Beyond hippos: Evidence of an introduced deer in Colombia

More than 18% of the cases of invasive mammals worldwide correspond to South America, including small rodents and large species such as deer and hippos. Among exotic mammals in Colombia, we can mention pigs (Sus scrofa), which are well established, mainly in the Orinoquía region of the country, and more recently, hippos (Hippopotamus amphibius) with a growing area of occurrence in the middle and lower basin of the Magdalena River in the inter-Andean zone. In May 2022, a spotted exotic deer was documented in the area based on direct and indirect observations (photographs and videos) of living individuals and a partial skeleton. The spotted pattern of the photographed adults (absent in native or other exotic deer) and the juvenile individuals and the shape of the antlers show that they are chitals (Axis axis), a species native to Asia. Compared with the white-tailed deer Odocoileus, the largest native deer species in Colombia, the Axis skeleton was one-third bigger, which corroborated the identification. According to local inhabitants’ communications, the number of Axis has increased, and groups of up to 18 individuals have been recorded. This is the first time that exotic deer have been documented in Colombia. Their presence may impact natural regeneration and competitively displace other native herbivores, which calls for the mitigation and control of the population since its establishment and dispersal can be cryptic.