EDGE species facts for kids
Evolutionarily Distinct and Globally Endangered (EDGE) species are amazing animals that are very special and also in great danger. They have a high 'EDGE score'. This score combines how unique a species is with how close it is to disappearing forever.
Some EDGE species, like elephants and pandas, are famous. They already get a lot of help to protect them. But many other EDGE species are not well-known. For example, the vaquita is the rarest porpoise in the world. The bumblebee bat might be the smallest mammal. And the long-beaked echidnas lay eggs! These animals are highly threatened but often forgotten.
The Zoological Society of London started the EDGE of Existence Programme in 2007. This program helps people learn about these species and raises money to save them. As of 2019, the program has helped 87 different species in over 40 countries.
Contents
What Makes a Species EDGE?
EDGE species are chosen based on two main things: how unique they are and how endangered they are.
How Unique is a Species? (Evolutionary Distinctness)
Some species are more unique than others. This is because they have been evolving on their own for a very long time. Think of the aardvark. It has very few close relatives. It has been evolving independently for millions of years.
Other animals, like the domestic dog, are quite new. They have many close relatives. We can measure how unique a species is using an 'Evolutionary Distinctness' (ED) score. This score uses a phylogeny, which is like a family tree for animals.
This "family tree" shows how species are related. It starts with a common ancestor at the bottom. All the living species are at the top, like leaves on a tree. Each branch shows how species have changed over time. A long branch with only a few species at its end means those species are very unique. They have few close relatives.
The EDGE of Existence Programme looks at ED scores for mammals, amphibians, and corals.
How Endangered is a Species? (Global Endangerment)
The 'Global Endangerment' (GE) score shows how threatened a species is. This score comes from the International Union for Conservation of Nature (IUCN). The more endangered a species is, the higher its GE score.
| Conservation status | GE score |
|---|---|
| Critically Endangered | 4 |
| Endangered | 3 |
| Vulnerable | 2 |
| Near threatened | 1 |
| Least concern | 0 |
Note: Species that are already extinct or whose status is unknown don't get an EDGE score.
Putting it Together: The EDGE Score
The EDGE score combines a species' Evolutionary Distinctness (ED) and its Global Endangerment (GE).
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This formula means that if a species becomes twice as unique (its ED doubles), its EDGE score goes up a lot. It's almost as much as if its threat level increased by one step (for example, from 'vulnerable' to 'endangered').
EDGE species are those that are very unique (have a high ED score) and are also threatened with extinction. This means they are 'critically endangered', 'endangered', or 'vulnerable'. There are about 564 EDGE mammal species. This is about 12% of all mammals!
Helping EDGE Species
The EDGE of Existence Programme focuses on specific species. They pick from the top 100 EDGE amphibians, birds, mammals, and reptiles. They also look at the top 50 sharks and rays, and the top 25 corals.
Sometimes, they also choose species that are very unique but might not be in the top rankings. 'EDGE Fellows' are people who work to save these species. They collect information about the animals. Then, they create plans to help protect them.
Here are some of the top EDGE species that the program focused on in 2019/20:
- 1. Largetooth sawfish [[Largetooth sawfish|(Pristis pristis)])
- 2. Attenborough’s long-beaked echidna (Zaglossus attenboroughi)
- 3. Chinese giant salamander (Andrias davidianus)
- 4. Green sawfish (Pristis zijsron)
- 5. Purple frog (Nasikabatrachus sahyadrensis)
- 6. Seychelles palm frog (Sooglossus pipilodryas)
- 7. Thomasset's Seychelles frogs (Sooglossus thomasseti)
- 8. Hispaniolan solenodon (Solenodon paradoxus)
- 9. Chinese crocodile lizard (Shinisaurus crocodilurus)
- 10. Bengal florican (Houbaropsis bengalensis)
- 11. Black rhinoceros (Diceros bicornis)
- 12. Mountainous star coral (Orbicella faveolata)
- 13. Ganges river dolphin (Platanista gangetica)
- 14. Bactrian camel (Camelus ferus)
- 15. Philippine eagle (Pithecophaga jefferyi)
- 16. Northern Darwin’s frog (Rhinoderma rufum)
- 17. Hawksbill turtle (Eretmochelys imbricata)
- 18. Gharial (Gavialis gangeticus)
- 19. Chinese pangolin (Manis pentadactyla)
- 20. Togo slippery frog (Conraua derooi)
