After reading about the feet being washed up on shore, I checked the bottom of my toes; and, yes, they do have prints.
Are they unique as my fingerprints?
If there were a registry of toe prints, could the feet be identified from them?
That’s a good question, but judging from the calluses built up on my toes, it’d probably be less likely to get a set of clean prints.
Yes.
Many newborn babies get footprinted, but I don’t think there’s any central repository of them.
The only problem is the lack of central register; but if you want other body parts: in the DDR, (East Germany), the Stasi (Secret police) apparently even had a register of …
… ear prints!
Apparently the idea behind this was: a person presses their ear against the door of a house to hear if somebody is inside before they break in to rob; if the police comes along later, they can take prints from the door and match.
Biologically possible, but not enough of a database. (And not enough robbers did leave their prints that way…)
Ear shapes are quite distinctive, and can be used for pretty accurate identification. (They don’t know exactly how accurate, because there haven’t been big enough studies on this.)
They have an advantage, in that they show up clearly in photographs, unlike fingerprints.
There have been some identifications (or de-identifications) done by examining the ear shapes in photos, and comparing them to known photos of people. (One that I recall was used to debunk some of the Kennedy assassination conspiracy theories.)
Currently, most security cameras produce pictures of too low a quality for this to be effective. But I expect as better quality cameras become cheaper, you might begin to see them used in court: “Members of the jury, despite the mask he’s wearing, you can clearly see the robbers ear, and how it matches 17 unique points on this photo of the defendants ear…”.
The main advantage of fingerprints vs other biometric information is that it’s easy to accidentally leave a fingerprint at the crime scene; it can be on anything you touch. Ear and footprints (not just the shoeprints, but with the ridges) are far less likely to be found. In the days when fingerprint records were kept on cards, the space and storage requirement were so great that it made no sense duplicating the effort for something was was unlikely to be used.