Reindeer are hungry in the Arctic because of global warming. It causes temperatures to fluctuate more, meaning the snow melts and refreezes, becoming rock-hard ice that Santa's little helpers can't break through to get the tasty lichen underneath. But researchers have figured out a simple solution for the reindeer: cut their balls off.

Castrated reindeer stay fatter and healthier during the mating season, and they're bigger, so they can break through the ice more easily, Discover's Patrick Morgan explains. Even better, castrated males are nicer--they're more willing to give the reindeer kiddos a share of their lichen. To save these animals, scientists want to castrate enough to make the herd healthy but not so much as to cut the birthrate.

The Sami, people indigenous to the Arctic, depend on reindeer, and traditionally castrated reindeer by biting off just one testicle with their teeth. That moderates their testosterone--enough to make them strong but still docile. Those animal-lovers in the Norwegian government outlawed castration-by-teeth, but new vaccines are being developed that would mimic "half-castration."