Changes in the environment can increase body temperature by impacting neural signaling to physiological systems including muscle and brown adipose tissue. We hypothesize that the “fight or flight” response can translate to weight loss due to muscle thermogenesis. The stimulus for the sympathetic nervous system response was the odor of ferrets, a natural predator of rats. This predator odor (PO; towel with ferret odor) induces a rapid and robust increase in skeletal muscle thermogenesis in rats. To test our hypothesis, each rat (N=10) was surgically implanted with temperature transponders (IPTT-300; Bio Medic Data Systems) adjacent to brown adipose tissue and skeletal muscle (gastrocnemius, bilaterally). To determine if this impacted energy balance, all rats were maintained on a 25% caloric restriction diet for 2 weeks, and half of the rats were exposed to a new PO towel daily; the other half received a control stimulus. On the 1st, 8th, and 14th day, muscle temperatures were monitored for two hours after exposure to PO or control. After one week, rats with daily PO exposure lost, on average, 13.4 more grams of body weight than the control group. All PO-exposed rats showed habituation in their PO-induced thermogenic response after 2 weeks, but not 1 week, of continuous exposure. Body composition measurements (EchoMRI-700) showed that, unexpectedly, most of the weight lost by PO rats was lean mass as opposed to fat mass. Exploiting the neural pathway underlying PO-mediated muscle thermogenesis could lead to novel weight loss strategies.