What 5,000 Bigfoot sighting reports say about traits over time

The question

Bigfoot's reputation includes red eyes, a knack for vanishing, woods that fall silent and a height of 7 to 10 feet. Do witnesses say these things? Has that changed over the years, or after a television programme, book or film?

This counts how often witnesses mention each trait in one large set of written reports. It says nothing about whether Bigfoot exists, only what was written down and kept. The analysis was run by an AI model (Claude) on public data, at Paul L. G. Harris's direction, on 4 October 2026. The plan was saved before the report text was scanned, apart from 30 reports read to see how witnesses phrase things.

The test

The data are 5,021 Bigfoot reports from one American organisation, as released by the TidyTuesday project on 13 September 2022. 4,983 have witness text and 4,012 a usable event date.

There are two clocks: the event year, and filing order (report number cut into five equal groups). Filing order is fairer for "when did people start saying this", because an event from 1975 may have been written down in 2015. For 335 reports whose text shows when it was written, report number and that date agree with a rank correlation of 0.78, and the estimated filing date is within a year for 60%.

Keyword rules found the traits, and 300 reports coded by hand, blind to date and rule output, checked them. Nine rules failed the pre-set standard (precision and recall both at least 0.80) and were revised once. Silence and tree structures failed again, so every hit was read by hand. A trait counts as rising or falling only if a test corrected for 24 comparisons and a second check allowing for report length agree. For television dates, the 500 reports filed just before were compared with the 500 just after, and with about 200 dummy dates.

What came out

What changed was behaviour, not size. Howls and tree structures also rose. Cloaking or vanishing, on a generous reading, is in 31 reports (0.6%) with no trend, and portals in 2, too few to say.

The rise in knocks began around 2005, years before Finding Bigfoot first aired on 29 May 2011. Knocks were 4.6% of reports filed before it and 15.4% after, but the 500 reports either side differ by only 2 points, and 53% of dummy dates show a change as large. It is a long climb, not a step. The check works: the programme's own word "squatch" went from 4 of 3,498 reports to 38 of 1,485. No trait we tested stepped up after the Missing 411 books or film, The Legend of Boggy Creek, Harry and the Hendersons or Predator.

Red eyes are in 2.4% of reports (118) once every hit was read, and they are not rising. A light was stated to be on the eyes in 56 and nearby in 6, 9 were seen from a vehicle at night, 40 said nothing about lighting, 2 were in daylight, and 5 (4.2%) said there was no light or that the eyes lit themselves. The test set in advance said reflected light would give under 10% and self-lit eyes 25% or more, so the reflected-light prediction held. Among night reports, a light source was mentioned in 68% of eye-shine reports against 35% of those never mentioning eyes.

Height is given in 1,474 reports and has not grown. But 88% are whole feet, with sevens and eights over-used and nines under-used, so these are rounded guesses.

What this does not show

These are self-selected reports to one organisation in one country, not a survey of encounters or of what witnesses saw. Red eyes acting like eye-shine in a torch beam does not show what the eyes belonged to. Rounded heights show estimating, not hoaxing.

The organisation's investigators choose, class and sometimes rewrite reports, so a change in what they ask or publish would look like a change in what witnesses say. The rise in knocks, and a fall in clear sightings from about 60% to about 40% of reports, may be partly editorial. Filing dates are estimated and the file ends in 2021. Keyword rules miss unusual wording, and counts for rare traits are floors. One reader did all the hand coding, so agreement between readers is unmeasured. Film dates from before the database were taken from the study brief and not re-checked.

Where it goes in the books

Book 8, The Ones Who Lived Beside Us. This is the lead study in the planned Interlude, "The Machine Reads Five Thousand Sightings". At 4 October 2026 the book was researched but not drafted, so no chapter text exists yet. Seven to ten feet is supported as what witnesses say. Red eyes, vanishing and silent woods are not usual features of these reports.

You can check it: the data set is public and the original reports are on the organisation's website. Pick a trait, write your counting rule down first, and compare the first and last fifth.