Habitat Shift The 'Cutest Mammal Of All' Is On The Move: Temperature Changes Cause Pika Habitat Shifts By Rachel Hager • Jan 16, 2019 National Parks Service Listen Listening... / 1:44 Listen to the audio version of this story here. A change of habitat by a small mammal is having an impact on our mountain ecosystems, and the pika is being used to help understand high elevation mountain ecosystems. Changing Habitat Killed Off Mega-Herbivores 4.5 Million Years Ago, Not Humans By Rachel Hager • Dec 17, 2018 University of Utah Listen Listening... / 1:46 Listen to the audio version of this story here. Millions of years ago there were diverse and large populations of mega-herbivores, but today there are only a few mega-herbivore species. New research reveals a new theory about the extinction of these ancient mega-herbivore species.