A system and method for monitoring the health of an animal using multiple sensors is described. The wearable device may include one or more sensors whose resultant signal levels may be analyzed in the wearable device or uploaded to a data management server for additional analysis. One or more embodiments include variations of the sensor system to accommodate differences in animals, including tracking vital signs over a period of time and comparing recorded values with an individual or species-based trendline. A deviation from the trendline may be signaled by alerting a user associated with the device about the deviation.