This chapter examines activity patterns among the middle Holocene foragers of Siberia’s Cis-Baikal in the context of a well-documented climate shift and biocultural transition dating to the Middle Neolithic (MN) period. Osteoarthritis and entheseal change activity data from four skeletal collections, two pre-dating the MN and two post-dating it, are discussed to more fully understand behavioral complexity and subsistence practices. Results indicate that the middle Holocene Cis-Baikal was characterized by variable activity patterns reflecting the dynamic relationships between local ecological conditions and social organization, with environmental change playing a secondary role. Indeed, the fact that overall subsistence and behavioral strategies remained relatively constant throughout the middle Holocene further suggests that climate change may not have been entirely responsible for the MN transition, but that human adaptability was also a key factor.