Indexing ages of antelope jackrabbits and other Leporids using x‐ray

Abstract

ABSTRACTThe ability to determine wildlife age classes is important for wildlife management and the key to understanding the life histories of species. We used radiograph images of the epiphyseal cartilage at the distal end of the radius and the age‐class criteria developed by Lechleitner (1959) for black‐tailed jackrabbits (Lepus californicus) to determine age classes for antelope jackrabbits (L. alleni) between 2011–2016. Using 2 known‐age antelope jackrabbits, we found that 3 developmental phases similar to those identified by Lechleitner (1959; class 1 [juvenile: <7 months], class 2 [subadult: 7–11.4 months], and class 3 [adult: >11.4 months]) were also applicable to radiographs of forelegs of antelope jackrabbits. Although requiring some interpretive experience, we consider this technique superior to other lagomorph aging methods because radiographs can be obtained from live and dead animals. Using this method, biologists can determine ages of individuals in the population, which would help to estimate recruitment rates and predict population changes. © 2017 The Wildlife Society.