Two tiny robots may be the smallest, lightest, and fastest fully functional micro-robots ever created, researchers report.

A new study clarifies the relationship between temperatures and changes in the size of the body parts of animals.

Nicknamed "water bears," tardigrades are only .02 inches long, but walk like animals 500,000 times their size. But why did they ever evolve to walk at all?

Living in urban areas is causing many mammals to grow bigger. Lots of available food in areas packed with people may explain why.

New research "develops a general theory to study the extraordinary diversity of life using simple rules common to all species."

Blue whale hearts work at extremes—from just 2 beats per minute when diving up to a maximum of 37 beats per minute at the ocean surface.

If your neighbors' houses are bigger than yours, you may be less likely to feel satisfied with your own home, researchers say.