To examine this issue, we conducted a longitudinal analysis of daily fantasy sports play on the DraftKings website. Understanding this is important because daily fantasy sports is an immensely popular activity that many have compared with traditional gambling. Currently, we know very little about whether these trends are evident for daily fantasy sports. Adaptation typically shows initial play increases followed by sharp betting (e.g., amount wagered and number of bets) declines. Abstract: Populations of gamblers can adapt rapidly to online sports betting services.