A selective intrusion detection system includes a Doppler transceiver configured and adapted to receive Doppler return signals indicative of moving targets present in a surveillance space. A processor is operatively connected to the Doppler transceiver to convert Doppler return signals into spectrograms and to determine whether any given spectrogram is indicative of presence of a human or another moving target, like a domestic pet. An alarm is operatively connected to the processor, wherein the processor and alarm are configured to provide an alert in the event the processor determines any given spectrogram is indicative of a human, and to forego providing an alert in the event the processor determines any given spectrogram is indicative of another moving target only.