Bats of Orange County, CA: Part 2

Updated: Mar 18

Welcome back to the 2nd part of our 2-part series on Bats in Orange County. To view the previous article check out OCH’s website. In our last conversation about bats, we introduced how many bat species there are here in Orange County and debunked some of their common myths. Here we will discuss the three most common bats in Orange County which are the Yuma Myotis, Mexican Free-Tailed Bats, and the Big Brown Bats.

Yuma Myotis

top view of Yuma Myotis Bat resting in cave. Notice the light sandy fur and narrow ears. Photo by Dan Neubaum

Yuma Myotis (Myotis yumanensis) bats are small-sized bats (averaging about 24cm in wingspan and are smaller than the palm of your hand) that live for about nine years and are known by their sandy-colored fur and dark ears, nose, and wings. These bats show the popular bat behavior of staying in caves and hanging upside down that everybody thinks of when they look at a bat. Bats hang upside down because their biological characteristics make it necessary for them to sleep in this fashion. A bat actually cannot launch itself into flight from the ground like birds can, so instead they drop down from their sleeping place allowing them to take flight. They can sometimes roost (which means a place where bats settle or congregate for rest or sleep) in caves or mines, but due to human development, their favorite places to live are underneath bridges and buildings. Originally, they roost in hollowed-out trees, but when humans started to develop further, they no longer had hollowed-out trees to nurse/roost in.

Frontal view of Yuma Myotis Bat outside of the cave. Photo by Kirk Navo

Sometimes, bachelor Yuma Myotis bats reside on cliffs, but that is a rarer sight. These bats forage insects found over the water in forested areas where there is an abundant source of water. This is getting harder for them to find, because homes and buildings are being constructed, leaving their homes in ruin. The lack of Riparian habitat is forcing them to move to more densely populated cities for food and ultimately threatens their survival.

Mexican Free-Tailed Bats

Full body view of Mexican Free-tailed bat. This bat ranges in colors of brown and has larger ears than the other two species. Photo by Janet Hurley

Mexican Free-tailed bats (Tadarida brasiliensis) are medium in size (30cm - 35cm in wingspan and about as big as the palm of your hand) and have reddish/darker brown fur and black ears, lips, and wings. A cool thing about these guys is that their tails are actually longer than their tail membranes, which some say contribute to their flight speed (see picture below for reference). These bats roost in caves and abandoned buildings near the water. The water attracts the