Bat diets vary vastly and there are some real zingers on their menu—no table manners required.
10.13.25
By Wendy K. Probst
It’s after dusk. And you’re alone in a house that backs up to 23,000 acres of dark West Virginia forest. You’ve just seen a predator on the surveillance camera moving in a blur. But you can’t quite make out their form. The movement is so fast it seems supernatural. So, you play the clip again in slow motion trying to see a face. The only sound you hear through the open window is a whip-poor-will singing its oddly redundant off-key tune in the waxing moonlight.
Cue the mysterious music . . . and the record skip. Nothing dramatic here. Just a big brown bat hunting for night-flying insects.
Big brown bats (Eptesicus fuscus) —whose range spans the U.S., Cananda, and Mexico— are one of America’s most environmentally beneficial animals and can eat one third of their weight in insects in one night. And they, like a majority of the now 1,500 known bat species, are skilled, nocturnal hunters. But bat diets vary vastly and there are some zingers on their menu that might spark the question: “Wait, bats eat what?!”
Voracious Omnivores
Some bat species go for a nutritionally balanced diet of fruits, veggies, insects, fish, amphibians, lizards, and at times (mostly unintentionally), in the case of the spectral bat and greater spear-nosed bat — other bats (stay tuned for more on that).
Cut to: Barro Colorado Island —a tiny island in the Panama Canal, also known as “Bat Island,” for good reason. The island was formed when engineers dammed the Chagres River in 1914 to create Gatun Lake, the main channel of the Panama Canal and is considered a mecca for tropical biologists. It is also home to 76 thriving species of bats. It is in this little corner of bat paradise that we find the greater spear-nosed bat (Phyllostomus hastatus). Insects are just an appetizer to these gourmands, who enjoy a large spectrum of gastronomical delights (to them) and will gulp down nearly anything smaller than them—from fruit and nectar to birds and frogs.
Expertise is needed to really dig into some of the vast and varied appetites of bats, which is where a few, very cool bat scientists weigh in to answer: What is the wildest thing you’ve ever seen a bat eat?
Enter bat detective, Teague O’Mara, also known as BCI’s Director of Conservation Evidence, who studied bats at the Smithsonian Tropical Research Institute in Panama.
Nectar Addicts
“Nectar, to me, is one of the most unusual things a bat can eat,” says Teague. “It’s mostly water — low calorie density, low in vitamins and minerals, and needs specialized anatomy or foraging strategies to feed on effectively. There’s also something about nectar that changes bat behavior — straw colored fruit bats in Africa will fly over fields full of ripe fruit to instead feed on nectar. There’s just something about it that bats love, even if it’s not the most efficient of foods.”
Pan back to the United States and Alyson Brokaw, behavioral ecologist, bat scientist, and Bat Pub contributor, who was so enthusiastic when asked “what are some surprising items on the bat menu,” that she sent a short list.
“Some of my favorite examples for things that might make people say, ‘Bats Eat What?’ include:
Scorpions
Not only do some bats eat scorpions, but two different bat species on opposite sides of the world have both evolved similar strategies for attacking and eating these potentially dangerous prey: Pallid bats (Antrozous pallidus) and Hemprich’s big-eared bat (Otonycteris hemprichii). Pallid bats are also resistant to the sting of the Arizona bark scorpion, one of the most venomous scorpions in North America. Scorpion venom works by activating voltage-gated sodium channels in cells, which is what causes pain. Pallid bats appear to have modified versions of these channels that keep the venom from binding as effectively.
Sea Lions
Or at least, sea lion blood. Common vampire bats (Desmodus rotundus) living along the rocky island of the Peruvian coast appear to feed primarily on the blood of sea lions. This data comes from both field observations and reports of bats feeding from sea lions while they sleep on the shore and from isotope analysis. Camera trap data from around the vampire bats range has also caught vampire bats in the act of feeding on tapirs, deer, giant armadillo, and even a mountain lion.
Leaves? Really?
This one may not be as exciting, but it is interesting because it’s unusual for small animals with high metabolic demands like bats to eat leaves. That’s because leaves tend to not have as much readily available energy. However, at least 8 species of Neotropical fruit bats have been reported to chew on leaves, extracting the liquid and then spitting out the rest of the leaf fibers. It’s thought these bats chew on leaves as a way to supplement their diet with missing vitamins and/or minerals that are lacking in their fruit-heavy diets.
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Next, we travel over to Brazil, where BCI’s Brazil Program Manager Jennifer Barros spends a lot of time in rainforests and caves studying the over 170 species of bats currently known to live in Brazil.
Frogs and Other Bats
“Carnivorous bats are my favorite, and I think it’s crazy to think that bats can eat other bats (I’ve seen it happening, and it’s truly impressive),” Jennifer says. “But, I think, even more surprising are the adaptations that fringed-lipped bats (Trachops cirrhosis) have for feeding on frogs. They have specialized hearing to eavesdrop on frog calls and echolocation to refine prey location, and unique salivary glands that may help neutralize toxins. On the other hand, I could also mention fishing bats. Since I don’t like eating fish (or anything from the sea or river), I don’t know how they dare do that, eww!”
Fishing Bats
Since they came up (see above, before the “eww”), a couple species of bats could be the envy of many savvy anglers. The fish-eating myotis (Myotis vivesi) and the greater bulldog bat (Noctilio leporinus) have evolved large, clawed feet that enable them to subsist mostly on fish—some can catch and gulp down as many as 30 fish in a night. These two bat species live and “fish” along the sparkling waters of the Sea of Cortez, western Pacific shores of Baja (fish-eating myotis) and Mexico through Central and South America to northern Argentina, and the Caribbean, including Cuba, Granada, and Jamaica (greater bulldog bat).
To understand more about the appetites of these fish-snatching bats, we turn again to Jennifer Barros: “What I think is interesting is that these bats can react to targets, such as a fish breaking the water’s surface, and can distinguish fish from insects based on their patterns of disappearance, so they can choose a lighter dinner (insects) or something more robust like fish.
In all these details, notably, one of the most phenomenal attributes of bat diets seems to be the complexity of adaptations or modifications that are unique to numerous bat species. Non-scientifically speaking, how bats have physically evolved and what goes on inside of their digestive systems, cells, mouths, and salivary glands seems like fodder for an epic sci-fi tale. I mean, they have been around for more than 50-million years.
Non-scientifically speaking, how bats have physically evolved and what goes on inside of their digestive systems, cells, mouths, and salivary glands seems like fodder for an epic sci-fi tale.
Back in the forests of West Virginia, where that eastern whip-poor-will is singing away. Nightjars, like the whip-poor-will and chuck-will’s-widow exist in the same nocturnal world as bats and feed almost exclusively on insects. Enter one more fun-but-weird fact. Chuck-will’s-widows have, on occasion, swallowed small bats with their large, wide-open mouths when prepping to gulp down their usual prey. So, you might wonder: What else eats bats? Our friends at the Nature Conservancy’s Cool Green Science have a delightfully dark list of answers to that question.
Wendy K. Probst is the editor of The Bat Pub, and a freelance editor and writer who has devoted her career to working with stellar conservation organizations like Bat Conservation International and the Appalachian Trail Conservancy. She is both driven and anchored by her desire to dream, create, preserve, educate, and empower others.
