Stanhope, J.Weinstein, P.2025-05-302025-05-302023Vet Record Case Reports, 2023; 11(1):e506-1-e506-22052-61212052-6121https://hdl.handle.net/2440/144820Ear punching and notching are commonmethods of identification of laboratory rodents. Concerns have been raised regarding pain and discomfort, infection, thermoregulation and tearing. However, the evidence regarding these potential adverse events is currently limited. In this case report, we describe an unusual complication of ear punching in a laboratory mouse. The mouse had its left ear punched with a single hole at 3 weeks of age. At 11 weeks of age, the mouse caught its left foreleg through its left ear punch up to the level of the shoulder. The mouse’s leg was released and the pinna cut to forma notch rather than a hole. To avoid this situation, we suggest that an ear notch be considered rather than an ear punch. This case also highlights the value of daily checks to ensure that the risk of any adverse effects from such unpredictable events is minimised.en© 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in anymedium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.Ear punching; notching; laboratory rodents; Concerns and side-effectsJournal article10.1002/vrc2.506621827Stanhope, J. [0000-0002-6657-3317]Weinstein, P. [0000-0001-9860-7166]