We are most glad to announce that on December 15th, at the Centre Cultural de Granollers, will take place the Humans and Bats premiere! The premiere will be in the catalan original version.
We’ll see you there!
Thanks to the efforts of many people, we’ve already gone a long way in the making of this documentary! We have just opened a crowdfunding project to get the final push we need to finish it.
Watch the teaser:
Humans and Bats is a 50-minute documentary which gives a worldwide observation of an animal group that seldom leaves human societies indifferent and bears witness to the complex relations between humans and nature. Having learned about their variety, enigmatic life and global distribution allows us to tackle the need to preserve nature.
So far we have gathered the necessary footage about bat hospitals in Australia, the conflicts between vampires and farmers and their importance as pollinators in Mexico’s agriculture, the striking contrast between traditional bat consumption and bat adoration in Indonesia, and bat tourism and bats as pest controllers in Texas (USA). There are still two filming expeditions left: the impact of the largest gathering of flying foxes on Earth on human populations in Zambia, and the guano international business in Vietnam.
If you want to know more about this project browse the posts in this blog.
We’re waiting for you!
They say that when Marconi explained to his family that he wanted to try and send wireless signals over long distances they packed him off to a psychiatric institution for a check up! If we hadn’t done our background reading before, we would have been just as sceptic when Dianne Odegard from Bat Conservation International explained to us that her husband follows bat movements at Bracken Cave with the local weather radar.
We visit Dianne and Lee Mackenzie at home so that they can show us how this technological miracle works. Our visit, however, begins with the presentation of a large number of winged guests that fill several corners of their house and garden. Dianne and Lee’s lives revolve around bats and they have set up in their house a field hospital for the wounded animals they find in their area. Whilst Lee shows us the flight cage in the garden, where bats are allowed to fly before being released, Dianne feeds a free-tailed bat with maggots. Seeing it from close up, so small and frail, it is hard to imagine how it can be picked up by radar signals during its night-time flights — although the fact that it flies in the company of millions of fellow bats does make it a bit easier to understand!
The idea of using the weather radars to detect bats was developed by Thomas Kunz, probably the most brilliant and original of all bat researchers. He studied their movements and those of their prey in the atmosphere and proposed a new ecological discipline that attempts to understand the complex interaction between animal species in a constantly changing environment such as the atmosphere. He named his new discipline aeroecology.
The radar images that Lee shows us on his computer are the result of Kunz’s pioneering work. Each morning Lee enters the website of the MRMS (multi radar sensor-system), a joint venture run by a number of US research institutions that offers open access to atmospheric phenomena throughout the whole country, and which is also able to monitor bat movements. The interpretation of the images is not easy and a good dose of both practical experience and knowledge of the local climate is necessary to avoid confusing a real cloud with a ‘cloud’ of bats. In any case, Lee is able to interpret with great precision the images on the radar. He shows us how the day before a weather front from the east dragged a vast cloud of insects from agricultural regions into inland Texas. The bats made good use of this phenomenon and travelled less far than usual to feed. Just a few hours after night had fallen, the dense cloud of bats covered an area of dozens of square kilometres as it fed on this ‘manna from heaven’ that the wind had brought with it.
Lee, who insists that he is not a scientist but just a bat lover (that’s a bit hard to believe), records every day the emergence times of the various mass bat roosts in south Texas (Bracken Cave, the bridge in Austin, Frio Cave, etc.) and measures the maximum size of the various bat clouds as a means of inferring the number of bats, while at the same time taking careful measurements of environmental conditions (temperature, wind speed, atmospheric pressure, and a whole series of other variables) around each cave. His data series, rigorous and unbroken, are beginning to grow. Hi-tech popular science! The ever-present smile that is always on the face of this energetic and enthusiastic man disappears abruptly when we ask him what would happen if all the bats that he follows with such passion suddenly disappeared. “It would be a disaster – let’s just hope that it never happens.” The ‘disaster’ that Lees refers to would be a major problem for economic and public-health reasons. The new discipline of aeroecology enables us to quantify robustly the economic value of bats and the cost that their disappearance would have for farmers. The ecological service provided by bats would have to be replaced with pesticides, which would have highly negative effects on public health, and mean a bill of 700,000 dollars for the cotton farmers in south Texas alone, and of 3,700 million dollars for the USA as a whole. A price can now be put on what was once the intangible value of a small part of the natural world that surrounds us. Given the magnitude of these figures, it would not be a bad idea if the architects of our economies took it to heart.
There are places that nearly every one dreams of going some day — the Great Pyramids of Egypt and the Eiffel Tower figure high on the list of sites that many would like to visit. For bat-lovers, the list is topped without any question by Bracken Cave.
Bracken Cave is unparalleled as the largest known congregation of bats anywhere in the world. A magnificent spectacle for all — and we can’t find it! Our anxiousness grows as the afternoon draws on and we are unable to interpret the simple map we have and find the turning that leads to the cave. We’ve searched for it everywhere on the GPS but it’s not there — like it or not, on this occasion this jewel of modern technology is of no help. Bracken Cave is the Mecca of bat-loves but does not appear on the maps since its custodians make sure with great efficiency that it is not over visible. Frankly, we didn’t expect that. Given the size and importance of the cave we expected well-lit signs on the motorway between Austin to San Antonio in southern Texas, which would take us to the doors of the cave itself. After a number of false starts, out of sheer desperation we stop at a petrol station that is in theory near the cave. The person has heard of the cave but can’t tell us where it is; the second knows where it is but says it’s difficult to get there because “they got it well hidden”. Nevertheless, his directions get us there in the end in time to see the show begin.
We join a group of thirty visitors that are allowed to approach the cave today. Mylea Bayless, Director of Conservation Programmes of Bat Conservation International (BCI) is waiting to show us around. The zeal with which the BCI protects this essential site is well justified due to the pressure from housing schemes and the fact that uncontrolled visits could negatively affect the bat colony. Since they bought the cave and the surrounding land the efforts of the BCI have centred on controlling and regulating visitor access and on improving the natural surroundings. Our impression is that they have managed to fulfil both objectives very successfully. Along with Mylea there is a small group of local volunteers who accompany us on the visit and help visitors. It’s 6 o’clock in the afternoon as we reach the cave. Visitors sit on wooden benches installed by the BCI that help remind us that we have come to see what is, after all, natural show. Each bench has a metal plaque with the name of the person who paid for it. Then, Don Bergquist, a BCI volunteer who is retired, makes a long introduction, both rigorous and humorous, to the world of bats, using his voice and a few photos as his main tools. He turns what promises to be a wonderful show into an educational spectacle as well. Whilst Don is talking the first bats begin to appear and the public’s attention turns towards the entrance to the cave.
The 10-metres-long entrance to the cave is in a small depression in the ground and through it around 15 million Mexican free-tailed bats (Tadarida brasiliensis) leave every evening. They gain height in a dense frenetic spiral and fashion an impressive formation that snakes its way away towards the far horizon. The emergence can last up to 4 hours as not all bats can leave at once; thus it begins quite early, before the sun has even set. The sheer number of bats, the speed and the grace with which they fly in front of us, and the sound of their wings beating all captivate us for a while. We leave in the end when there is no more light left with which to see the many millions of bats still to leave their cave.
Once witnessed the magnitude of the spectacle, it is understandable that the BCI uses all its resources and volunteers it has to preserve this cave. The threat of a new housing project next to the land that harbours Bracken Cave has raised the alarm. Mylea explains that the buildings themselves will not directly affect the bats but will multiply exponentially the amount of contact between the bats and humans, which will have unforeseeable consequences for the cave and its occupants. The BCI has decided to avoid all conflict and Mylea is sure that the NGO will be able to raise the near 20 million dollars that it needs to buy the land and in this way prevent the building from going ahead. After having met them, we too are convinced that they will manage to raise the money.
“It’s important to hydrate!”, “Water is vital!”, are just two of the slogans shouted by Cory Roussel as he crosses the bridge on Congress Avenue, full of expectant onlookers leaning against the bridge rail. According to the US Weather Agency, in Austin, the capital of the state of Texas, temperatures only rise above 38ºC 18 days a year. It’s August and it’s one of those days and perhaps for that reason we decide to heed his words. Even though it’s already six o’clock in the afternoon, it’s still very hot and the hundreds of people on the bridge enable Cory to sell 100–200 bottles of water every evening, he tells us contentedly. This small financial help means that he can earn a living working just evenings from March to November for as long as the bats are present. Cory has grown a contagious passion for bats, and besides selling bottles he’s ever willing to educate and help the bridge’s visitors.
His business depends on a maternity roost of Mexican free-tailed bats (Tadarida brasiliensis) that occupies the fissures in this bridge over the river Colorado, and which every night attracts hundreds of people to watch the bats from every conceivable vantage point: from under and on the bridge, from the river banks or even from boats of all types on the river. The modest Texan river Colorado has not left its mark in the same way as its larger namesake has further east between the USA and Mexico, but does nevertheless still offer a unique natural spectacle of a different type. Up to 1,500,000 of these bats come to this bridge over the river Colorado. Even by day, our noses and then our ears first notice their presence as we get closer to the bridge. At dusk the bats abandon their safe shelter to fly to neighbouring agricultural areas where they will feed on the insects that fly there. They form a long procession that trails off towards the horizon and, with the last light of the day and the silhouette of the modern city centre behind them, it is a truly unreal sight. A strange but harmonious blend of neon, skyscrapers and wildlife make this a natural show that is light years from the idea of pristine nature — but it is not for that any the less attractive. The approximately 140,000 visitors that annually come to see the bats are testimony to that.
Corey’s business is a good example of how the largest urban colony of bats in the USA generates economic benefits that Bat Conservation International (BCI) calculates at 8 million dollars a year. The main benefactors are the restaurants, hotels and the transport sector. Visitors are mainly Texans, but also come from the rest of the USA and other parts of the world. Dianne Odegard, the BCI’s energetic Public Education & Training Coordinator, welcomes us fulsomely underneath the bridge and explains the history of the colony and the long fight by the BCI to save it. The work of this NGO can be summed up as a continuous series of awareness-raising efforts that since the 1980s have changed people’s perception of bats from rejection to acceptation.
Around the city of Zacatlán in the north of the state of Puebla, the landscape is strangely attractive to our eyes. It is dominated by the exuberant fleshy leaves of the agave plants or magueys, as they are called in Mexico. As we walk through the long orderly rows of plants on the Hacienda Amoltepec, we talk to Martín Pichardo, the managing director of the company Desarrollos Agropecuarios del Altiplano, who talks with passion about the cultural, economic and historical aspects of this plant and its roots in both Mexican soil and society.
The people of this region have been cultivating magueys for over 10,000 years to produce drinks, food and fibres and for a number of other uses. Around Zacatlán the magueys are basically used to produce pulque, a fermented low-alcohol drink that is well known for its high nutritional value. Other drinks distilled from maguey include mezcal and the better known tequila.
We find it hard not to look at the magueys without a certain sense of respect when Martín tells us that they produce seeds just once, when they flower at the end of their 14-year lifespans that are devoted to accumulating reserves aimed at perpetuating the species. Martín reveals that if there were no bats there would be no magueys. He adds that Mexican culture without magueys would be very different for without bats, which are responsible for pollinating the majority of the plant’s flowers, very few fertile seeds would be produced.
To the east of Zacatlán we head for the Valle de Mezquital, which harbours good populations of pollinating bats. Here Martín Pichardo and his team work to maintain the genetic diversity of the magueys by allowing natural cross-pollinating and preventing the genetic impoverishment of the maguei pulquero, the commonest form of this plant. In the other plantations that Martín Pichardo manages in more humanized areas, bats are scarce and most of the seeds are infertile. Martín explains with satisfaction that, in this case, increasing awareness amongst the rural population of the people of the Valle de Mezquital has been a key element in the protection of the bats as a means to save their agaves. Ramses Alejandro Cuatle, the vet from the Comité de Fomento y Salud Animal del Estado de Puebla who is in charge of the control of rabies in the area, confirms this: when outbreaks of rabies occur in the Valle de Mezquital, the ranchers don’t want to let on where the caves with vampires are located. They are worried that the vampire controls could harm the ‘good bats’ and they are well aware of the consequences this would have for their magueys.
Tiredness overcomes us after the over seven hours of car journey to the final ranch that the vets from the Comité de Fomento y Salud Animal del Estado de Puebla want to show us. We’ve been in Mexico for five days and once again we are spending many hours on the road and sleeping very little. Very little indeed. The rhythm of the trip makes us feel as if we could collapse at any moment but it doesn’t seem to affect Dolores Manzano, Arturo Córdova or Ramses Alejandro Cuautle. These three vets are just part of a team of 21 vets that throw life and soul into rabies control in cattle in the state of Puebla. Theirs is a job that obliges them travel to wherever a new rabies outbreak is reported and to work long nights with very little sleep.
The timetable when confronting a new rabies outbreak is full-time. By day, vaccinations, by night captures and vampire controls, and at all times, awareness raising amongst the people who live in the affected areas. The work calendar is equally full: holidays only exist if the outbreak has been brought under control and no others are reported. Halfway to our destination we head for the city of Puebla to meet Roberto Ramírez, the director of the Comité. This organization has an enormous responsibility: to protect the health of cattle throughout the whole of the State of Puebla and to foment stock rearing. Confidence and respect for its workers are the keys that enable this organization to keep up with the demands that this onerous job puts on them.
The vets have to work in close contact with the ranchers and inhabitants of rural areas, and are generally welcomed by all given that the death of even just a few cattle can completely upset the finances of a small family ranch. They help resolve a problem that emerged in Mexico during the 1990s. Dolores Manzano explains to us that before this decade, the animals that died of rabies were not properly diagnosed and, apparently, a number of vaccination campaigns were necessary to finally convince the ranchers that now and again some of their animals were dying due to this disease.
Vaccination, vampire population control and education are the three pillars on which these vets’ work rests. The vaccination and control campaigns have drastically reduced the number of head of cattle that are affected by rabies, and have also made the local population much more aware of the risks and persuaded them to take preventative action. On our visit to a number of rural communities we witnessed the high levels of awareness that the campaign had managed to achieve.
In Chila de Sal in the far western corner of the state, Alicia Vázquez welcomes us into her modest home and explains how she was bitten by a vampire in broad daylight whilst she was washing clothes in the river. Although attacks on humans are extremely rare, Alicia was able to capture the bat and – thanks to the advice given by the Comité’s anti-rabies campaign – she took it to the local health centre. This simple act and awareness of the potential risks of a bat bite saved her life. A little further north, in the community of El Salado in the municipality of Jolalpan, an agreeable spontaneous meeting with local ranchers one evening once again underlines the positive results of the rabies awareness campaign. The local ranchers all know when they have to apply the anti-rabies treatments, how to diagnose the disease, and how to separate the vampires (the ‘bad bats’) from the others (the ‘good bats’) that play such an important part in the ecosystem by eating mosquitos, pollinating plants and dispersing seeds, as the ranchers themselves explain to us.
We find a vampire trapped in a net just after dusk. Dolores Manzano from the Comité de Fomento y Salud Animal del Estado de Puebla, an expert in the habits of these bats, explains to us that the vampires always approach along the ground when they come to attack the cattle. That explains why they lay the traps on the ground next to the enclosure where the cattle will spend the night.
This vampire was undoubtedly on its way to suck blood from one of the animals belonging to Jesús Bando, member of the Puebla Rancher’s Association. Jesús tells us that whenever they inspect the cattle they always find a number of cattle with vampire wounds. Although it is dark and it is difficult to spot the wounds by torchlight, Jesus takes us to inspect part of his herd.
Maybe it is the lack of light, or perhaps the vampire ‘problem’ is not as bad as it is sometimes made out to be, but we don’t find any recent wounds on any of the 50 or so nervous cows we inspect. Nevertheless, the captured vampire and the still suppurating wound behind the ear of his horse are proof enough of the problem and a strong enough reason for Jesús to stand firm in his conviction: the populations of blood-sucking bats must be controlled. He insists that the anti-rabies vaccine does not solve all the problems caused by the vampires’ attacks since they repeatedly attack the smallest calves, taking advantage of the wounds they have already inflicted. This can weaken the animal, which may die. The vets of the Comité de Fomento y Salud Animal del Estado de Puebla that accompany us just shrug their shoulders when we ask them if they have come across this particular problem or if they know how serious it is. The little patch of jungle that, with the magical flight of the toucan, seemed so joyous by day, now takes on a much more sinister and mysterious aspect.
Whatever the truth of the matter, before releasing the bat the vets daub its back with a ‘vampiricide’ cream. Although both the ranchers and the vets are used to using it, to the more incredulous of us it resembles the product of the over-active imagination of a comic-book writer. Badly hiding our scepticism, we ask to inspect the label, on which the product’s principal active ingredient is announced as bromadiolone (“broma” meaning “joke” in Spanish), which only serves to increase our cynicism. But, as Arturo Córdova, the Comité’s vet explains, vampires are very sociable and lick each other when they mutually preen. In this way, the poison spreads through the colony and perhaps as many as a dozen bats will succumb to it. In this way, vampire populations are kept down. Bromadiolone is a very effective anticoagulant and causes death by internal bleeding. In the end, the truth dispels our initial almost comic impression of this method of bat control.
Still in the municipality of Hueytamalco and just a few kilometres away (but quite a long drive enlivened by various skids and getting stuck in the mud), we reach the neat ranch belonging to Gabriel de la Sierra, rancher and another member of the Comité. As he vaccinates some of his zebu cattle, the hardy local breed, he talks about the efforts being made by the government to ensure that the rabies prevention campaigns reach all ranchers. The cost of the vaccine, which is calculated on an annual basis, is around 10 Mexican pesos per animal (about 0.60€), while a kilo of meat is sold at about 100 pesos. Given that up to 2–3% of animals can die in a rabies outbreak, the losses that can accrue if the vaccine is not used are obvious. For Gabriel, there are no good reasons for not vaccinating cattle once the figures are worked out since, furthermore, the treatment is subsidized by the government. Making ranchers more aware and more knowledgeable is the key to the question and the Comité’s work is largely aimed at controlling rabies outbreaks and those of other infectious diseases that affect cattle herds.
We land in Mexico City to continue filming the documentary. First up is a main dish whose very name evokes a mixture of fear and fascination; an animal that in many human societies is regarded as half fantasy, half real: the vampire.
Vampires are small bats from the tropics of the Americas that resemble many others of the world’s 1,200 species of bat. Nevertheless, they have a well-known specialization: they are bloodsuckers or hemovores, that is, they feed exclusively on the blood of other animals.
We meet up with the members of the Comité de Fomento y Salud Animal del Estado de Puebla (Puebla State Committee for Improving Animal Health) and they take us to the rural areas where conflicts with vampires occur and where they do most of their work. We are lucky enough to watch how the vampires suck blood – with surprising skill – from animals that are hundreds of times bigger than they are.
The vets from the Comité have carefully set up the show and, once night has fallen and after an interminable wait made worse by our great expectations, we finally get a chance to see the vampires in action. They approach their prey by hopping agilely along the ground like frogs, their infrared vision enabling them to detect the warmest part of their victims, which is where the blood is nearest the surface. From here on, a biochemical war begins that seems like something straight out of a science fiction tale: first they lick the chosen point of attack so that the anaesthetic in their saliva deadens the animal’s skin; then they make a small insertion with their razor-sharp teeth – which the animal doesn’t even notice! – and begin to feed on the blood, which continues to flow thanks to the natural anticoagulants in the bats’ saliva. We watch as the vampires attack the feet of a horse; the bats fly off to avoid any problems every time the horse makes a movement, but then return immediately to their feasts. The whole show lasts half an hour and ends up with a sated bat, with its daily nutritional needs attended to, and a horse with a small, apparently innocuous wound on one foot.
There are three species of vampire, but only one, the common vampire Desmodus rotundus, actually feeds on mammal blood. The seriousness of their attacks are not due to the wounds they inflict on cattle but rather the infections and disease they can transmit from one victim to another. One such disease is rabies, the disease that cattle farmers and local authorities alike fear the most, and which bats can pass on with fatal consequences for their victims.
On our last night in Australia, Jenny Maclean from the Tolga Bat Hospital suggested that we head for Herberton, on the fertile Atherton plateau. The Wild River runs through the town, which lives up to the name of its river since, for the last couple of months, thousands of little red flying foxes (Pteropus scapulatus) had been roosting there.
They seem to occupy all available branches and trunks of the trees and, although we are told that there are over 100,000 bats in the colony, once there we realize that it would be an impossible task to count all the bats that roost there. Their mobility and the sheer size of their ‘camps’, the name given to their roosts, means that nobody has any idea of how many flying foxes there are in Australia nor of the trends occurring in their populations.
We admire and film the sight whilst vehicles and pedestrians cross the bridge and pass through the colony. Some people stop to admire it, surprised to different degrees, whilst others, more used to its presence, continue on their way despite the loud noises of the bats that emanate from all sides. A couple of cars stop and make noise in an attempt to scare the bats (only moderately successfully as the noise is lost in the immensity of the colony).
The effects of the bats’ presence are visible: noise and damaged trees, which annoys many local people. The benefits are harder to pin down. Jenny Maclean skilfully fends off a question by a visitor to her hospital who queries the need to preserve these creatures by saying “If over 100,000 nectar-eating bats that pollinate plants have been in our area for the last couple of months, where they obviously find enough nectar to get by, then don’t you think that they must be providing the ecosystem with some kind of service?”
The following day in mid-afternoon our plane leaves Australia en route to Singapore. We have visited Indonesia, where the outlook is bleaker, and Australia. The TV screen in the plane shows our route, with the areas of the world where it is already night shaded out. Despite the fact that we are travelling 1,000 km/hour westwards, almost as if we didn’t want to leave daytime behind, the night inevitably catches up with us before we reach our destination. Will the race to save the world’s largest bats have the same outcome?