What is the Red List?

The IUCN Red List of Threatened Species is the most authoritative, objective and comprehensive list of animals, plants and fungi that have been assessed for their risk of extinction.


Described as the Barometer of Life, it is widely recognised as the best measure of how the world’s wildlife is faring. The first official list was published in book form in 1966, but nowadays much of the information is online, in a searchable database that is accessible to anyone.

Why is it needed?

Because it provides critical information and analyses on the status of tens of thousands of species, subspecies, varieties and even sub-populations, and the threats that they face.

This highlights the wildlife facing the highest risk of extinction and provides the necessary information for international agencies, national governments, conservation organisations and scientific institutions to prioritise their species-protection efforts.

Who compiles the list?

The Swiss-based IUCN (the International Union for Conservation of Nature) is responsible for producing the Red List, but on a day-to-day basis it is managed and compiled by the Global Species Programme Red List Unit, based in Cambridge, which draws on information from 16,000 scientists and 1,300 partner organisations in almost every country in the world.

How is conservation status assessed?

Each species is rigorously evaluated, using specified and quantifiable criteria (such as population size, rate of population decline and geographic range) with input from BirdLife International, the IUCN Species Survival Commission and many other members of the Red List partnership. Once the assessment has been independently checked for accuracy, the species is placed into one of eight official categories.

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What are the categories?

The eight categories are:

  • Extinct - no reasonable doubt that the last individual has died
  • Extinct in the Wild - known only to survive in cultivation, in captivity or as a naturalised population well outside its historic range
  • Critically Endangered - extremely high risk of extinction in the wild
  • Endangered - very high risk of extinction in the wild
  • Vulnerable - high risk of extinction in the wild
  • Near Threatened - likely to qualify for a threatened category in the future
  • Least Concern - does not qualify for a more at-risk category
  • Data Deficient - not enough data to make an assessment
  • A ninth category – Not Evaluated – is for species not yet assessed.
The Queen Alexandra's birdwing butterfly is listed as Endangered on the IUCN Red List. © WTolenaars/Getty
The Queen Alexandra's birdwing butterfly is listed as Endangered on the IUCN Red List. © WTolenaars/Getty

So what is a ‘threatened species’?

Any species that has been assessed as Critically Endangered, Endangered or Vulnerable.

Has every species been evaluated?

Sadly, no. Some 1.74 million species have been discovered and given scientific names, though the true number may exceed 10 million.


Of those, just 93,500 have been evaluated and more than 26,000 are threatened with extinction, including 41 per cent of amphibians, 34 per cent of conifers, 33 per cent of reef building corals, 25 per cent of mammals and 13 per cent of birds. Assessments are time-consuming and expensive.


Mark CarwardineZoologist, activist, author and presenter