Bodily Oddities: a catalogue of 143 strange things the human body can do

A new website called Bodily Oddities collects 143 things the human body can do that most people never hear about, from the everyday to the genuinely rare. The project was shared on Hacker News as a “Show HN” post and is built as a browsable catalogue rather than a blog: every entry gets a short description, a label for the body region and the type of phenomenon, and an estimate of how common it is where one exists.

A catalogue built for browsing

Entries are grouped by region and kind: Brain, Eyes, Ears, Bones and Muscle, with kinds such as Variation, Perception, Reflex and Involuntary. Visitors can filter by region, kind or tag. The tags include “Try it” for things a reader can experience immediately and “Not an emergency” for oddities that alarm people but are harmless.

Things you can test on yourself

Some entries describe experiences most readers can reproduce in seconds. Ear rumbling: up to about half of all people can make a low roar inside their own head by tensing a tiny muscle in the middle ear. Look at a small red light in a dark room and two faint blue arcs curve towards your blind spot — they follow the nerve fibres of your own retina, and appeared in 94% of healthy eyes in one clinic test.

Others are stranger. Jamais vu is the opposite of déjà vu: a familiar word, face or place suddenly feels unfamiliar, and in lab studies more than half of people reported it after copying a common word about 30 times. About 1% of people are truly ambidextrous, and the single-gene story about attached and free earlobes did not hold up — a 2017 study found at least 49 genetic regions involved.

Alarming, but usually harmless

A whole tag is dedicated to experiences that feel frightening and are not. The “call of the void” — a sudden thought of jumping when you stand somewhere high, with no wish to do it — affects 43% to 60% of people and is thought to be the brain’s safety system being misread. Brain zaps, a shock-like sensation in the head that often appears when someone stops an antidepressant, are reported by 15% to 50% of those who discontinue the drugs. Benign fasciculations, small visible twitches with no weakness, turned up in about 70% of healthy clinicians in one survey. Alice in Wonderland syndrome, in which objects or body parts suddenly seem far too large or small, affects an estimated 6–7% of teenagers and passes on its own.

Where the numbers come from

Prevalence figures come with caveats, and the site keeps them attached to the entries. Prosopagnosia, or face blindness, is estimated at about 1 in 100 people to 1 in 40, depending on how it is tested. Aphantasia is put at about 1% for people with no mental images at all, while around 4% have only faint imagery or none. Estimates for the Linburg–Comstock variation, an extra tendon link tying the thumb to the index finger, range from 5% to 60% across studies.