often, these structures incorporate sophisticated features such as temperature regulation, traps, bait, ventilation, special-purpose chambers and many other features. they may be created by individuals or complex societies of social animals with different forms carrying out specialised roles. these constructions may arise from complex building behaviour of animals such as in the case of night-time nests for chimpanzees, from inbuilt neural responses, which feature prominently in the construction of bird songs, or triggered by hormone release as in the case of domestic sows, or as emergent properties from simple instinctive responses and interactions, as exhibited by termites, or combinations of these. the process of building such structures may involve learning and communication, and in some cases, even aesthetics. tool use may also be involved in building structures by animals.