In 2025, more than 18,000 animal species were considered at risk of extinction, according to the International Union for Conservation of Nature (I.U.C.N.). While endangered mammals such as pandas and gorillas tend to get much of the attention, the animal class with the most species in danger is fish. This graph shows the number of species in each animal class included on the I.U.C.N.’s 2025 list. Are you surprised by the results? Why or why not?
Animal Class / Number of endangered species
Fish 4,085; Amphibians 2,930; Insects 2,680; Mollusks (e.g., snails) 2,616; Reptiles 1,859; Mammals 1,364; Birds 1,256; Others* 1,691
*Other invertebrate (spineless) animals such as crustaceans, corals, and arachnids | Source: International Union for Conservation of Nature