A new study discovered that giraffe survival and reproduction differed among five sites in Tanzania, and also differed among six national parks in East, South, and West Africa. The study, by researchers at the Wild Nature Institute, Tanzania National Parks, Dartmouth College, and the School for Field Studies and published this week in the Journal of Mammalogy, found that even in national parks where wildlife are presumed to be safe and protected, vital rates of survival and reproduction varied widely. Dr. Derek Lee, Principal Scientist of the Wild Nature Institute and lead author of the study said, "People often assume every national park is successfully protecting the wildlife there, but we found not all parks are the same for giraffes."

The study examined reproduction, adult survival, and calf survival, and found that all of these vital rates varied among the study sites. However, the most important factor determining whether a population was growing or declining was the same everywhere. "In northern Tanzania, and across the continent, adult female survival made the greatest contribution to local population growth rates, and lower adult female survival was related to human-caused effects" said Lee.

The study indicates that protected areas, including national parks, cannot assume they are effectively saving wildlife, but should closely monitor their populations to ensure the species under their care are truly benefiting.