Asklemmy

The entomology book Life on a Little Known Planet taught me that bebugs mate via "traumatic insemination". The female has no opening, so the male pierces the exoskeleton and the wound later heals over -- all of which allows entomologoists to count the number of times a female has mated by the number of scars on their abdomen.

the roslagsbanan commuter rail is the only actively used 2 ft 11 ^3^⁄~32~ in railway in the world.

...honestly, with a wikipedia article that extensive it hardly qualifies as "obscure".

Most military simulation databases have a classified and unclassified version. In the unclassified database a spefic russian apc is usually set to be indestructable.

It's used for a quick test when setting up a federated sim. Drop one in the sim and trigger a detonation at the location. It should either be destroyed or not in all the instances.

Opossums have 13 nipples

Living at high altitude for long periods of time can cause a disease that is otherwise most associated with cocaine and meth.

Pulmonary Arterial Hypertension has some weird causes, but it seems that high altitude and having to work for enough oxygen can cause the body to revolt.

There are no extant recordings of George Orwell's voice

The tiniest park in the USA is located on a city street corner in Portland, Oregon. Mill Ends Park

Edit: I fell down a rabbit hole. Corrected myself having posted it originally as “world’s smallest park” which is how I knew it - apparently it carried that distinction until Feb this year when a tiny space on a Japanese street (which was created in 1988) formally applied for, and was awarded the Guinness book of records title of World’s Smallest Park.

Also this one just popped into my head - the Guinness Book of Records was originally conceived as a means of settling arguments by compiling factual “records”. The original argument related to a shooting trip in England in which the Managing Director of Guinness Breweries partook, where a missed shot led to a disagreement about the fastest game bird. The realisation that arguments such as this would be commonplace, and that no resource existed to settle such matters - the niche for capturing these types of facts was identified and the book was born.

Diabetics piss has so much sugar in it that you can make high end whiskey with it.

Darwin drank tortoise piss and, according to his documentation, didn’t hate it.

Fun fact, you can, in fact, make sourdough with the yeast from a yeast infection, and bake with it.

The Leatherman Skeletool is currently available in several varieties, including the long-running standard model with an unfinished stainless steel body, a chunk of aluminum in the handle, and a 420HC semi-serrated blade, and the Skeletool CX variant with...whatever the black coating is made of, a carbon fiber chunk in the handle, and a 154CM plain blade.

When the model was first introduced, the base model had a plain blade, and the CX had a semi-serrated blade. This was swapped, as they realized first time knife buyers were more likely to see the semi-serration as a value-add, while more serious knife guys would prefer a plain blade. So you might find a very old Skeletool with a plain 420HC blade, or an old CX with a semi-serrated 154CM blade.

The smallest extant flightless bird in the world is the Inaccessible Rail.

There have been 3 observed interstellar objects that passed through our solar system: Oumuamua, Borisov and ATLAS.

Barnacles, relative to body size, have the longest penises in the world

The most common error code in Bus displays is 0x01

It is a property of GPS systems used returning a timeout

Fish mate inside of a sea cucumber's anus.