Abstract: An animal detection and deterrent system enabling an out of doors area to be protected from intruding animals. A primary laser beam FIG. 1 (1.14) is produced from master laser/sensor (1.10), and precisely forwarded around an area of any configuration and topography via forwarders (1.11), (1.12), (1.13) or FIG. 10 (10.39), (10.40) and (10.41). Master laser/sensor (1.10) and all forwarders, contain mechanisms to accurately adjust the direction of laser beams and position of light sensors. Light sensors contain filters to block ambient light and admit only laser light to allow operation in bright sunlight or darkness. When the system is in a stable “on condition”, the laser beam ultimately strikes light sensor (6.65) in the master sensor (1.20). An animal interrupting the laser beam, at any point in the periphery, prevents laser light to strike light sensor (6.65) in master sensor (1.20). This causes light sensor (6.65) to initiate an electronic signal to an electronic circuit, FIG. 14, and microprocessor (14.