Bats

One of the primary reasons to gate a cave or mine is to protect bats. From a few solitary bats to colonies of millions, many caves and mines offer optimum habitat for these unique animals. Bats often choose these sites because of stable temperatures and roost safety. Some bats will choose cold winter sites where they let their bodies drop into a cold stupor state that conserves their body fat throughout the winter. In the summer months some bats will look for sites where the temperature is high so they can establish maturnity roosts to rear their young. Since these sites are often caves and mines the bats are well protected from the weather, as well as predation from other animals.

Many people wonder why we go to such lengths to protect bats. One of the best reasons is that bats eat huge amounts of insects. Some species of bats will eat half their body weight in insects in a single night. With some bat colonies numbering in the millions of bats, this results in a huge reduction of insects thus helping to protect farmer's crops. In areas around large human populations, bats play a significant role in reducing mosquito populations, thereby controlling mosquito borne illnesses. In some areas such as the Desert Southwest, bats play a critical role in pollinating cactus and other flowering plants.

When gating mines and caves we start by looking at what species of bat is actively using that site, so that we can build the best gate for that species. Most bats are very agile flyers and have no problem flying through the bars of a gate. We normally build all our gates with gaps of 5 3/4 inch spacing between the bars of the gate. This space is large enough for large bats to fly through, but small enough that a human can not enter the site. Some bat such as Mexican Freetail bats are very fast flyers and prefer flyover gates. And sometimes the gate design will be effected by the size of the colony, or the physical configuration of the site. The important point is that each site is different, so we try to look at all aspects of the project and create the best solution for that specific site.

Bat flying through a cave gate.