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From tarsiers to cloud rats, scientist strives to save Philippine species

  • In this interview, Milada Rehakova shares how she and her husband rediscovered the bushy-tailed cloud rat, previously thought extinct, on Dinagat Island in 2012.
  • Rehakova is currently working with local allies to establish the first protected areas on Dinagat Island to protect the cloud rat and tarsiers among other species.
  • Rehokova is also working to save the tarsiers of Bohol from an exploitative tourist trade.

In 2012, Dr. Milada Rehakova’s research brought her back to Dinagat Island, Philippines. It was her second expedition to the island in pursuit of insights on the tarsier, but she had another rare animal in her mind too: the bushy-tailed cloud rat (Crateromys australis). The species had been presumed extinct – it hadn’t been seen in decades – but Rehakova thought it might still be around. She laughs as she tells the story of how her husband, skeptical that she’d find an extinct species, was actually the first to spot the bushy-tailed cloud rat’s brown body with its unmistakable black and white tail.

Before Rehakova’s rediscovery, the rodent had only revealed itself to science once before, in 1975. In the meantime, mining efforts have chipped away at the bushy-tailed cloud rat’s forest habitat.

“It’s a shame that there are no protected areas on Dinagat Island on the national level,” Rehakova said. “Mining companies have divided all the land and it’s just a question of time when they will start.”

Czech zoologist Milada Rehakova (second from the right) studies tarsier social behavior and vocalizations in the field. Photo by Vaclav Rehak

The 2012 encounter captured photo and video evidence of the critically-endangered animal’s existence, giving conservationists a new reason to push for more forest protections. The effort brings together Philippine and Czech teams, including a team member from the Philippine Department of Environment and Natural Resources (DENR), and Rehakova is hopeful that key areas will remain intact both for forest-dependent species and Dinagat Island locals.

“This is also important for the people, and we want to teach them, to let them know that they, they, need the forest – not just the animals, not just the cloud rat and other species that they never meet in their life and never care for – but the people are the ones who need the forest,” Rehakova said.

While the Czech-Philippine organizations map and plan protected sites on Dinagat, Rehakova’s other conservation endeavor, The Tarsius Project, educates visitors and locals in Bohol. Just a few years ago, laws allowed locals to catch wild tarsiers for tourist displays as long as owners only had two animals at a time. But tarsiers are sensitive, and Rehakova noticed that owners’ inadequate care resulted in tarsiers’ quick deaths forcing them to continue capturing from wild populations en masse. Rehakova brought the problem to the attention of the authorities, and today, authorities no longer allow such ownership.

Instead, The Tarsius Project collaborates with Habitat Bohol and other organizations to operate a visitors’ center, which includes a spacious and appropriate home for a few tarsiers, including a breeding space that saw the rare birth of a healthy captive-bred tarsier in May 2017.

The advancements on Dinagat and Bohol Islands are occuring through a whirlwind year politically for environmentalists working in the Philippines. The extensive archipelago is home to thousands of endemic species, but mining has long threatened many biodiversity hotspots in the region and the unique animals living within them. For a few months, a new DENR Secretary, Regina Lopez, inspired hope and halted mining throughout the nation in efforts to preserve the Philippines’ astounding ecological riches, including on Dinagat. But government officials voted Lopez out of office this past May, and the fate of the island remains unclear. Still, Rehakova remains optimistic that current plans for establishing protected areas will move forward in DENR offices.

Researchers are still making significant discoveries on tarsiers like last year’s finding of multiple tarsier subspecies in the Philippines. Rehakova’s own field work includes building libraries of tarsier vocalizations and seeing how they compare across different islands, which may help researchers establish the existence of even more species. And though she’s been studying the animal for almost a decade, this nocturnal animal remains so elusive and their behaviors can range so wildly, that our current knowledge of the animal is only beginning, from defining tarsier social systems, to descriptions of their play behaviors, to fighting to keep Dinagat Island’s remaining forests intact.

Dr. Milada Rehakova is collaborating with various organizations to map and establish the first nationally-recognized protected areas on Dinagat Island. Photo courtesy of Milada Rehakova.


Jacqueline Hernandez for Mongabay:
What’s your background, and how did you come to work in the Philippines?

Milada Rehakova: I have always been fascinated about animals and nature and wildlife since my childhood, so I went to study zoology. I finished my PhD in Charles University in Prague and for my diploma and dissertation I studied monkeys in India. It was my first time [doing field studies], and I really started to love it. I studied play behavior, which is still among my interests… it’s amazing. Then [in 2007] I went to the Philippines with my friend and colleague, a zoologist from university… I visited Bohol Island and I simply fell in love with tarsiers and started to plan research and conservation projects on Bohol on Philippine Tarsiers. That’s how it started. I worked in the Philippines and I went back there for field research in 2009.

Mongabay: How did that take you to Dinagat Island specifically?

Milada Rehakova: On the first visit, we traveled around several island including Bohol. And then I started to work on tarsiers; Bohol is most famous for them. But, it was already known at the time that there is a population of tarsiers on Dinagat Island that would possibly be distinct, as it was confirmed later on by an American zoologist and his colleagues. So I went to Dinagat to see the Dinagat tarsiers and search for them, and then I got to know there are cloud rats that are possibly living [there], but had not been found for several years. It just caught my interest and I started to search for the cloud rats.

I went back the first time in 2009, when I succeeded on seeing the tarsiers but not the cloud rats. I was searching for the cloud rat in 2012 when I went there for a second time with my husband. We were in close touch with William Oliver who was the leading person of the cloud rat conservation program in the Philippines, and he told us there were several expeditions looking for this animal, but unsuccessfully. So we were mainly searching among locals, asking if they saw the species, if they knew it or not. That’s the usual way you can [find] the animals, to ask people who go to the forest, who live there, and who might get [you] in touch with these animals. We hadn’t gotten much information from them, but we got lucky ourselves while sitting in the forest, searching for the tarsiers and wildlife.

Map via Tarsius Project

It was my husband who first rediscovered the cloud rat and it was quite easy to say that it really was a Dinagat cloud rat because it has a very distinct tail, black and white, so it cannot be confused with any other species.But it took us another [ten] days to get the picture and video footage to really scientifically prove that we had found this missing animal.

Mongabay: That sounds exciting!

Milada Rehakova: Yeah because it was my husband and he texted me, “I found it! It has a black and white tail.” I said, “Did you get a picture?” But he didn’t have a camera. [The camera] was with me and we were on opposite sides [of the forest]. Then it happened again a third time, and after 10 days we finally got it. It was really exciting.

Mongabay: What’s known about the cloud rat’s life history and evolution?

Milada Rehakova: They are rodents, and the [genus, Crateromys] are endemic to the Philippines. This [genus] are not found anywhere else in the world. So they live in the Philippines on several islands. There are like 13 species, 5 genera described, and just last year there were five other species described on Luzon Island, which is north of the Philippines. It’s the biggest island and has great biodiversity.

Most of the species of cloud rat live in the mountain forest there, high in the trees. That’s why they’re called cloud rats…they are always touching the clouds. So, they are hardly visible to people, except the Luzon people. The people of Luzon used to hunt them. They developed hunting techniques like smoking out tree holes and training dogs to hunt them for food or as pets.

But on other islands it’s not a tradition, so people just don’t know about this animal. They hardly meet them in the forest, which was the case of the Dinagat cloud rat. It was first seen and described in 1975 on a zoology expedition, and since that time no single animal, no single specimen had been seen scientifically. Scientists were starting to think it was extinct, but [then] we rediscovered it after 37 years.

Mongabay: Was its habitat already endangered when it was first seen in 1975?

Milada Rehakova: Yes, it was. It’s a shame that there are no protected areas on Dinagat Island on the national level. All the forests that are left there are covered by mining claims. Mining companies have divided all the land and it’s just a question of time when they will start mining. This starts with clearing all of the forest, taking out the soil and taking out the minerals. We have visited several places there where the forest still exists, usually watershed areas that are protected by the local people or the local ordinances or laws…but not on the national level.

So it was a question about what to do with the cloud rat rediscovery. It’s quite risky to publish such results because it can lead to very quick extinctions when people know, “Oh, there’s a Critically Endangered species,” and immediately want to go and collect the species. We were aware of these risks so we didn’t publish the exact locations.

I’m very, very pleased and very lucky that I’ve been contacted by a Philippine organization last year with a proposal that they want to map and establish protected areas on Dinagat Island. They invited me to join their team and help with that. That’s how I came to Dinagat Island for a third time last year.

I’ve read a bit on how authorities have helped with conservation efforts in the Philippines. I’m curious to know a bit more about how they’ve helped specifically with the bushy-tailed cloud rat?

Dinagat cloud rat. Illustration by William Oliver

Milada Rehakova: It was a local NGO [Green Mindanao] that contacted me, but they were working closely with DENR, which stands for Department of Environment and Natural Resources, a government organization. It’s good that we can work together because it’s the DENR who should really push through all the laws and change legislation. We have one team member who has joined us from the DENR. He joined us for a couple of days to get training and get to know what we are doing in the field. And now he can push our plans forward in his office. We are still in touch, so it seems they are really proceeding towards this goal and that the protected areas will be established on Dinagat Island. I’m very happy about that because, as I said, they were all covered by mining claims. They want to exclude some land as protected areas. Their hope and goal is to have the whole island mining-free. It would be great. Dinagat Island is really unique. You know, the Philippines are among the top biodiversity hotspots in the world, and Dinagat is special among the Philippine islands. It has a high rate of endemism, of species that are not found anywhere else.

Mongabay: Will you speak a bit about any of the existing effects of mining on Dinagat? What does the landscape look like now, especially the cloud rat habitat?

Milada Rehakova: It’s kind of sad to see what’s going on there, when you go out to the island and you expect to see pristine nature and beautiful forest and animals… and you instead see the worn land and destroyed habitat. A huge amount of the land is already taken out. They take out the trees, then the soil, even the rocks, so it’s a disaster in some places. We have visited the mining areas and there’s just nothing left.

The only chance is to have really protected areas. It can’t go together; if the mining company is there they just destroy everything because they need to take the soil and the minerals, so the forest is gone. And the cloud rats need the forest. The only chance for them is to stop mining in several goal areas there, and protect the forest. This is also important for the people, and we want to teach them, to let them know that they, they, need the forest – not just the animals, not just the cloud rat and other species that they never meet in their life and never care for – but the people are the ones who need the forest. They need to protect the watersheds or there will be no water.

It’s happened on several islands where they cleared all the forest and then there was no water, so then people started wondering, “Oh maybe we shouldn’t do that,” and they started planting again… but the animals are just gone, you know? Once you wipe out the species they cannot come back. That’s something that people should know; that it’s for them, as well as for all of nature.

Mongabay: How did the Czech-Philippine partnership come about?

Milada Rehakova: It started with my first visit of Dinagat in 2009. I met some great people there and visited some places and definitely wanted to come back…I wanted to search for the tarsiers and thought, “Okay, cloud rats are interesting; they’re almost extinct so why not try to find them?” I took my husband with me, and he’s a computer programmer. He didn’t believe me at first: “Oh, right, my wife is going to find an extinct species.” So we go, and then it was him who found it… (laughs), it’s a good story. So that’s how the Czech and Philippine partnership started. I found some great people who wanted to help me with conservation, who were already aware of the necessity of protection. We kept in touch and then I was contacted by the Green Mindanao organization who wanted to do the land protection,­ mapping, and establishing the protected areas, so we joined the expedition again together with my husband and with my colleague Lubomir Peske who works with me on Bohol, and was with me on Dinagat before. So that’s our team who goes to the Philippines through the years.

Mongabay: Since the DENR secretary is no longer the same person, are protections indeed still moving forward on Dinagat?

Milada Rehakova: I don’t have the very latest information. Gina Lopez was very anti-mining and she is very passionate about wildlife protection. She was really going strictly towards this goal, but apparently it was too strict for this country so she was removed. It happened when I was in the Philippines last time. I just came back in May, so I don’t know what exactly is going on now. I hope at least some of the protected areas will be established.

Mongabay: Is there any kind of resistance that environmental groups get from mining companies?

Milada Rehakova: I didn’t get in touch with mining companies that regularly. I just visited these areas in 2012, five years ago, but I’m not in touch with them directly.

Mongabay: How do the locals in Dinagat respond to the possibility of protections on the island? Do they want mining to be there for the income?

Milada Rehakova: That’s a good question. I’m very happy [that] I get news from my colleagues that the locals are really willing to participate in habitat protection. Mining brings money. That’s why it occurs there. It brings money, it employs people, it brings money for the municipalities, and this is how it occur[s]. But the people [have] started to realize that it’s not the best thing and it’s not everything just to have money. And also the money doesn’t go to all the people. It goes to just some of the politicians, basically. So there are more and more people who are aware about the need and necessity of protection of the habitat, as I said, of the watersheds, to have water for the community, to have the forest to go there and collect the firewood. Because if there is mining then they will take out all the forest and there will be no wood for the people. So they want to protect the forest, for it to be there for themselves, which is a good sign.

Mongabay: Tarsiers are obviously charismatic animals, but I was curious what is it about them that you find most interesting?

Milada Rehakova: When I first planned to start with the research, there was not much known about their social behavior [or their] social system. There are several species of tarsiers; one lives in the Philippines, the others live in Borneo, Sulawesi, and neighboring islands. Every species has a different social system. Some live in family groups, some are solitary, some have monogamous mating systems or [are] polygamous. This [social system] was unknown in the Philippine Tarsiers so that’s what we started to study. We used radiotelemetry because it’s very hard to follow the Philippine Tarsiers. The Sulawesi species is much easier. But it’s hard or even impossible to follow the Philippine Tarsiers without the radio-collaring. So we put small radio-collars around their necks and followed them with an antenna for several months and studied their home range size, habitat use, social system, even breeding and infant and mother behavior. As I told you, I’m interested in play behavior so I have recorded the play behavior for the first time in tarsiers.

Philippine tarsier. Photo courtesy of Milada Rehakova.

Mongabay: Can you tell me a bit about what play behaviors you observed?

Milada Rehakova: There are several types of play behavior. Locomotor play, social play, object play, so I’ve observed all of these like three times in the tarsiers. It’s very cute because the animal is just a couple of centimeters tall. It’s jumping up and down on the trees, playing with the leaves, and playing with the mother. They jump on the mother, they started play-fighting together with their hands and mouths. It was very quick. Then it ended, and then they were jumping again through the forest.

Mongabay: How did the tarsiers end up on different islands?

Milada Rehakova: There are now three genera of tarsiers described. One is in the Philippines, one is in Borneo, and one is in Sulawesi. These three lineages are really the most distinct. There are several species in Sulawesi within that genus. This is how the evolution went. One lineage to Borneo, one went to Sulawesi, and one in Sulawesi. And then there is greater biodiversity within Sulawesi, with several species described. There was also a recent study in the Philippines again where they discovered four lineages that [may] be distinct subspecies, or species. It depends [on] how you look at species and subspecies because they live on different islands so they can’t breed together anyway; but there are four lineages in the Philippines, which was discovered in the last year. The animals look very similar so you cannot say the color is distinct or something; they all look very similar. The most helpful tool is genetics… In Sulawesi they just used acoustic communication. Different species talk differently; they have different languages. They live in the same area, they live next to each other, but they talk differently so you can say, “Okay they don’t breed; they are different species.” These are the two most important tools in distinguishing species in such small nocturnal mammals.

Mongabay: On the website it said that vocalizations were one of the first markers of the cloud rat’s existence. Is that right?

Milada Rehakova: The cloud rat is not that vocal like tarsiers are. For tarsiers, we sit in the forest and listen for the vocalizations. And that’s how we found the cloud rat. The cloud rat was vocalizing but very [quietly], but mostly you could hear it walking through the trees. It was quite noisy, shaking the branches and making quite a bit of noise for such a nocturnal animal. In terms of studying vocalizations, we studied tarsiers in Bohol so we can describe some acoustic signals, and this can be used later for comparisons on other islands.

Mongabay: How did local authorities in Bohol help protect tarsiers on the main tourist road?

Milada Rehakova: The tourist business mainly affects the tarsiers in Bohol. Luckily, it’s not on the other islands. On Bohol it’s a severe problem because tourists want to see the tarsiers. A huge number of tourists come every day. New places were [opening] up to show [captive] tarsiers to people, and it was just a disaster. The tarsiers are very sensitive. They cannot survive in captivity very well; they need to have specific conditions. The tarsiers just died and owners just kept removing new tarsiers from the wild, of course, legally. They had a permit to own two tarsiers, so when two tarsiers died, they just went and caught more.

I thought I should do something about that. If we want to protect the species, this is maybe the biggest threat because it was really a large number of tarsiers disappearing from the forest due to this. We approached the local authorities together with the great help of our ambassador. It was good that they listened to us and really forced these places to close down and to transfer these animals to another place built specifically for them. It’s much bigger and much fewer animals inside. There are still some animals involved in this tourist business but it’s not as large a number as it was before.

Mongabay: Has conservation education also helped stop the flow of tarsiers coming out of the forest?

Milada Rehakova: That’s something that we are really focusing on. We have our local manager there and he’s very into education. He and his colleagues developed several interactive educational programs and visited elementary schools, high schools, universities, even did some trainings for teachers. More than 700 kids and teachers participated in this program. I hope that this will have some impact on their lives. We focus on the young generation to bring this knowledge to their parents as well and hopefully to change the future. We work in the areas where tarsiers are quite common, so kids know that it’s not something that lives somewhere else, but it’s something that lives behind their houses in the forest. We’ve been doing this educational work since 2009, when we got in touch with local schools and we’ve continued and developed more and more programs. We also educate visitors together with our partner organizations; we have developed a visitor center there and eco-touristic programs that can educate tourists who go for the program, and also the locals who guide them. They learn that it’s better to have protected forests because it attracts people.

The visitors’ center on Bohol Island allows tourists to see tarsiers in a safe and comfortable environment. Photo courtesy of Milada Rehakova.

Mongabay: You’ve had some recent success with breeding tarsiers in the center. Can you talk a bit about that? 

Milada Rehakova: With our partner organizations, we have developed a visitors’ park with a guided tour, garden, and eco-tour programs for the night safari in the forest with the visitor’s hall where people [are] educated about tarsiers. Then, there’s a separate place for research and conservation purposes. We have built thick enclosures planted with trees to be as natural as we can provide for the animals. We now have one pair of tarsiers, one male and one female. The first year we caught them, there was already successful mating. Unfortunately, the baby died, probably during birth. Two days after we found that dead body on the floor, so we couldn’t do anything about it. Since tarsier breeding is seasonal, we had to wait for another year: a half year for mating, and another half-year during pregnancy. The female gave birth about the same time, in the beginning of May, and the baby is still alive. It’s now two months old, so we’ve passed the most critical period. Now we are really keeping our fingers crossed that it’ll survive. This would be a huge success because there have been some captive-bred tarsiers who didn’t survive until adulthood and didn’t breed again. So we want to have this baby grow up and then hopefully breed again, which would be a great success. This would be the first time in the Philippines, in the local country and area of origin. That’s why we started breeding the tarsiers there; to have their local climate, food, and to eliminate stress from transfer.

Mongabay: At what age do they reach maturity?

Milada Rehakova: It’s not exactly known but it seems that at about two years they’re able to breed. They stay with the mother for quite a long time, almost until the next baby is born, so almost a year.

Mongabay: Anything else you’d like to add?

Milada Rehakova: Anyone can get directly involved in our program by adopting tarsiers. It’s symbolic, of course, but we welcome regular supporters to become members of our program this way. We also sell some tarsier products!

Editor’s note 8/19/17: The story was updated to clarify the recent discoveries of tarsier species in the Philippines.

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