The whole world, and how little of it

The animal at the top of this list lives on five hectares. Not five hectares of preferred habitat within a wider range — five hectares is the whole of where it has ever been found.

This is a measurement, not a verdict. It is not the Red List, which is an assessment of risk and lives on its own page. An animal can hold a tiny range safely for a very long time. It can also lose all of it in an afternoon.

Ranked on range size in square kilometres, which 10,119 species carry. 11,453 have no figure recorded at all and cannot appear here. Mapping a range takes fieldwork across a species' whole distribution, and for over half the corpus nobody has done it.