> The contemporary rate of extinction of species is estimated at 100 to 1,000 times higher than the background extinction rate, the historically typical rate of extinction (in terms of the natural evolution of the planet); also, the current rate of extinction is 10 to 100 times higher than in any of the previous mass extinctions in the history of Earth.
> A 2018 study published in PNAS found that since the dawn of human civilization, the biomass of wild mammals has decreased by 83%.
> The World Wide Fund for Nature's 2020 Living Planet Report says that wildlife populations have declined by 68% since 1970
> A 2023 study published in Biological Reviews found that, of 70,000 monitored species, some 48% are experiencing population declines from anthropogenic pressures, whereas only 3% have increasing populations.
And finally, with regards to rats:
> Bramble Cay melomys were declared extinct in June 2016.