Top 100 Countries by Wild Mammal Species Richness, 2025

Where the world’s wild mammal diversity is concentrated in the latest country-level data

Wild mammal species richness measures how many living wild mammal species are recorded within a country’s borders. It is a diversity indicator, not a count of individual animals, and it does not tell us whether those species are secure, abundant, or well protected. Countries rank highly when they combine warm and productive climates, strong habitat variety, mountain systems, forests, long ecological gradients, and enough evolutionary time for many mammal lineages to accumulate or persist.

The ranking is based on the ASM Mammal Diversity Database country table, using living wild mammal species recorded for each country. The source separates the Democratic Republic of the Congo from the Republic of the Congo, excludes widespread and domesticated species, and reflects the current taxonomic treatment used by the database.

Last updated: April 16, 2026. Data snapshot: ASM Mammal Diversity Database v2.4.

The main table keeps sovereign states only, so territories and dependencies are not mixed into the country ranking.

Top 10 countries by wild mammal species richness

Methodology

The ranking is based on the ASM Mammal Diversity Database country table. The database is harmonised at the taxonomic and geographic level and explicitly excludes widespread and domesticated species from the country-level counts used here.

This is not a frozen annual census in the way a macroeconomic table might be. Country totals can move when accepted taxonomy changes, when species are split or lumped, or when country-occurrence coding is corrected. The ranking should therefore be read as the latest available country-level snapshot.

Another methodological point is country labeling. A ranking stops being trustworthy the moment it merges or blurs separate states. “Congo” is not a usable top-table entry in a serious article because the current source distinguishes Democratic Republic of the Congo from Republic of the Congo and gives them very different totals.

Key insights

The ranking shows that wild mammal richness is concentrated above all in tropical and subtropical systems with strong habitat variety: the Amazon–Andes complex, the Congo Basin, Southeast Asian archipelagos, and ecotonal states such as Mexico. The upper end of the table is therefore not a list of simply “large countries,” but a list of countries where climate, terrain, forest systems, and long-term evolutionary stability repeatedly created opportunities for diversification.

It also shows why raw area is an incomplete guide. Russia and Canada are immense, yet they sit well below the tropical leaders because colder and drier systems support fewer mammal lineages overall. By contrast, Ecuador reaches the top ten despite its much smaller territory because Andes–Amazon overlap creates enormous ecological turnover inside a compact national frame.

What this means for the reader

Used properly, this ranking is a map of concentration, not a moral scoreboard. It helps readers see where decisions on forests, infrastructure, hunting control, and protected-area design can affect a very large share of the world’s mammal diversity. It also helps separate real biodiversity analysis from generic “megadiversity” talk by showing which countries actually sit in the highest current tier.

It should not be used alone. A country can rank high in richness and still be losing habitat quickly. To judge urgency, the ranking should be read next to endemism, threat status, and land-use pressure.

Country table and scale comparison

The full ranking makes one thing plain: mammal richness is concentrated in a relatively narrow group of tropical and structurally diverse countries. The controls help readers search by country, compare regions, and move between the complete list and shorter top-tier views.

How to interpret the ranking without flattening the biology

A species-richness ranking is valuable precisely because it does one narrow job well: it shows where many mammal species are concentrated at country scale. Problems begin when readers ask it to do jobs it cannot do. It does not tell us how many of those species are endemic, how many are threatened, whether habitats remain intact, or whether a country is managing biodiversity well. Those questions require other indicators.

The current Top 100 still gives a strong analytical picture. The upper end is dominated by tropical and subtropical systems with repeated habitat turnover: the Southeast Asian archipelagos, the Amazon–Andes corridor, the Congo Basin, and ecotonal states such as Mexico. That is why countries with far smaller territory can outrank much larger cold or arid states. Area matters, but ecological structure matters more.

This is also why the ranking has policy value. The countries high in this table are not merely “interesting for biodiversity.” They are countries where land-use change, forest loss, hunting pressure, road expansion, mining, and infrastructure corridors can affect a disproportionate share of global mammal diversity. In that sense, the ranking works best as a concentration map of global responsibility.