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Helping Bats at Costa Rica’s Harmony Hotel

“Excuse me, but I can’t resist asking what you’re doing?” The question came from a curious young woman, wondering why I was six feet off one of the Harmony Hotel’s well-managed footpaths. Not just off the path but squatting low as I peered up at the underside of a drooping palm leaf. When I responded, “Would you like to see?” She was amazed to discover a family of tiny tent-making bats, each with a cute, colorful face with white eye stripes and big eyes. And like most others who questioned me, her response was, “Amazing! Bats! And they’re cute!”

The Harmony Hotel owners and staff have done an outstanding job of preserving and restoring tropical forest vegetation, which serves as an “island” of habitat for wildlife. Despite consisting of just a few acres, largely surrounded by beachfront hotels and the town of Nosara, it attracts an amazing assortment of wildlife–coatis, howler monkeys, margay cats, large iguanas, and a wide variety of birds and bats.

Thomas's fruit-eating bats (Dermanura watsoni) roosting in a “tent” cut with their teeth in a palm frond.

The most numerous mammals are bats, but being active only at night, they are seldom noticed. Two species of small fruit-eating bats take shelter beneath low-growing fan palms that they cleverly cut to form “tents” which conceal them from the dozens of passing humans and other animals, sometimes only a meter or two away. These bats are easily found once one learns to scan certain kinds of large-leaved plants for “tents.”

Palm leaf tent nicely cut by Thomas’s fruit-eating bats in the foreground with remains of an old tent behind.
Thomas's fruit-eating bats roosting in a cut palm frond.

Listening with a bat detector (a tunable device with a microphone and software combination that enables one to eavesdrop on echolocating bats) it is possible to recognize additional species at night. Because bats can adjust their calls to obtain more useful information under differing conditions some species can be difficult to identify. Nevertheless, it was still easy to tell that at least a dozen insect-eating bat species were feeding along hotel trails or drinking from the swimming pool.

Among the more interesting species heard on my detector were ghost and sac-winged bats. A northern ghost bat (Diclidurus albus) was later found hanging beneath a palm frond in a nearby valley, confirming our bat detector-based suspicions of its presence. Also, sac-winged bats survive human intrusion better than most, likely because they can hide in plain sight through effective use of camouflage. Their dark fur and uneven white lines on their backs make them difficult to see, but we heard their distinctive calls over the hotel swimming pool soon after sunset each night.

More and more guests are learning to enjoy bats, and the hotel will soon erect its first bat houses on poles in the yard. Following my most recent talk there, staff proudly demonstrated a pair of their newly built houses. Hopefully, guests will enjoy seeing more bats and face fewer mosquitos.

A northern ghost bat is well-camouflaged as it roosts beneath a palm frond. Sunlight penetrating through the frond makes the all-white bat nearly invisible from a distance. (Use magnifying tool to zoom in and see the bat above red arrow.)
A lesser sac-winged bat (Saccopteryx leptura) is also well-camouflaged as it roosts on a tree trunk.
A close up of the same northern ghost bat illuminated by flash to make it more visible. This is a rarely seen species. It is naturally white, not an albino.
Merlin Tuttle explaining bats and bat house use to guests at the Harmony Hotel in Costa Rica.
Lea Doe Haythornthwaite, (age 8), who came to the February 2023 Harmony event in Costa Rica, later told her mom that, "she wants to take over after the bat-man retires" - shown here with the Bat House Guide released in November 2022.

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Michael Lazari Karapetian

Michael Lazari Karapetian has over twenty years of investment management experience. He has a degree in business management, is a certified NBA agent, and gained early experience as a money manager for the Bank of America where he established model portfolios for high-net-worth clients. In 2003 he founded Lazari Capital Management, Inc. and Lazari Asset Management, Inc.  He is President and CIO of both and manages over a half a billion in assets. In his personal time he champions philanthropic causes. He serves on the board of Moravian College and has a strong affinity for wildlife, both funding and volunteering on behalf of endangered species.