At present, there is no reliable coyote contraceptive, but USDA researchers are testing potential drugs. In a parallel effort, other USDA scientists are working to develop scent attractants to ensure targeted delivery of whatever prophylactic their colleagues come up with. It's not as easy as you'd think. In other words, attractants have to bring coyotes to the birth-control dispenser and then make them roll and scratch in the substance, creating a delivery method for the drugs. Researchers have noted that different scents or combinations elicit different behaviors in coyotes.
Some scents produce rolling, others rubbing or scratching, and so on.
The basis for some of the scents is sometimes strange. A lure scent in use by trappers since 1973, DRC-6220 or synthetic monkey pheromone, is based on a fatty acid found in secretions of the female rhesus monkeys. In an effort to develop simpler and more reliable fragrances to optimize effectiveness, Kimball selected 33 complex coyote attractants for chemical analysis.