"Every four days, a ranger is killed in the line of duty."
So begins the final video in the World Wildlife Fund's comprehensive and troubling series, "Stop Wildlife Crime." The short film highlights the ongoing, and increasingly violent, efforts by wildlife rangers to protect endangered species including elephants, rhinos and tigers.
Demand for both ivory and rhino horn has skyrocketed in recent years. Nearly 700 rhinos have been slaughtered in South Africa this year, surpassing last year's record of 668. Wildlife experts also estimate more than 35,000 African elephants were killed in 2012.