Air-Filled Pouches Found to Be the Key to Cool-Headed Horses

How horses keep their brains cool during intense exercise has been something of a mystery, but Canadian and Danish researchers have now figured it out, according to a report in today’s issue of the journal Nature. Most athletic animals have some mechanism for brain cooling because high temperatures can kill brain cells.

The researchers surgically implanted small temperature probes at various points on horses’ internal carotid arteries, which supply blood to the brain. They found that cooling was achieved by passage through so-called guttural pouches on each side of the head. The air-filled pouches, about half a liter in volume, are part of the animal’s auditory tubes. Similar pouches have been observed in hoofed animals with odd numbers of toes, some bats and a South American forest mouse.

--Compiled by Times medical writer Thomas H. Maugh II