By Alice Klein
Horses in New Mexico have been shot with darts containing a long-acting contraceptive
infocusphotos.com/Alamy Stock Photo
Shooting wild horses with contraceptive darts may help curb their numbers in parts of the US where their populations are ballooning out of control.
Horses were reintroduced to the US by the Spanish in the 16th century, after native North American horses went extinct about 10,000 years ago. Lacking natural predators, they have since spread across the rangelands in the western US.
More than 70,000 wild horses now occupy public rangelands, about 45,000 more than the limit set by the US …