Some Goats Faint

Playful baby goats frolic and hop around in their straw-filled enclosure, showcasing their lively and spirited nature.

Fainting goats, officially called myotonic goats, are known for freezing and sometimes toppling over when startled. This fascinating reaction has gone viral more than once. While they might appear to be passed out, that's not actually what’s happening. They don’t lose consciousness, but instead they have a harmless genetic condition called myotonia congenita, which briefly locks up their muscles when they get surprised.

Why do these animals STOP MOVING?

When an animal is startled, the brain sends an electrical signal to the muscles telling them to tense up in preparation for fight or flight. In normal goats, the muscles contract and then immediately relax. In myotonic goats, the muscles contract normally, but take several seconds to relax. This sudden stiffness can make them freeze in place or even fall over in a rigid condition. After about 5 to 20 seconds, the stiffness fades and they walk off like nothing happened.

The condition comes from a mutation in a gene called chloride channel protein 1 (CLCN1), which controls chloride ion channels in muscle cells (Zhang et al. 1996). When an electrical signal reaches the muscle fibers, it triggers muscle contraction. After a contraction, chloride ions usually flow into the muscle fibers to calm them down and stop contraction in order to relax. However, in a myogenic goat, the chloride channels don’t work properly, so the electrical signal keeps firing longer than it should. The muscles struggle to relax because the chloride channel isn’t properly “stepping on the brakes” to regulate the electrical firing, which allows contraction to keep occurring and causes the brief stiffening (Beck et al. 1996).

You may be wondering, does this hurt them? Veterinary studies suggest that myotonia congenita is painless in goats (Atkinson et al. 1981). They learn to live with it and often adapt by spreading their legs or leaning on things when nervous. Some even seem unfazed, immediately hopping back up to continue eating grass.

Why did humans keep breeding them?

The mutation likely appeared naturally in Tennessee in the 1880s (Lush 1930). Farmers chose to breed them intentionally because they didn’t jump fences, and according to some stories, unintentionally protected the rest of the herd if a predator began chasing them first (Lush 1930). Later on, they were important in early physiological studies for researching and clarifying the role of chloride channels in muscle contraction (Beck et al. 1996). Today, most are kept as pets or novelty farm animals, or as internet sensations.

So the next time you freeze up when your boss asks an unexpected question, don't feel bad. You're not being dramatic; you're just channeling your inner fainting goat.

Written by Haley Culhane, BS, and edited by Aldrin V. Gomes, PhD.

References

Atkinson, J B et al. “Myotonia congenita. A histochemical and ultrastructural study in the goat: comparison with abnormalities found in human myotonia dystrophica.” The American journal of pathology vol. 102,3 (1981): 324-35.

Beck, C L et al. “Molecular basis for decreased muscle chloride conductance in the myotonic goat.” Proceedings of the National Academy of Sciences of the United States of America vol. 93,20 (1996): 11248-52. doi:10.1073/pnas.93.20.11248

Lush, Jay. “NERVOUS” GOATS, Journal of Heredity, Volume 21, Issue 6, June 1930, Pages 243–247, https://doi.org/10.1093/oxfordjournals.jhered.a103334

Zhang, J et al. “Mutations in the human skeletal muscle chloride channel gene (CLCN1) associated with dominant and recessive myotonia congenita.” Neurology vol. 47,4 (1996): 993-8. doi:10.1212/wnl.47.4.993