It can be tough to keep track of all the animals that are endangered and threatened these days. For starters, there are a lot of them: The IUCN estimates upwards of 16,000 species are threatened worldwide. And since these animals are notoriously hard to track, it’s difficult to know how endangered a particular species is at any given time.

Luckily, a program called Evolutionarily Distinct and Globally Endangered (EDGE) has come up with an interesting “Top 100” list. The animals that made the list had to be both threatened and “evolutionarily distinct":

”Each species is given an 'Evolutionary Distinctiveness' (ED) score, which is calculated from a family tree or phylogeny. In the phylogeny below, species A would have a higher ED score than either species B or C - it represents a branch rather than a twig on the tree of life. If species A were to go extinct, there would be no similar species left on the planet and a disproportionate amount of unique evolutionary history would be lost forever.

From the undeniably adorable to the so-ugly-it's-cute, the animals on the list make a pretty good case for protection.

One caveat: although we here at Plenty appreciate EDGE’s goal of protecting species that are evolutionary distinct, we’d like to point out that there are many less exotic species that need help, too. We don’t imagine that the Kentucky cave shrimp, for example, gets too many photo ops.

Story by Kiera Butler. This article originally appeared in Plenty in January 2007.

Copyright Environ Press 2007