Local Heroes

Bats Help Save Ecosystems

By Andi Goehrs (Senior Wildlife Care Specialist at the San Diego Zoo Safari Park)*

Amazing creatures, bats come in a range of shapes and sizes big and small. They have a variety of sleeping habits, feeding habits, and anatomical features. Bats extend their arms and spread their fingers wide to fly through the sky. Many produce sound and then use their large ears or unique facial features to capture the echoes that are reflected, helping to locate their prey and navigate their environment. Fruit-eating bats gobble up seeds and then disperse them far and wide across the forest floor, where new trees will grow. Nectar-eating bats bathe in the pollen of one flower and then travel to another, pollinating each flower as they go. Insect-eating bats perform aerial acrobatics to capture insects mid-flight or even swoop to the ground and use their legs and tail membrane to scoop the insects up to their mouths. With over 1,400 species worldwide, bats make up almost one-quarter of all mammal species on Earth. They can be found on every continent except Antarctica, and each species plays a unique and important role in their ecosystem.

Homegrown Helpers

Here in San Diego County, 22 species of bats patrol the night sky at different times throughout the year. At one end of the spectrum, the tiny canyon bat weighs only 5 grams (about .18 ounces), roosts in rocky crevices, and feasts on insects. At the other end, the western mastiff bat weighs 70 grams (2.5 ounces), roosts in rocky cliffs, and hunts nocturnal insects. The pallid bat, with white fur and large ears, can be found patrolling open fields in search of scorpions and other ground-dwelling arthropods.

Several species stop in San Diego County during their migration north or south, depending on the season. The hoary bat, with its characteristic white and brown mottled fur, blends seamlessly with the trees in which they roost during the day. The Mexican long-tongued bat follows the blooming agave and seeks out cave-like structures to rest when the sun is out.

As the sun begins to set, the rolling hills and open landscape of the San Diego Zoo Safari Park and surrounding biodiversity reserves provide prime foraging habitat for as many as 17 of these wonderful bat species. Native plants attract night pollinators and other insects, which the bats feed on. Various water features throughout the grounds provide the bats with fresh drinking water, in addition to attracting nocturnal insects. The diverse landscape features provide safe roosting sites for maternal colonies to raise their pups.

Home Security Systems

Through the efforts of multiple departments, and with some outside help from the San Diego Natural History Museum, we have been working to identify the species we have at the Safari Park and striving to provide them with better resources, such as bat houses.

Over the past five years, our Construction and Maintenance team members have built bat houses of different sizes and styles to provide varying species of bats with a safe place to roost. There are currently 12 bat houses distributed throughout the Safari Park, and 5 are actively being used by different species. There are plans to put up more bat houses as we identify the places where they are needed most.

In July 2023, a trail camera was set up underneath one of these bat houses to monitor which species were inside and how many were emerging each night. The videos revealed that just after sunset, big brown bats and Mexican free-tailed bats would crawl down to the bottom of the bat house, drop out, spread their wings, and fly away into the night.

Over the last year, we have also begun using acoustic monitoring to increase our knowledge of which species we have and where they can be found. Different species produce different echolocation calls based on their foraging strategy and the habitat they live/forage in. A single species can be identified from another by analyzing recordings of these calls. By learning about which species are utilizing resources found at the Safari Park, we can better learn how to continue helping them.

These 17 species of native bats are not the only ones that can be found around the San Diego Zoo Safari Park. The Safari Park is also home to a much larger, unique species of fruit bat called the Rodrigues flying fox. This endangered species is endemic to Rodrigues Island, a small island in the Indian Ocean east of Madagascar. They can be found in the Flying Fox House, where, contrary to common beliefs about bats, they can be seen roosting in the trees, soaking up the sunshine. Due to their diet of fruit in addition to their ability to fly long distances, this species serves as a critical seed disperser on Rodrigues Island and is responsible for forest regeneration. Unlike many of their batty relatives, they do not echolocate, as it is unnecessary due to their diet of fruit. As such, they have not evolved extremely large ears or unique facial features, but rather, as their name implies, they have a face similar to a fox’s.

At bat: (clockwise from top left) A bat’s wing is made up of skin that connects the fingers, arms, legs, and sometimes even the tail; this skin can be referred to as the flight membrane. Author Andi Goehrs checks for bats inside of a bat house. A Rodrigues flying fox enjoying a piece of papaya.

Our colony has a wide age range, with the youngest bat being around 2 years old and the oldest being 20. Our wildlife care specialists offer them honeydew—their favorite fruit—from a skewer each day to help build trust with each colony member. The bats approach care specialists for the honeydew, which allows the team to assess the bats’ behavior and get a close look at their feet, wings, nails, teeth, etc. to assess their overall health. The remainder of their diet is offered high up in the trees, where they can be seen navigating the tree branches upside down or showing off their 2.5- to 3-foot wingspan and flying from one tree to another!

How to Help

Anyone can help native bats! Some ways to do your part include installing bat houses, reducing pesticide use, and turning off outdoor lights at night. If you find a bat on the ground or out during the day, contact a local wildlife rehabilitator. Due to the possibility of rabies, you should never pick up a bat with bare hands—use a cloth, bag, or glove. You can also educate yourself and others about bats native to your area, and leave dead trees in your yard if it is safe to do so. The bats could use the assistance—and so could the local ecosystem.

Another way to help support native bats is with your ShopZoo purchases! These winged mammals are popular year round but especially this October. Cast a spell with our batty new fashions, including our glow-in-the-dark Halloween Spirit Jersey, tees, winged plushies, and more! No tricks, all treats. Bring home ghoulishly good style from our Halloween collection here.

*As seen in the September/October 2024 issue of The Journal.