On Aug. 25, a disastrous storm called Hurricane Harvey struck southeastern Texas. The hurricane initially developed on Aug. 17 around a group of islands near the Caribbean Sea, called the Lesser Antilles, from a tropical wave. One week later, it became a tropical storm. After it crossed the Caribbean Sea, the storm intensified until it became a full hurricane.

At its greatest intensity, Hurricane Harvey landed on the Saffir–Simpson hurricane wind scale as a Category Four hurricane. Furthermore, the deadly hurricane lasted for a period of four days, causing at least 70 deaths and extreme damages upon structures like houses and buildings.

The hurricane also found a surprising number of victims in bats that were residing in Houston, Texas. Specifically, the flooding brought on by the hurricane affected a colony of 250,000 Mexican-tailed bats. The bats lived under the Waugh Bridge, a popular tourist location in Houston. According to Amanda Lollar, founder and president of Bat World Sanctuary, a non-profit organization that rescues mistreated bats, “Normally, hurricanes and floods aren’t a big issue for bats because they roost high out of the way, so they’re not typically in jeopardy. But I don’t think anyone expected the waters to rise so high that it would get under the bridge as quickly as it did.” They also habitually fly out around dusk or even later in the night, when they are most active. Furthermore, as noted by the Houston Parks and Recreation Department, the “highest bat population at Waugh Drive is usually in August [and] September.” This accounted for the enormous number of bats affected by the hurricane.

Under the Waugh Bridge, where the bats linger, a shallow lake sits and attracts many insects for the bats to consume. Because the bats can eat thousands of insects each night, they are a useful method of controlling the insect population. Insects like mosquitoes, in particular, need to be strictly controlled because of their capabilities to carry and transmit diseases like malaria, yellow fever, zika fever, and more. With the disastrous flooding that resulted from Hurricane Harvey, many bats were trapped under the bridge and drowned, leading to unattended insect populations.

This health risk, among other reasons, led to an immediate necessity to save the drowning bats. In an effort to rescue the bats struggling to escape, dozens of people in Houston joined together to help the nocturnal mammals. The Mexican-tailed bats are unable to swim and can, at most, tread water. During the event, Houston volunteers gathered long objects that were used to allow the bats to latch on and escape. Before they could fly off, however, the bats needed to dry off and recover. On Sep. 2, an additional rescue team from Bat World Sanctuary also went to Houston to save and take in the injured bats. In the future, when they fully recuperate, the bats will be released back into the wild.