Santa Monica city officials have said they will be giving squirrels a birth control shot in hopes of controlling the city's problem of squirrel overpopulation, which some health experts say is a public health risk. Officials will be injecting squirrels in Palisades Park with GonaCon, an immuno-contraceptive developed by the U.S. Department of Labor that stunts sexual development.

GonaCon stops female squirrels from ovulating and lactating and stops testicular development in male squirrels. Researchers say it takes about three months for the shots to show their effects.

Some health officials say squirrels can be aggressive and may have rabies or fleas that can spread disease.

AP quotes Joe McGrath, the city's parks chief, as saying, "We don't want to kill them if we don't have to. I personally like squirrels, but we have to be receptive to the county's concerns."

Some people, like animal activist Catherine Rich, don't think squirrels pose that much of a risk to human health.

"There is not a pressing threat of squirrels attacking people, so I don't know why the county is getting their panties in a bunch," Rich said.