Marking the un-markable: visible implant elastomer in wild juvenile snakes

Marking individuals is a key component of many ecological studies, but with some animals, such as juvenile snakes, it has proven problematic because of size constraints. This impedes our understanding of their habits in the wild. We marked juvenile Aesculapian snakes (Zamenis longissimus) in North Wales with visible implant elastomer (VIE), and recaptured them the following season. Our results demonstrate that the use of VIE is an effective marking method for small snakes, negating the need for tissue removal when marking. We suggest it represents a promising development in the ecological study of snakes, and is especially useful in species that undergo ontogenetic pattern changes.