Inspiring Bat Conservation Through Photos

4/9/2021

By Teresa Nichta

The Bat Scan Project provides photo documentation, enabling a growing number of conservation projects and exhibits worldwide to share the values of bats. These photos are also heavily used in children’s books, school reports, and in both scientific and popular publications. For example, the Smithsonian’s book, BATS: An Illustrated Guide to All Species, exclusively relied on nearly 400 of Merlin’s photos.

We’re delighted to share a few highlights from recent use.

A Mexican long-tongued bat (Choeronycteris mexicana) pollinating agave flowers (Agave palmeri).
A California leaf-nosed bat (Macrotus californicus) catching a cricket.
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Severe Weather Takes Heavy Toll in Texas

By Merlin Tuttle
3/2/21

Given overall warming trends, we weren’t surprised to see some 70 to 80° F days in January and February of 2021. But that hardly tells the full story!

Beginning on February 10th, historically low temperatures were recorded across Texas. For eight consecutive days (February 10–18), the temperature hovered between 37° and 9° F with six inches of snow on the ground in Austin, Texas. The first reasonable feeding opportunity for bats likely didn’t occur before the 21st.

The last similar event occurred 32 years ago in 1989. In a 9-day period (December 16–24) the daily temperature ranged from 51 to 4° F but remained below freezing for only two days versus seven in 2021. Fewer people were concerned in those days, but at least hundreds of killed bats were reported.

Brazilian free-tailed bats about to emerge from their day roost in a bridge crevice in Austin, Texas.

The recent event, Winter Storm Uri, created a disaster for overwintering Brazilian free-tailed bats (Tadarida brasiliensis). Encouraged by warming trends, more and more bats have remained in their summer roosts year-round instead of migrating south for winter. In recent years, hundreds of thousands have overwintered in bridge crevices of Central Texas, especially in the Austin area. Additionally, over the last four decades, an estimated 1,000 more annually have remained in Bracken Cave.

Unlike many other temperate-zone bats, Austin’s free-tails are not true hibernators. They do store fat in the fall and can survive for more than six weeks without feeding when roosting at 41° F. In Central Texas, they emerge and successfully feed when evening temperatures are 50° F or above, and in traditional winters they seldom would need to wait more than 10 days between feedings.

To survive for eight days with average temperatures well below freezing would be an extreme challenge. Bats have the largest surface area per volume of any warm-blooded animal, and active free-tails maintain body temperatures of roughly 102° F. Following the recent weather crisis, just warming up to go hunting was undoubtedly prohibitive for many, and it’s difficult to imagine that the insects the bats depend on for food would have been immediately abundant. Even though daytime temperatures averaged 78° F over four consecutive days beginning on February 21st.

Many concerned Austinites wondered why accumulations of dead and dying bats steadily grew through at least the 25th, despite the return to warm weather. The answer is two-fold. Many bats likely were still alive but too weakened to go hunting. Some of those may take a week or more to die. Also, those that literally froze to death could take weeks to fall from their roosting crevices. Tendons in their toes are designed to automatically lock the bats’ claws firmly to the roosting crevice until consciously released. Thus, a bat may hang in place long after its death

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Floral Adaptations to Bats May Guide Our Future

12/13/2020
By Ralph Simon

In October of 2011, Merlin, his wife Paula, and I, accompanied by National Geographic science writer Susan McGrath, began the incredibly difficult task of, for the first time, documenting a wide range of highly specialized flower adaptations to facilitate bat visitation in Costa Rica, Cuba, and Ecuador. Following three months of little sleep, red tape, floods, terrible roads, and seemingly endless searches, we finally were able to photographically document the amazing adaptations of very special plants, echo vines, old man’s beard cactus, and sea bean vines, which attract nectar bats with their acoustics (original project report).

Nectar bats must make hundreds of visits to flowers every night to find enough nectar to survive. As one can imagine, finding small flowers in the dense vegetation of a tropical forest can be challenging. But plants have evolved exceptional adaptations to help bats find their flowers. First, they provide special odors, often like garlic, cabbage, or sulfur, not attractive for humans but bats love them! Many bat-pollinated flowers have thick, waxy surfaces that reflect exceptionally strong echoes, helping bats use echolocation to find them from greater distances.

A few flowers even provide conspicuous echo-reflectors to help guide bats to their nectaries. These reflectors stand out through a wide radiation pattern, which means that bats receive loud echoes audible from many directions. They basically work like an acoustic cat’s eye (retroreflector). And they also reflect a unique spectral signature, like a fingerprint, which bats can easily identify. Behavioral experiments show that if these reflectors are missing or blocked with a piece of cotton, the flowers are rarely visited by bats, demonstrating their importance.

The most specialized flowers are found in relatively stable, tropical areas. In locations where climate and associated pollinators are less predictable, many plants hedge their bets by opening at night but remaining open and receptive for some or all the following day. This serves as insurance in case bats don’t visit. The rare echo vine (Marcgravia evenia) is such a species. It grows in low abundance in some of Cuba’s densest tropical forests. Bright red, and frequently visited by hummingbirds, it was long believed to be mainly hummingbird-pollinated.

A Leache’s long-tongued bat (Monophyllus redmoni) pollinating Marcgravia evenia in Cuba, and a Cuban emerald hummingbird is getting a free meal without pollinating. The upturned leaf reflects bat echolocation, guiding their approach like airport landing lights guide pilots at night. In fact, neither insects nor hummingbirds are large enough to contact the plant’s reproductive organs, so even when they find Marcgravia flowers, they rarely achieve pollination. 

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Improving Bat Houses in America:

Nearly 40 Years of Progress and Still Learning

9/14/2020

By Merlin Tuttle

Bat houses are outstanding tools for education. When I introduced them to Americans in 1982, my primary objective was to help people overcome fear and accept bats as valuable neighbors. That goal has been vastly exceeded. Today, hundreds of thousands of American bats live in a wide variety of bat houses.

Individuals who have carefully tested local bat preferences, and adapted accordingly, are reporting close to 90 percent occupancy. Nevertheless, there is still much to be learned. And that is why we’re initiating new collaborations.

Late last month, local member, Debbie Zent, founder of Austin Batworks, reported an impressive event. Her three-chamber nursery house had been caulked, sealed, and painted inside and out, and was mounted high on a streamside ranch building—a nearly perfect combination. But to find it overflowing with occupants just days later was surprising.

This Texas Hill Country bat house became overcrowded within days by Brazilian free-tailed bats (Tadarida brasiliensis).
The house was ideally located approximately 18 feet up on a building beside a permanent creek where it receives only morning to mid-day sun.

Was this extraordinary success due to house or location quality, or were these bats simply desperate?

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Timely New Children’s Book

9/3/2020

By Merlin Tuttle

Life Upside Down

Australia’s Grey-headed flying-foxes

Leading wildlife photographer and conservationist, Doug Gimesy, has teamed up with award-winning media graphic artist, Heather Kiley, to produce an outstanding introduction to the upside-down world of grey-headed flying foxes. Through stunning photography, simple text, and eye-catching design, this book provides a timely introduction to some of the world’s most frequently misunderstood and intensely persecuted animals.

Victims of misunderstanding and mass eradication attempts, Australia’s flying foxes now survive only as tiny fractions of former numbers. Forest clearing has left them homeless and starving. Countless thousands have been killed in mass shooting campaigns, electrocution grids, and flame thrower attacks on their roosts, known as camps. Remnant survivors are now forced to live in cities where they are needlessly demonized as carriers of dreaded diseases, despite a long history of living safely with people or subjected to attempts of forced eviction with nowhere else to go. Welcomed honeybees, dogs, and especially humans are far more dangerous! Moreover, large numbers of flying foxes are essential to reforestation and the survival of much-loved animals such as koalas.

Readers of Life Upside Down will be introduced to the real world of flying foxes as safe and invaluable neighbors and learn how they can be helped. This full-color, large-format, 48-page book is available in hardcover for $19.95 at Australian Geographic or at Book Depository.  

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Costa Rica’s Bat-Friendly Hotel

3/11/20

By Paula Tuttle

Merlin and I recently spent an especially productive week promoting bat conservation at the Harmony Hotel in northwestern Costa Rica. Merlin’s lecture, introducing the many values of Costa Rican bats, attracted a large and enthusiastic audience that included both hotel guests and community members.

Thanks to the owner’s passionate commitment to a healthy, sustainable environment, the hotel is a wildlife oasis in the midst of the small town of Nosara. Wherever possible, a lush profusion of native vegetation has been restored or introduced, serving as a magnet for animals, from howler monkeys, coatis and margay cats to large iguanas and an impressive variety of bats.

We quickly recorded more than a dozen bat species, belonging to five families, and introduced them to appreciative staff and guests. In fact, the proximity of multiple species posed the biggest challenge to use of a bat detector. The hotel may soon attract even more bats, as it intends to put up bat houses.

We were especially encouraged to learn of all the hotel’s progress toward environmental sustainability while maintaining top quality. The staff were outstanding. The food was healthy and delicious, and we thoroughly enjoyed the two evenings spent introducing the owners’ family and friends to the diverse array of bats found in their own yard.

Merlin has prepared a program on Costa Rican bats for the hotel to share with guests and in local schools, and we look forward to further collaboration.   

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Thai Adventures Part 4: Khao Chong Pran

2/19/20

By Merlin Tuttle

For me, our trip highlight was the visit to the Khao Chong Pran Cave in Ratchaburi Province. Nearly 40 years ago Buddhist monks who owned the cave had asked my advice. Their monastery relied on bat guano fertilizer sales for support. But in 1981 production was plummeting. Of course, and the monks wanted to know why.

Merlin and Surapon reminiscing about their first visit to Khao Chong Pran Cave nearly 40 years earlier.

Before dawn the next morning, my then young field assistant and interpreter, Surapon Duangkhae, and I discovered poachers using large fish nets to capture bats at the cave entrance. They were selling them to local restaurants. We hired two of the poachers to help us document the extent of the problem, then advised the monks to hire a game warden to protect their bats.

Merlin answering game warden’s questions in 1989.
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Thai Adventures Part 3: Cave Bats

12/26/19

By Daniel Hargreaves

We arrived at sunset at the OurLand Nature Reserve in Kanchanaburi Province, our home for the next 5 days. We quickly set up a few mist nets and a harp trap and were rewarded with a brace of lesser false vampire bats (Megaderma spasma) and several cave nectar bats (Eonycteris spelaea). Merlin took the opportunity to show the group how to train a bat. Unfortunately, the chosen bat was unusually difficult. However, just over an hour later it eagerly permitted Merlin to approach, enticing it to drink from a syringe filled with sugar water.

The next morning, we climbed 200 steps in search of roosting bats located in two caves above a monastery occupied by Buddhist shrines.

Group climbing the steps to the cave with Kate in the lead.
Group entering cave.
Daniel Hargreaves showing the first tiny bumblebee bat to our group.

Initially, we captured a long-winged tomb bat (Taphazous longimanus) but as the group was looking at that one, I netted two bumblebee bats (Craseonycteris thonglongyai). Both were females weighing around two grams. They were delicately held by group participants while I explained the species’ anatomy, ecology, and conservation status.

Mindy excited to be holding a famously tiny bumblebee bat.
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Bat Flash! COVID-19 Coronavirus Leads to More Premature Scapegoating of Bats

By Merlin Tuttle
Updated 03/26/20

The source of human exposure to the COVID-19 virus, or as it was first called, Wuhan virus, according to the March 12th edition of The Conversation, has yet to be identified. However, in a rush to judgment, far too many public health officials and media outlets are focusing almost entirely on bats. This has been seen in multiple news sources, from CNN to Vice. Such speculation can be counterproductive, especially when acted on as fact.

Bats, despite their essential ecological and economic roles, rank among our planet’s most rapidly declining and endangered animals1. They have few defenders and are often mistakenly viewed as dangerous. People who fear bats are less tolerant and frequently kill them 2.

Fear is needlessly created when virologists emphasize potentially distant evolutionary relationships that shed little light on where and how a virus is actually transmitted to humans. Bats are currently believed to harbor more kinds of viruses than other mammals. But even if true, there is no credible documentation of higher risk of transmission3. Most viruses are innocuous or even beneficial 3,4.

Bats, like any living organism, are capable of harboring scary viruses, yet transmission is rare, typically only to humans who carelessly handle a bat that bites in self-defense, followed by failure to seek medical attention. Nipa virus, in India and Bangladesh, is acquired by drinking unpasteurized palm juice, eating unwashed fruit, or associating with sick pigs5.

For more than a decade, virologists have used increasingly sophisticated technology to disproportionately search for new viruses in colonial bats6. New viruses can be found by looking no farther than our own human bodies, and they’re all related at some level4! We’re 96 percent genetically identical to chimpanzees7.

Scientists at Singapore’s Bioinformatics Institute examined a key surface protein on the COVID-19 virus and found it just 79 percent genetically similar to SARS, noting that these viruses “are like comparing a dog and a cat.” 8 This flies in the face of widespread claims of similarity.

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Thai Adventures Part 2: Flying Foxes

1/21/20

By Daniel Hargreaves

Several hours after leaving the painted bat village, we arrived at the Wat Chantaram, Buddhist temple, in Ang Thong province. The monks protect Lyle’s flying foxes (Pteropus lylei) in the courtyard. We explained the ecology and diet of the species and how the group should approach the colony to minimize disturbance. Slowly approached, most of the bats remained calm allowing us to watch them grooming as they prepared to depart for the evening. The bats steadily increased their activity and their chattering became louder as they started to fly out in all directions, leaving the temple grounds in search of fruiting or flowering trees. As the bats were leaving, we could hear the monks chanting inside the temple providing a magical backdrop to the evening.

Lyle’s flying foxes (Pteropus lylei) in Jantraram Temple courtyard, protected by monks in Thailand.

The following morning, we headed to Bang Pahan village in search of a second Lyle’s flying fox camp (a colony roosting site). The bats had set up camp alongside the river and after several attempts we discovered a spot where we could get closer.

Our focus was on photographing these roughly four-foot wingspan bats as they flew among roost trees. These weren’t as well protected, and something had made them nervous. They had a right to be, as some had wing membranes were perforated with holes from apparent shotgun pellets. Our group looked in awe as hundreds of these flying giants took to the sky, moving farther along the river.

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