Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz (Hertz) or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing infrasound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.

New Mexico – Brenda Harris, has had encounters with Bigfoot from the mid 1990's to the present. This has prompted her to do more investigations and continuous research on the subject. Brenda Harris has investigated Bigfoot sightings and activities for years. "Bigfoot is something that the people on the reservation are dealing with right now in different areas," she said. "For people living along the rivers, they hear it yelling or screaming late at night. Brenda will give us an update on whats going on.