![The Discovery Files show](https://d3dthqtvwic6y7.cloudfront.net/podcast-covers/000/014/590/small/the-discovery-files.jpg)
Summary: The balance of biodiversity within North American small-mammal communities is off balance from the last episode of global warming about 12,000 years ago that future climate change could push them past a tipping point, with repercussions up and down the food chain, say Stanford University biologists.