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Bats depend on darkness. Here’s why protecting the night sky matters.

Two bats flying over a city at night.
 Credit: Photo by Yushi & Keiko Osawa.

DarkSky is proud to team up with Bat Conservation International to celebrate Bat Appreciation Day on April 17, which falls during International Dark Sky Week. 

This article was created in collaboration with Bat Conservation International and includes insights from Dr. Kristen Lear, Agave Restoration Program Director at Bat Conservation International, whose work focuses on protecting bat species and their habitats worldwide.

Together, DarkSky and Bat Conservation International are highlighting the incredible role bats play in ecosystems around the world and sharing how protecting the night from light pollution helps bats thrive.


Creatures that unite the night

Bats are among the most fascinating creatures of the night. If you have ever looked up at dusk and seen small silhouettes darting across the sky, chances are you were watching bats beginning their nightly activities.

Bats are the only mammals capable of true flight. Unlike flying squirrels, which glide, bats actively flap their wings to generate lift. Their unique wing structure has even inspired engineers designing new types of drones.

There are more than 1,500 species of bats worldwide, making them one of the most diverse groups of mammals on Earth. They live on every continent except Antarctica, from tropical rainforests to deserts, prairies, and even colder regions such as Alaska and Siberia.

Bats also live in an incredible range of habitats. Some species roost in caves, while others make homes in tree hollows, under leaves, inside rock crevices, or even in bridges and buildings in our cities.

The United States is home to the largest known bat colony in the world. At Bracken Cave near San Antonio, Texas, nearly 20 million Mexican free-tailed bats emerge each summer evening in one of the most spectacular wildlife events on the planet.

Bat drinking from flower at night with starry background.
Bats pollinate crops like bananas, cacao, and agave; spread seeds to regrow forests; and eat huge numbers of pests each night, protecting crops.

Despite their small size, bats have an enormous impact on the world we share. They help pollinate plants that produce foods like bananas, cacao (for chocolate), and agave (used to make tequila and other products). Fruit bats disperse seeds that help regenerate forests. Insect-eating bats consume massive numbers of pests every night, helping protect crops and making outdoor evenings more pleasant for people.

Across cultures and continents, bats are part of the global story of the night. Just as the stars overhead connect us all under one sky, bats are a reminder that the nighttime environment is shared across ecosystems, species, and communities worldwide.

Bats migrating through a cityscape at sunset.
The Ann W. Richards Congress Avenue Bridge in Austin, Texas, is renowned for hosting the world’s largest urban bat colony, featuring approximately 1.5 million Mexican free-tailed bats. Photo by Amanda Stronza.

The growing challenge of light pollution

While bats evolved in a naturally dark world, the nighttime environment is rapidly changing.

Artificial light at night has expanded dramatically in recent decades and continues to grow at the alarming rate of 10% globally each year. For many bat species, this can disrupt essential behaviors such as hunting, navigation, and migration.

Some bats, particularly fast-flying species, may gather near lights because insects are attracted there. But many others avoid illuminated areas entirely. Light pollution can fragment habitats by creating bright barriers that bats are reluctant to cross. For species that rely on darkness for protection from predators or for efficient hunting, even relatively small amounts of artificial light can alter their behavior.

This means that poorly designed lighting that spills into nocturnal habitats or the night sky, can unintentionally reduce access to feeding grounds, roosting areas, or migration routes.

Protecting darkness is therefore an important part of protecting bat populations and the ecosystems that depend on them.

Bat flying at night illuminated by red light.
Bats do so much to support life on Earth. Let’s do our part to protect the night and give them what they need to thrive.

Simple ways to help bats

The good news is that many of the same practices that protect the night sky also help bats and other nocturnal wildlife.

Here are a few ways anyone can help:

Create bat-friendly habitat

  • Plant native flowers that attract nighttime insects
  • Avoid pesticides
  • Add a wildlife-friendly water source

Learn more by exploring resources created by Bat Conservation International: https://www.batcon.org/about-bats/bat-gardens/

Improve outdoor lighting

Follow DarkSky’s Five Principles for Responsible Outdoor Lighting:

  • Use light only where and when it is needed
  • Keep lighting low level
  • Shield lights so they are directed downward
  • Use warm-colored light
  • Control lights with timers or motion sensors

Reducing unnecessary lighting not only restores darker skies but also creates healthier nighttime habitats for bats and other wildlife.

Learn more about responsible lighting: https://staging.darksky.org/resources/guides-and-how-tos/lighting-principles/

Celebrating the night together

Bat Appreciation Day during International Dark Sky Week is a reminder that protecting the night benefits far more than our view of the stars.

When we reduce unnecessary light, we help restore natural rhythms that bats and countless other wildlife depend on.

As we continue to celebrate this special week we encourage you to dim the lights, step outside, and look up and see if any bats make their way across your night sky.