Understanding Threatened Species: The Complete Guide

SpeciesRadar tracks 55,738 threatened species worldwide, drawn from the IUCN Red List and 18,000+ national assessments. This guide explains how the categories work, what the data actually shows, and where to find the answer to any species-level question.

Species tracked
55,738
Threatened (CR/EN/VU)
55,738
27% of the catalogue
Critically Endangered
12,717
Extinct in the Wild
0
captive populations only

What "threatened" actually means

A species is "threatened" when the International Union for Conservation of Nature (IUCN) Red List classifies it as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU). The three categories sit on a sliding scale of extinction probability over a defined window — a CR listing means at least a 50% chance of extinction in ten years or three generations; EN means at least 20% in twenty years or five generations; VU means at least 10% in a hundred years.

SpeciesRadar currently catalogues 55,738 species across the three categories: 12,717 Critically Endangered, 21,904 Endangered, and 21,117 Vulnerable. Add the 0 Extinct in the Wild species — survival now restricted to captivity — and the at-risk total climbs further.

The countries carrying the burden

Threat is not evenly distributed. A handful of countries — concentrated in the tropics, on islands, or in long-isolated landmasses — host a disproportionate share of the world's threatened species. The table below lists the ten with the highest counts in our database.

CountryThreatenedCritically Endangered
Madagascar3,987717
Mexico2,656524
Indonesia2,607473
United States2,542699
Colombia2,338514
China2,130404
Malaya2,075329
England (SE-England); Denmark; Netherlands; Belgium; Germany (Baden-Württemberg [I], Hessen [I], Mecklenburg-Vorpommern, Niedersachsen, Schleswig-Holstein, Sachsen-Anhalt, Thüringen); Poland; France; Romania; Bulgaria; Estonia; E-European Russia; W-European Russia; Moldova; Ukraine; Crimea; Siberia (Altai, W-Siberia); Kazakhstan; Turkmenistan; Uzbekistan; Northern Caucasus; Georgia [Caucasus]; Azerbaijan (Talysh)2,074361

Why the global count keeps rising

Two forces push the count up. First, the IUCN keeps assessing more species — each new release adds groups previously absent (fungi, molluscs, deep-sea fish) and many enter at threatened categories straight away because they were always rare. Second, real-world declines move species across boundaries: a Vulnerable species becomes Endangered as habitat shrinks; an Endangered species becomes Critically Endangered after a crash. Cross-referencing each global assessment with the corresponding national red list is where SpeciesRadar adds the most value — a Vulnerable global rating can mask a Critically Endangered national reality.

How to use this catalogue

Every species in our database has its own dashboard: IUCN category, population trend, threat record, distribution, and protected-area coverage. Start with a search on /species or explore by country at /countries. For the methodology behind each computed figure, see /methodology.

Data sourced from SpeciesRadar (speciesradar.org), drawing on IUCN Red List 2025-2, GBIF, and national red list assessments from 200+ countries. See our Methodology for how each figure is computed.

Articles in this series

New posts in the Threatened Species cluster are added here automatically.

  • When National Red Lists Diverge

    Imagine a bird that the world considers only moderately at risk — but in the one country where it actually breeds, it is sliding toward oblivion. This is not a

    Read article →

Frequently asked questions

How many species are threatened with extinction?
SpeciesRadar tracks 55,738 threatened species across IUCN's three at-risk categories: 12,717 Critically Endangered, 21,904 Endangered, and 21,117 Vulnerable. The figures are drawn from the IUCN Red List 2025-2 and refreshed against each Red List update.
What does it mean for a species to be Critically Endangered?
Critically Endangered (CR) is the IUCN's highest at-risk category for living species — meeting at least one of five quantitative criteria including population reduction of 80% over three generations, or a wild population of fewer than 50 mature individuals. SpeciesRadar lists 12,717 CR species today.
Which country has the most threatened species?
Madagascar leads with 3,987 threatened species, followed by Mexico, Indonesia, United States. The full ranking and per-country dashboards are at /countries.