Aging cheetahs using gum‐line recession and evaluation of expert‐based aging techniques

Accurate aging is a useful tool in wildlife management, providing critical information for population dynamics research, age‐specific limiting factors, and conservation efforts. Many methods used to age mammalian carnivores are either invasive, expensive, or inconvenient to use in the field. In felids, the gum‐line recession has been found to accurately estimate the age of female mountain lions and tigers. In contrast, expert‐based aging techniques used on cheetahs (Acinonyx jubatus) can only categorize adults into broad age classes. We assessed whether the gum‐line recession of the upper canine teeth provides reliable information for aging cheetahs by using measurements on cheetahs of known age (n = 37) in sex‐specific linear models. We found a significant positive relationship between gum‐line recession and known age for both female (n = 21) and male cheetahs (n = 16), and we contribute herein sex‐specific regression models that can be used to age the animals based on the gum‐line measurements collected during handling. In addition, we compared expert‐derived age categories assigned to cheetahs of unknown age (n = 23) to the ages estimated by the gum‐line recession models. Expert‐based aging produced similar results to gum‐line recession for some individuals, but the ages of other individuals were underestimated by biologists, particularly for older cheetahs. Our data show that gum‐line recession measurements provide biologists with a reliable, minimally invasive, and convenient technique to age cheetahs in the field, and we encourage validation of this technique in other field‐intensive projects involving felid capture.