A new application of IR sensors for the detection of game is presented. The device detects wildlife (mammals, birds) by using the difference in IR radiation of wildlife and its environment (meadow, field). The system can be used to save the animals’ lives during mowing actions as well as for wildlife management purposes such as surveying and registration. The aspects of development and system layout are explained. The design is based on a model that describes the scenario (radiation, dynamics) and the features of important components (optics, detector, electronics). With reference to the simulation results, the device is constructed and basic optoelectronic parameters are investigated. First experiences concerning field measurements are given.