rats getting smaller and bigger

You probably hadn’t noticed — but the head shape and overall size of rodents has been changing over the past century. A University of Illinois at Chicago ecologist has tied these changes to human population density and climate change.

The finding is reported by Oliver Pergams, UIC research assistant professor of biological sciences, in the July 31 issue of PLoS One. Pergams found both increases and decreases in the 15 anatomic traits he measured, with changes as great as 50 percent over 80 years.
Science Daily, July 31 2009

thanks to Andrew Mark Harding