Even some common animals are decreasing in number

Flickr: The King

Dozens of mammals on Earth have lost a third of their geographic range since the start of the Industrial Revolution, while thousands of species have seen their populations and ranges decline as well, according to a new study.

The takeaway: Even some common species, despite relatively large numbers, are at risk as their habitats shrink. Those local declines in the population can signal eventual extinction long before an animal is considered endangered — and it may be too late.

"The Earth is not only experiencing accelerated human-driven species extinctions, but also population declines," the researchers wrote.