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Included in the IUCN Red List is the comprehensive assessment of the conservation status of the world’s 5,488 mammal species. Here you will find global summary statistics for the assessment, as well as individual species accounts including IUCN Red List threat category, range map, ecology information, and other data for every mammal species.




Figure 2. The proportion of extant (i.e., excluding Extinct) species in The IUCN Red List of Threatened Species. Version 2011.2 assessed in each category for the more comprehensively assessed groups. Taxa are ordered according to the horizontal red lines, which show the best estimate for proportion of extant species considered threatened (CR, EN, or VU). Best estimates of percentage threatened species (with lower and upper estimates) for each group are: cycads 63% (63-64%); amphibians 41% (30-56%); reef-forming corals 33% (27-44%); sharks & rays 31% (17-63%); freshwater crabs 31% (16-65%); conifers 30% (29-33%); mammals 25% (21-36%); groupers 18% (12-43%); birds 13% (12.5-13%); wrasses 5% (4-19%); lobsters <1% (0-35%). The numbers above each bar represent the total number of extant species assessed for each group. CR – Critically Endangered, EN – Endangered, VU – Vulnerable, NT – Near Threatened, DD – Data Deficient,

Figure 1. Increase in the number of species assessed for The IUCN Red List of Threatened SpeciesTM (2000–2011.2).

The numbers of species appearing in each category of threat in The IUCN Red List change each time the Red List is updated. In order to monitor the status of biodiversity, it is important to reassess species periodically. This reassessment may result in species moving into a different Red List Category for non-genuine or genuine reasons:

Non-genuine reasons

  • New information has become available since the last assessment (e.g., more recent data are available on population sizes, threatening processes, rates of decline or recovery, etc.).
  • There has been a taxonomic revision resulting in the species no longer being the same concept as it was before (e.g., it is now split into several species each with smaller ranges, population sizes, etc.; or it has been merged with other species so the range, population size, etc. are now larger than they were previously).
  • An error has been discovered in the previous assessment (e.g., the wrong information was used; the IUCN Red List Categories and Criteria were applied incorrectly; etc.).
  • The previous assessment used an older version of the IUCN Red List Categories and Criteria and the reassessment uses the current criteria which have slightly different thresholds.

Genuine reasons

  • The main threats are no longer present, or conservation measures (e.g., reintroduction, habitat protection or restoration, legal protection, harvest management, etc.) have successfully improved the status of the species enough to downlist it to a lower category of threat.
  • The main threats have continued unabated, have increased, or new threats have developed causing the status of the species to deteriorate enough to uplist it to a higher category of threat.

IUCN relies on valuable research from around the world to provide new and better information for species. Each category change on the Red List has the reasons for the change recorded, which allows us to quickly identify species that are genuinely improving or deteriorating in status. Each time the Red List is updated, a list of species that have changed category is provided along with the reasons for these changes.


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