Despite making up a quarter of all mammalian species on Earth, bats remain among the least understood animals on the planet. Yet they matter enormously, to ecosystems and to us. Many bat species are voracious insect hunters, consuming up to 40% of their body weight in insects each night, they suppress pest populations on a vast scale, reducing crop damage and limiting the conditions in which insect-borne diseases thrive.

At Prince Mohammed bin Salman Royal Reserve, restoring ecosystem functionality means understanding every component of the system, including those that only emerge after dark. Since 2022, the Reserve has conducted seven dedicated bat surveys, five in consecutive spring seasons and two in autumn, with a sixth spring survey currently underway.

Josh Smithson, Senior Ecologist, explains, “The field surveys undertaken highlight the seasonal movements and distribution of bats throughout the Reserve. Understanding this is critical to our restoration efforts, as bats are keystone species providing valuable ecosystem services such as pollination and pest control”

Bat research is not straightforward. They roost in caves and narrow rock crevices, emerge only at night, and navigate in the dark with speed and precision. They are the only mammals capable of sustained powered flight, and their ability to navigate through echolocation makes them extraordinary hunters and extraordinarily difficult subjects for scientific study.

Studying the invisible

The most effective tool for capturing bats remains the mist net, a technique borrowed from ornithology. Fine silk nets originating from Japan were first adopted by mammalogists in the 1950s, and seven decades later, the method is largely unchanged, though today’s nets are made from near-invisible nylon rather than silk.

To date, the Reserve’s research team, working alongside KAUST Beacon Development and international bat specialists Taxus Ecology, has undertaken over 120 research nights, deploying mist nets across known bat flyways. Positioned between two poles and set just before dusk, the nets intercept bats as they emerge from their roosts to begin their nightly foraging.

Each captured bat is carefully removed, examined in hand, and sampled. Biometric data is recorded, including weight, finger and ear length, tragus length, tail length, and total length to ensure the definitive identification of cryptic species. DNA samples are taken from captured bats in the form of plucked fur (including follicle), 2 mm wing membrane punch, or faeces. These samples are placed into a sample vial with preservative prior to being transported to Applied Genomics in the United Kingdom for DNA analysis. The findings are then added to a global DNA database.

It was this technique that led to the Reserve recording a new bat species for Saudi Arabia, Rüppell’s bat (Vansonia rueppellii), bringing the Kingdom’s total known bat species to 32 (read more about the discovery here).

Listening to the dark

But mist nets only tell part of the story. The same extraordinary adaptation that makes bats such effective hunters, echolocation, is also what is allowing scientists to study them at scale.

Bats emit ultrasonic pulses beyond the range of human hearing, navigating and hunting by measuring the time it takes for an echo to return. Crucially, each species has a distinctive call structure, measurable by frequency, pulse duration, and the interval between pulses. The Reserve uses acoustic detectors to record these calls and convert them into data that can be visualised, measured, and matched against a reference library to identify which species produced them and where, and when.

The challenge arises when that reference library doesn’t exist. Published echolocation call data for Saudi Arabia’s bats was virtually non-existent when the Reserve’s surveys began. The team’s work has since established the most comprehensive echolocation library for the northern region of the Kingdom, making future acoustic identification across the region more accessible and accurate.

Diversity in the dark

The Reserve, covering just 1% of Saudi Arabia’s terrestrial area, supports 56% of the country’s known bat species. To date, the Reserve has recorded 18 species from 14 genera across eight families, including a species new to Saudi Arabia, Rüppell’s bat. These results increase the known bat diversity of Tabuk province from 10 to 18 species and extend the recorded global range of several species.

But this is only the beginning. The density of discovery suggests there is considerably more to uncover, and that our understanding of the Reserve’s “diversity in the dark” is only just beginning.

To read the full peer-reviewed paper, published in peer-reviewed journal, Diversity: https://www.mdpi.com/1424-2818/17/1/32 and follow us on social media for updates from the latest survey.