The 'Sierra Sounds' recordings
In the early 1970s hunters at a remote camp in California's Sierra Nevada recorded whoops, growls and chatter they said came from Bigfoot, later analysed as a possible primitive language.
1972 CE · 38.50, -120.10 · status: disputed
The account
The recordings, associated with Ron Morehead and Al Berry, were studied by a retired US Navy cryptologic linguist, Scott Nelson, who argued they show language-like structure beyond human or known animal ability. They are among the best-known Bigfoot audio.
The sceptical view
Mainstream scientists attribute most 'Bigfoot' sounds to hoaxes or known animals such as owls, coyotes, foxes and wolves; the tapes cannot be tied to any particular source.
The researched reading
Intriguing night sounds on tape with no visible source and no independent control. Known animals, human mimicry and pattern-seeking explain them more easily than an unknown ape.
| Explanation | Weight | Why |
|---|---|---|
| Something known, misidentified | 34% | Coyotes, owls, foxes, black bears and elk produce whoops, growls, screams and chatter at night, and recorded calls are routinely mistaken for "Bigfoot" when the source is unseen. |
| Perception, memory or mind | 18% | Finding "language structure" in noisy animal or human sounds is a well-known pattern-seeking effect; the linguist’s analysis was not published or tested blind. |
| A hoax or fabrication | 15% | The tapes were made at a private hunting camp, never by an independent party, and parts sound speeded or edited; people mimicking calls, or altering tape speed, would produce the "language-like" pitch and pacing claimed. |
| Undetermined | 15% | The share the reading had given to fabrication on doubt rather than evidence: the record does not settle it either way. |
| An unknown or out-of-place animal | 9% | If an undescribed primate existed in the Sierra it might vocalise like this, but no body, bone or DNA has ever been found for one in North America. |
| A cultural story | 7% | The recordings became part of the Bigfoot canon through books and lectures, gaining weight with each retelling. |
| Genuinely anomalous | 2% | Sounds alone cannot establish anything beyond science; known sources and human mimicry cover them. |
Official position: No official investigation; mainstream scientists attribute such recordings to known animals or human mimicry.