Example systems and methods for detecting an animal proximate a vehicle are described. In one implementation, a wearable device carried by an animal is activated when the wearable device is within a predetermined distance of a vehicle. The vehicle receives a signal from the wearable device and determines an approximate distance between the wearable device and the vehicle. An alert is generated to warn a driver that an animal is near the vehicle. The alert has an intensity level that corresponds to the approximate distance between the wearable device and the vehicle.