| Many small mammals raise young in warm, sheltered locations, sometimes colonially, which mitigates the costs of thermoregulation while lactating. However, the hoary bat (Lasiurus cinereus) is a solitary tree-bat that gives birth among the foliage. I investigated the influence of roosting ecology and the development of thermoregulation on torpor use throughout lactation in this species. I found that reproductive females use torpor throughout lactation, and change the extent in response to ambient conditions and energetic requirements of growing pups. Juveniles spent little effort on thermoregulation and used torpor often, despite demonstrating the ability to stay warm on their own from an early age. Female L. cinereus chose maternity roosts based on microclimate. The migratory nature of L. cinereus may relax time constraints on reproduction, and allow for use of torpor when conditions favour, without detriment to the development and success of the young. |
