Assessing Nest Building Behavior in Mice

In mice, nest building is an ethological and relevant behavior involved in heat maintenance, reproduction, and shelter [29 (link)]. Mice were individually housed, and they were provided with two Nestlets (a 5 cm square of compressed cotton-like material weighing approximately 2.4 g; purchased from Ancare, Bellmore, NY, USA), which were placed in the cage at 10:00. At 1 h and 24 h later, the quality of the nest built was evaluated by a researcher trained and blind to the experimental conditions [30 (link)]. The scoring system for assessing nest quality was carried out based on Deacon’s standardized scale from 1 to 5.