To assess the conservation status of the world's land mammals, we comp
iled data on the number of total species, endemic species, recently ex
tinct species, and currently endangered species for 155 countries. Tot
al species richness was significantly correlated with territorial land
area, whereas number of endemic species was only weakly correlated wi
th both area and total number of species. The large amount of variatio
n left unexplained by species-area regressions reflects the influence
of other factors, such as latitude, topographic and habitat heterogene
ity, and historical biogeography, on species richness and especially o
n patterns of endemism. Countries of particular conservation concern,
because they have rich mammalian faunas containing many endemic specie
s, are the large islands of Australia Madagascar, Indonesia and the Ph
ilippines, as well as continental Mexico. Patterns of recent extinctio
ns and the current endangered status of species were difficult to inte
rpret, largely because of inadequate and inconsistent data. The majori
ty of officially listed endangered species are large, well known, and
popular mammals, such as primates, ungulates, and carnivores, whereas
the majority of species known to have gone recently extinct and likely
to be currently threatened are small and inconspicuous, such as roden
ts and bats. Our work not only illustrates the role of ecological, evo
lutionary, and biogeographic processes in the origin and maintenance o
f land mammal diversity it also presents the information at the level
of biogeographic regions and political units where management and poli
cy must be applied in order to slow the loss of this diversity.