Researchers have found that Costa's Hummingbird can enter a torpid state, with slowed heart rates and reduced body temperatures, under low ambient nighttime temperatures. The hearts of torpid Costa's Hummingbirds beat about 50 times per minute, while those of nontorpid resting Costa's Hummingbirds beat 500 to 900 times per minute.  Reference &lt;a href="<a rel="nofollow" class="external free" href="http://www.allaboutbirds.org/guide/Costas_Hummingbird/lifehistory">http://www.allaboutbirds.org/guide/Costas_Hummingbird/lifehistory</a>" rel="nofollow"&gt;www.allaboutbirds.org/guide/Costas_Hummingbird/lifehistory&lt;/a&gt;
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/32541690@N02">Alan Vernon</a>
CC BY 2.0
<a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a>: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/32541690@N02/5565498981">Male Costa's Hummingbird (Calypte costae)..... 2 of 3 in set</a>