Paleo Slide Set: Packrat Middens: Vegetation & Climate Variability in the Southwestern United States
A midden made by the leaf-eared mouse (Phyllotis) along a river oasis in the Atacama Desert.

Packrats are not the only animals that make these rock-hard and plant-rich deposits in deserts. 
Middens also are produced by four families of rodents in South America, (including a close relative 
of the Chinchilla), a stick-nest rat in Australia, a hyrax (closest relative is an elephant) in Africa 
and the Middle East, and a rock-dwelling vole in central Asia. These middens are currently being used 
to reconstruct the former extent of vegetation in arid climates around the world and assist scientists 
in understanding the long-term dynamics of global vegetation change. 

Photo Credits:
Julio Betancourt 
U. S. Geological Survey