Monfort Bat Sanctuary, Samal Island, Philippines

Home to 1.8 million Geoffroy’s Rousette Fruit Bats

Bats in cave, Monfort Bat Sanctuary, Samal Island, Philippines
Image © Mike Aquino, licensed to

The Monfort Bat Sanctuary in the Philippines is home to 1.8 million Geoffroy’s Rousette fruit bats (Rousettus amplexicaudatus) – the largest known colony of the species in the world, according to the Guinness World Records folks.

The bats all live in a single cave – guests aren’t allowed to enter, but they can peer over bamboo railings into any of five openings where the seething masses of sleeping fruit bats can be seen coating the cave walls.

The bats have made their home in this Samal Island cave for untold generations. They used to roost all around the island until continuing human encroachment drove the flying mammals to seek refuge on the Monfort farm.

Today, this Samal Island bat sanctuary shows no signs of slowing down. A recent cave-mapping expedition found that the female bats were almost continuously pregnant, a departure from the bats’ usual seasonal gestation habits.

This, among other unusual discoveries, has led current proprietor Norma Monfort to team up with scientific teams from all around the world to transform her 57-acre farm into a serious foundation for the preservation of the Geoffroy’s Rousette.

Location of Monfort Bat Sanctuary

The Monfort bat sanctuary is located in Barangay Tambo in Babak District on the “Island Garden City of Samal” (Samal Island) near Davao City, see location on Google Maps here. The property has belonged to the Monfort family for generations; this unbroken ownership over the years may have been responsible for the property becoming a bat sanctuary.

Other bat habitats around the island were disturbed or destroyed by human encroachment, leading their residents to seek shelter in the only inviolable part of the island: the private property owned by the Monforts. The current owner, Norma Monfort, has made every effort to balance the bats’ well-being with the need for scientific study and tourist revenue.

In the past, Ms. Monfort didn’t charge admission for visitors. This changed when a Filipino TV station featured the cave on one of their shows. The resulting publicity was both good and bad for the bats: “The Department of Tourism asked me if I would allow the film crew inside,” recalls Ms. Monfort. “Afterward, when I had the cave inspected, so many baby bats had died. When the film crew was there, the bats were disturbed, and the baby bats fell to the floor of the cave.”

A One-Woman Show

After this incident, Norma Monfort changed the rules – bamboo rails were added around the cave openings, visitors now have to sit through an orientation talk before seeing the bats, and loud noises are prohibited.

Ms. Monfort has even resisted harvesting bat guano, which can sell for hundreds of dollars per kilo, for fear of scaring the bats. Still, managing the bat cave is largely a one-woman show, which Ms. Monfort rues.

“The two research students [from the previous cave-mapping expedition] will come back here to help with whatever Monfort bat caves needs, and that's good, because so far it’s only been me,” says Ms. Monfort. “It’s been so hard to do this on my own, it’s tough! I need to raise funds for infrastructure, and other stuff that people are asking me to have. We have no gift shop, no snacks or drinks! One at a time! I’m the only person in charge!”

Seeing the Cave Openings

The Monfort bat sanctuary sees about a hundred visitors a day, according to Ms. Monfort’s estimate, each paying about PHP 40 (about a dollar; read about money in the Philippines for travelers) for the privilege of seeing the bats roosting on the cave walls. Visitors enter an orientation hall, where a guide explains the significance of the bats in the local ecosystem.

After being briefed on the bats, visitors walk up a cobbled path to see the cave openings, each one surrounded by bamboo railings. The cave openings exude a strong ammonia/musk smell of bat poop (guano), but that is nothing compared to the sight of hundreds of thousands of Geoffroy’s Rousette fruit bats massed on the cave walls.

Visitors can walk around the cave openings at their leisure, seeing the bats from numerous angles. Despite their nocturnal nature, the bats roosting on the walls are not always asleep – in fact, there’s a flurry of activity among the bats even in the daytime. The bats are constantly jostling each other, changing position, fighting for space, and caring for their young. The bats’ constant shrieking echoes from the caves.

Monfort Sanctuary's Bats’ Strange Behavior

The fruit bats in the Monfort sanctuary don’t behave like other Geoffroy’s Rousettes. For starters, this species of bat normally give birth twice a year within a seasonal pattern, once between March and April and the other between August and September. (source) Not the Monfort bats – a cave-mapping expedition conducted in January 2011 found a large number of pregnant bats.

“They’re pregnant all year round. And they’re still mating!” exclaims Ms. Monfort. “And then the males are very aggressive with the babies, they’ll kill the babies so the mothers will be in heat again.”

The bats also behave strangely when they’re out of the cave. Some bats will take a dip in the nearby sea, which is “a very unusual behavior” as Ms. Monfort tells it. Another strange behavior: the male bats, coming back tipsy on fermented fruit, will linger around the nearby trees before entering the cave.

The scenic emergence of the bats from the caves at dusk, while spectacular, is not open to the public at this time – Ms. Monfort, with her limited resources, cannot afford to have a nighttime guard on hand to manage any spectators after dark.

Reaching the Monfort Bat Sanctuary

The Monfort Bat Sanctuary is located near the Samal Island coast, and is accessible by road via hired car. You can also ride a bus headed to Samal, the Samal Island City Express, from Magsaysay Park (location on Google Maps) in Davao City – the bus crosses the strait separating Samal from Davao via a Roll-On-Roll-Off ferry. From the ferry wharf on Samal, you can commission a “habal-habal”, or a motorcycle driver, to take you to the Monfort Bat Sanctuary.

To reach Norma Monfort’s Philippine Bat Conservation foundation, call +63 82 221 8925, +63 82 225 8854, +63 917 705 4295 or email:

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