EDGE species are both Evolutionarily Distinct
and Globally Endangered.



Every species is given a score according to the amount of unique evolutionary history it represents, and its conservation status. These scores are used to identify EDGE species.



Some species are more distinct than others because they represent a larger amount of unique evolution. Species like
the aardvark have few close relatives and have been evolving independently for many millions of years. Others like the domestic dog originated only recently and have many close relatives. Species uniqueness’ can be measured as an 'Evolutionary Distinctiveness' (ED) score, using a phylogeny,
or evolutionary tree. In the phylogeny below, species A has 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.

Read more about how EDGE scores are calculated.

View the top 10 Evolutionarily Distinct mammals.

Download the EDGE scientific paper.



Globally Endangered (GE) scores for each species are measured according to the IUCN Red List of Threatened Species, the world's most comprehensive assessment of the conservation status of plant and animal species. Species
which are Critically Endangered receive a higher score than less threatened species, which in turn, receive a higher score than those not currently in danger of extinction.

The two scores are then combined to produce an overall
EDGE score for each species. EDGE scores are calculated by multiplying ED and GE together. In mathematical terms, EDGE scores are an estimate of the expected loss of evolutionary history per unit time. Click here to see the top 100 EDGE mammals.

Read more about how EDGE scores are calculated or download the EDGE scientific paper.

EDGE species are species which have an above average ED score and are threatened with extinction (Critically Endangered, Endangered or Vulnerable). There are currently 521 EDGE mammal species (~12% of the total). Potential EDGE species are those with high ED scores but whose conservation status
is unclear.




Many EDGE species are not being adequately protected
by existing conservation measures. This suggests that a disproportionate amount of evolutionary history is likely to be lost in the near future. To redress this balance, we selected
10 focal species from the top 100 for which little or no conservation is currently taking place.

	Download EDGE list	|	View EDGE Species