Remembering Daniel

I met Daniel Bennett at a symposium of the Wildlife Conservation Society of the Philippines in 2006. At that time, I was working on my graduate studies and was doing an internship with a local environmental organization that sent me to the symposium to interview the biologists studying endangered endemic animals in the Philippines. Daniel was a leading authority on the butaan, a monitor lizard endemic to the Philippines. When my colleague and I interviewed him, I remembered how he refused to look at me. He later admitted that I made him nervous and fidgety. We ended up in the same field trip organized by the symposium and became fast friends. After the symposium, he kept in touch and bugged me to visit Polillo and the rainforests where he worked. I did and was moved by his dedication to his life’s work and his obvious love for the forests, the people, and the country. That visit strongly influenced my graduate work.

Our friendship evolved into something more, however, the relationship did not work out. But we ended up good friends for years thereafter. He often popped up online to ask me how I was doing, and whenever we were in the same city, made it a point to see me. It is hard for me to believe that I will never see him or hear from him again. I am forever grateful that our paths have crossed and my life has been infinitely enriched by him.

Below is something I wrote after my visit to Polillo. Rereading what I have written years ago brought back the feeling of awe learning about this fascinating creature. Daniel gave feedback and edited this short paper which has never been published anywhere. I thought it a fitting tribute to him to dig this out of my archives and finally share this paper.

In loving memory of Daniel Bennett.

Photo from the Daily Mail

At the 2006 WCSP with Philippine wildlife’s biggies: From left, botanist Leonard Co (who sadly passed away in 2010), rafflesia expert Julie Barcelona, and Daniel Bennett.

-=-=-=-=-=-=- 

An Enigma Called the Butaan

It is tough to find a more fitting symbol of the mystery of Philippine rainforests and the wonder of its biodiversity than the elusive butaan. In a quest to catch a glimpse of this puzzling creature, one must venture deep into the last remaining untouched forests at the heart of Polillo (1).

Mysterious Polillo

Few people, Filipinos included, have ever heard of Polillo. Even fewer people know where it is. Located right in the Philippine Sea, on the fringes of the Pacific Ocean, Polillo is separated from mainland Luzon by the Polillo Strait.

It is not surprising that not many people know of Polillo. To make the journey to Infanta, Quezon from Manila, one must take a 3-5 hour bus ride (depending on the time of day and the traffic situation) through roads that wind up and down the Sierra Madre mountain range. So dizzying is this bus ride that it is almost possible to guarantee that at least one child or baby on board will vomit during the trip. It takes another two and a half hour ferry boat ride to get to Polillo’s town center which is about 18 miles off the eastern coast of Luzon.

Even before the Spaniards took hold of Polillo in 1571, trade relations between Chinese merchants and the natives of the island already existed. The name “Polillo” is said to have originated from the Chinese words “Pu li lu” which means “island of plenty”. A Spanish friar named Padre Domingo changed this to the more Spanish-sounding name, Polillo. As with the rest of the Philippines during the early 1900s, Polillo was practically 100% forested.  At present, less than 3 km² of old-growth forest remain (2), nestled amongst coconut plantations that provide income for the island’s copra farmers. According to Philippine Census Information as of 2000, Polillo is populated by 24,105 people living in some 5,102 households. Current population is estimated to be around 50,000. Most of these people are from Bicol and many still speak the Bicolano dialect.

Polillo is as rustic as a remote rural town could be. There are practically no cars – only two or three jeeps that ply the rough roads to other barangays, but these are rendered useless during the rainy season when they become slippery with mud and are thus impassable. The port is probably the busiest place in the entire island, and that was about it. There is no electricity, except from 6 p.m. to 2 a.m. and only in Polillo town. Marketing is also a strange affair on this island. While there is a small public market in the town center, most of the local people strive to be self-sufficient by growing their own rice and vegetables and raising their own livestock. To our amusement, our host insisted on knowing what we would like to eat because she would have to hunt for ingredients from her neighbors! She insisted that the market was quite useless.

Those who have heard of Polillo know it as the “typhoon island”. Storms coming from the Pacific Ocean hit this island head-on. The people of Polillo are not so much afraid of the torrential rains as they are of the strong winds. So strong are the winds that they are able to knock down old hardwood trees and blow off rooftops. After a typhoon, people fight over which piece of galvanized iron used to be their roof!

Polillo is home to some of the Philippines’ last remaining virgin forest. For someone who is unacquainted with forests in general, I did not know how to tell where the forests actually began or where it ended. One could tell, in part, by the density of the foliage. At least in Polillo, you know that you have entered the forest when there are no coconut trees around. You also know that you have entered a virgin forest when you still see gigantic old trees whose wood is very much prized. Just to give an idea of how dense the foliage is – We heard rain coming and so quickly packed up our cameras in waterproof cases. The sound of the rain continued, growing louder, but it took some five to ten minutes before we even felt raindrops touch our skin! Even in less than pristine conditions, the forest is still remarkably dense.

Another extraordinary detail about the forests of Polillo is the presence of thorny and prickly trees, plants and vines. It is almost impossible to walk through the forest without getting your clothes hooked by the spikes, or without scratching your skin. One cannot help but wonder about the purpose of such bristles. Could it be that the plants grew thorns to protect themselves from animals that ate them for food? Could it be protection from trampling? In any case, they seem superfluous and unnecessary now, yet evolution takes an especially long time. Another evidence of the absence of big animals is the flourishing forest undergrowth. Unlike the rainforests of Malaysia and Indonesia, the rainforest floor of Polillo thrives with all kinds of ferns and shrubs and small plants.

Intriguing folklore 

For the local people of Polillo, the butaan is widely known for its notoriously delicious meat, and as such, is extensively hunted. Local people attribute the scrumptiousness of the butaan’s meat to its unique diet which consists mainly of fruits. The meat and the innards of the butaan are not malansa (loosely translated to mean “fishy” in smell or taste), unlike those of pigs and cows. One popular recipe involves melting the fat of the butaan, and stir-frying its innards and meat in the tasty oil – a certified mouth-watering treat (Maseram!). The skin of the butaan was used (although not widely or commercially) for making wallets, belts, and even the local delicacy chicharon (crispy skin).

Local people have an amusing way of talking about the size of the butaan. An ordinary conversation would go like this:

“Nakahuli ako ng butaan!” (I was able to capture a butaan!)

“Talaga? Gaano kalaki?” (Really? How big is it?)

“Ay, dalawang sako ng pili ang laman!” (Oh, its tummy contains two sacks of pili!)

The butaan eats pili nuts but does not digest the nuts completely. When people open up the butaan’s stomach, they are usually able to find a lot of pili nuts inside. The pili nuts are as prized as the butaan itself. As Christmas draws near, some local people climb up trees and search the holes where the butaan hide, and they are rewarded with piles of pili nuts.

There is a folktale that attests to the sheer strength of the butaan. Once there was a Dumagat who saw a huge butaan climbing up a big tree. This Dumagat caught the butaan by the tail. So strong was the butaan that it was able to drag the Dumagat up the tree. The Dumagat never came down and the story goes that some people sometimes see the Dumagat’s loincloth on the tree tops and that his ghost still haunts the tree.

A fascinating creature

My impression of the butaan when I first saw it up-close at Avilon Zoo is that it is a very smug, smart, and ruggedly handsome monitor lizard. Perhaps it has something to do with its characteristically slit-shaped nostril, unlike most bayawak (big lizard) that have round nostrils. The pattern on its skin is what Bennett (1995) calls “cryptic coloration”, useful for camouflage when it stays immobile in vegetation in the face of imminent threat.

Daniel Bennett of Leeds University confessed that he took interest in monitor lizards because they are large, conspicuous, and not at all shy – “perfect for a field scientist who isn’t very observant,” he says. One can catch the same lizard twice or thrice in a week. To his surprise (and consternation?), the butaan was a completely different monitor lizard. It is a terribly shy animal!

The butaan is the biggest lizard in the Philippines and also one of the largest lizards in the whole world, reaching almost a total length of 2 meters and weighing a maximum of 10.5 kilos. The butaan tends to get very big and fat as it gets older, although it must be noted that only the males get very big while the females rarely exceed 5 kilos. I remember Bennett’s first description to us, “It’s as big as a guitar!”

As if that were not fascinating enough, it is also the only truly frugivorous (fruit-eating) lizards in the whole world. Apart from the mabitang which is closely related, the butaan is the only one, out of 60 species, that eats fruits. All the other species are completely carnivorous. Fruit-eating vertebrates (ex: birds and flying foxes) almost always have wings that afford them mobility and enable them to move between food sources easily. The butaan is exceptional in this respect as it is the largest and the least mobile frugivore. How could an animal that eats fruits (and snails) get so big? Perhaps it needs fat reserves to prepare for times where fruit supplies may be unavailable for extended periods. From the evolutionary perspective, something must have happened such that one lizard from a family of carnivorous lizards evolved to be fruit-eating. Perhaps competition with other bayawak for food, plus the widespread availability of all this fruit that nobody else would eat, lead to the butaan’s frugivorous nature.

The butaan has a forked tongue like a snake. Forked tongues are useful as a supplementary means to assess the environment. The butaan can determine whether a stimulus (ex: scent of a particular fruit) is stronger on the right or the left part of its forked tongue and can act accordingly (ex: move in the direction where the scent is stronger). The butaan also has extremely long curved claws. The lower half of its body is very strong, with physically powerful hind muscles that are able to support its entire weight (3). The butaan has incredibly strong jaws, a forceful bite, and strong neck muscles. If you attempt to pull out an individual fruit from a clump of pandanus fruits, you would then begin to understand what a feat it is for a butaan to even begin the task of feeding itself!

Curious habits

Bennett has been working for over 6 years with the butaan and he has seen less than 25 individuals. Because the butaan is extremely shy, it is very difficult to count them or get an idea of how many they are in the wild. If you scare a butaan up a tree, research suggests that it will stay up there for up to 27 days. But of course, the butaan is quite comfortable up in the tree as it is an arboreal animal and spends most of its time in trees anyway. Research shows that adults spend only about 25 minutes a week on the ground. The butaan is also capable of leaping from one tree to another, thus doing away with the need to even touch the forest floor! This is especially true for big males; smaller animals tend to be not as shy and this timidity seems to develop more with age. If you catch an adult butaan and then let them go, they never return to the place where you caught them.

This brings us to a discussion on the butaan’s intelligence. This monitor lizard demonstrates good spatial memory. All animals have some sort of spatial memory, but frugivorous animals have a more distinctive and complex memory system. The butaan remembers 1) where the fruit-bearing trees and plants are and 2) when they produce fruit. It remembers when it has eaten fruit from a particular plant even from years ago. While most frugivores have wings and can thus follow each other visually to fruit sources, the butaan does not have this luxury. It has to have a cognitive system of spatially mapping out fruit sources over an extensive area.

While the butaan eats snails and  crabs, fruits comprise a major part of its diet. The butaan eats a combination of sugary (ex: Grewia or kiling) and oily/waxy fruits (ex: pandanus), although it consumer the latter in greater quantities. Curiously, most vertebrates tend to reject oily fruits as they contain chemicals that make pulp indigestible. This leaves the butaan with practically zero competition when it comes to oily fruits! The fruits that the butaan prefers tend to be quite common even in degraded habitats.

Pandanus, one of the butaan’s favorites, deserves a bit of elaboration. The pandanus plant is found all over the Philippines. There are over 60 species in the Philippines and about 700 worldwide. Very few animals in the world eat pandanus fruits. Yet it is interesting to note how it clearly evolved to be eaten by animals – it is highly fragrant and brightly colored, but takes considerable strength to remove individual ripe fruits. Bennett suspects (although it cannot be proven) that when elephants roamed the Philippines about 10,000 years ago, pandanus was a major food source. When the elephants died out, pandanus lost its main dispersal agent except in places where these giant fruit-eating lizards occur because they are strong enough to rip through the tough exterior. They subsequently deposit the fruits/seeds as feces on the forest floor where they germinate all over the place, sometimes quite some distance from the parent plant. Thus, one of the evidence of butaan presence is the location of sprouting pandanus plants – if they are uphill from a parent plant, then the evidence suggests that a butaan must have been intervened.

Research suggests that the butaan leave some sort of olfactory signals to other butaan. The butaan apparently rub their heads against the bottom of the trunk as evidenced by scratches on the tree trunks. Why they leave these scent signals remains a mystery. The signals could alert other butaan to the presence of abundant fruit. Could it be that the survival of so specialized a species relies on their helping each other find fruit? After all, the fruit may be so abundant that the presence of more animals won’t reduce the available by a significant amount. Or could it be that the signal is a good way of finding mates?

It is difficult to breed the butaan in captivity. First, it needs a large enclosed space with plenty of hiding places. These monitor lizards are intolerant of each other and may need to be put up in separate enclosures. They enjoy being sprayed with water and should be provided with frequent showers. The frugivorous portion of the butaan’s diet is extremely difficult to replicate in captivity and thus, most captive individuals are fed a carnivorous diet, which results in intestinal and digestive problems in the long run. Copulation has been observed in captivity and appears to be gentler compared to other species of lizards. Reproductive activity occurs between June to September when there is high rainfall. Female lizards are capable of producing more than one clutch of eggs per year but thus far, there has been only one juvenile butaan that has been successfully bred in captivity (in Avilon Zoo, Montalban).  There is also some evidence of long-term pair bonding.

Peculiar study methods

As mischievous as it looks, the butaan seems to be playing peek-a-boo with biologists, appearing and disappearing through the years. With only one specimen in the British Museum, the butaan was considered extinct between 1845 and 1976, until it was rediscovered by Walter Auffenberg of the Florida State Museum in Luzon and Catanduanes. Auffenberg attests that it is possible to spend years in the forest without being aware of the butaan’s presence. Furthermore, despite the sheer size of the butaan, it seems inconceivable how competent biologists working for decades in places such as the Sierra Madres have failed to see it. Auffenberg’s (1988) study in the 1970s involved the death of 110 of his 126 study animals. Auffenberg used a surefire way to capture the butaan – dogs. However, a dog’s bite is lethal for a butaan since the latter is incapable of fighting infections sustained from such injury. The scientific paradigm during that time must be taken into account in understanding Auffenberg’s study – killing and opening up animals for study was a conventional and accepted method of research.

Given the rarity and the vulnerable status of the butaan, as well as the increasing consideration given to the animals under investigation, Bennett considered using alternative non-destructive and non-intrusive methods in studying the ecology of the lizard. Before Bennett embarked on his research, the butaan, in its elusiveness, seems to be almost mythical to him. How is it possible to know anything about it without harming it in any way? Faced with this challenge, Bennett developed creative methods to learn more about the butaan. This includes searching for and studying butaan feces on the forest floor, spotting individual animals on exposed trees (observation done in specially designed hides), noting the scratch marks on the trunks of trees that the butaan frequents, taking pictures of the butaan using cameras with motion triggers set at potential refuge and food trees, gluing colored beads into the fruits the butaan eats (to track seed dispersal patterns), and the use of reels of thread attached to the tail of  rescued butaan (to reveal movement patterns).

These methods are far from simple or easy. For instance, if you want to catch a glimpse of a butaan on a particular tree, you have to wait quietly inside a hide for 11 hours! As if this were not difficult enough, you also cannot eat or use mosquito repellant, and you have to pee into a bottle because the butaan has an ultra sensitive sense of smell! Gluing beads into individual pandanus fruits may seem like fun at first but it is essentially a tedious, mind-numbing task, especially if you have seen how many fruits there are! And the camera traps? Well, there are many false alarms and the camera traps get triggered by the movement of playful monkeys! For Bennett, it is always a privilege to see a live butaan in the wild, and a joy as well to gather signs of its presence.

Ambiguous future

The conservation status of the butaan, as listed in the IUCN (International Union for the Conservation of Nature and Natural Resources) Red Book, is vulnerable. The only other monitor lizard that has the same vulnerable status is Indonesia’s Komodo dragon, an enormously famous animal that receives a lot of funding for its study and conservation. Many documentaries have been made about the Komodo dragon. Until last year, no documentaries have been made about the butaan. Very few Filipinos know what the butaan is and they are amazed to learn of a fruit-loving monitor lizard that is so big yet so shy and that can only be found in the Philippines.  With the insidious destruction of forests in most parts of the country (and the relative inaccessibility of Polillo), the butaan might not be found anywhere in the world outside of the 200 km radius from Polillo!

The main threat to the butaan’s survival is the destruction of large shelter trees situated on the tops of hills. As discussed earlier, the butaan spends very little time on the ground, preferring to stay up in tall, emergent trees sheltered with vine thickets. It is almost impossible for the animal to survive outside the forest. Unfortunately, the trees that the butaan favors are the very same trees prized by loggers. The loss of trees means a loss of safe places for the butaan to hide.  Local people usually hunt the butaan with dogs. When a dog spots a butaan and chases it, the latter immediately runs up a tree to keep safely out of reach. If the tree is big and tall, the butaan is quiet safe. However, in degraded habitats where there are very few good shelter trees, the butaan often runs up a tree that is small enough to be felled easily with a bolo within minutes.

The butaan is also especially vulnerable to forest fragmentation. As discussed earlier, the butaan eats many different kinds of fruits since each fruit contains different nutrients. Some fruits are more abundant in some forest areas than in others. Thus, a butaan has to move around the different forest areas to complete its diet. When the forest is fragmented, the butaan has to cross open areas where it can easily be hunted and killed.

At present, conservation efforts are directed at safeguarding the forests that are home to this exceptional monitor lizard and conducting regular counts to assess its status. There have been informal efforts at promoting awareness of the butaan’s uniqueness, as spearheaded by Mang Enteng, the Wildlife Warden of Polillo. According to Mang Enteng, it is important to gain the trust and the respect of the local people first, before they will begin to listen – this confirms the principles of indigenous psychology as elaborated by Virgilio Enriquez. Mang Enteng shares how he used to be renowned for his exceptional skill and knowledge in hunting different kinds of wildlife. He even kept a notebook with a schedule of when the various trees in the forest bear fruit. With his timetable, Mang Enteng could guarantee when animals would visit these trees. However, when he was converted to be a conservationist, Mang Enteng burned this notebook for fear that this information could be dangerous in the wrong hands. Now he regrets doing so as it would have been a great help in his assessment of wildlife. With his barkada (group of friends) of former hunters, Mang Enteng leads a team of stewards for the environment. The local people of Polillo also run to him to report about hunters and loggers.

In a rural community like Polillo, informal means of spreading awareness seems to be most promising.  In relaxed atmospheres, friends share stories of the rare and magnificent butaan over lambanog. Grandparents describe the butaan to their grandchildren.  But still, conservation education continues to be a challenge in a predominantly poor country. People go to the forests for all their needs that require wood. They also clear patches of forests to plant rice and other food crops. The concrete economic value of forest timber leads to its inevitable exploitation by the underprivileged. It is difficult to even begin talking about conservation when the poor experience nagging hunger pangs. Perhaps the community might want to consider adopting a different approach such as setting aside areas of forests with active replanting programs where people can get their wood.

The continued existence of the butaan is contingent on the ability of immediate communities to coexist in shared habitats, and to confer the importance deserved by the remaining treasures of our rainforest.

Footnotes:

1. The butaan can be found in southeastern Luzon, Catanduanes and Polillo.  Its occurrence could have been more extensive in the past, but the destruction of lowland forests have led to its diminished status. At present, extensive studies are being conducted only in Polillo.
2. For reference, the total land area of Polillo is 761 km².
3. As a demonstration, refer to Bennett’s video footage of a young butaan virtually supporting itself with the lower half of its body while stretching away from the tree in an effort to pull out individual fruits from a hanging clump of pandanus fruits.

References:

Auffenberg, W. (1988). Gray’s monitor lizard. Gainesville: University of Florida Press

Bennett, D. (1995).  A little book of monitor lizards. Aberdeen: Viper Press.

Bennett, D. Gray’s monitor lizard on Polillo Island, Philippines.  Published article.

Bennett, D. Non-destructive methods of investigating the distribution, diet, and movement. Unpublished paper.

Bennett, D. Habitat use and status of Gray’s monitor lizard, Varanus olivaceus, on Polillo Island, Philippines. Unpublished paper.