An adult yellow-bellied marmot (Marmota flaviventris) standing on a cabin porch at the Rocky Mountain Biological Lab in Gothic, CO, whistling to warn of nearby predators.
Charlie DeTar (<a href="//commons.wikimedia.org/wiki/User:Yourcelf" title="User:Yourcelf">Yourcelf</a> (<a href="//commons.wikimedia.org/wiki/User_talk:Yourcelf" title="User talk:Yourcelf"><span class="signature-talk">talk</span></a>))
<span class="int-own-work" lang="en">Own work</span>