Our quest to see the amazing biodiversity found on Earth has brought us to Sulawesi, one of the islands that comprise the Asian country of Indonesia. Sulawesi is special because it is located in a transitional zone between Asia and Australia and has animals of both origins. Our goal was to find some of these endemic mammals found here and nowhere else on the planet. We were greeted at the Gorontalo Airport by our guide Carlos Bocos and local staff. We piled into a Toyota 4x4 for the 5-hour drive to Nantu Village. We settled into our guesthouse and waited out a torrential thunderstorm before venturing into nearby Nantu Forest for a night walk.
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| Marc in the Nantu Guest House |
We were joined by two rangers who led us past cornfields and coconut plantations to the shore of the raging Paguyamon River. The water was deep and swift, and Marc and I each latched onto a ranger for the crossing. We made it safely across and followed a path to the rangers’ station. We were fortunate to have been allowed into the forest after dark, as night walks aren’t usually allowed.
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| Meeting the Forest Rangers |
The first mammal we encountered on our walk was a Sulawesi Rousette or Sulawesi Fruit Bat, one of the more common species found here. The Sulawesi Rousette is endemic to the island of Sulawesi and is the only member of the genus Pilonycteris.
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| Sulawesi Rousette |
One of the rangers spotted a Jatna’s Tarsier, one of the species I most wanted to see! Jatna’s Tarsier is a tiny nocturnal primate endemic to northern Sulawesi. In 2017, Jatna’s Tarsier was split from Gursky’s Spectral Tarsier due to their distinct and separate acoustic duet calls between males and females.
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| Jatna’s Tarsier |
We weren’t picking up any eyeshine with our headlamps and had to rely on Carlos’s thermal imager to spot mammals. He detected a second species of fruit bat, a Wallace’s Stripe-faced Fruit Bat, another Sulawesi endemic and listed as near threatened by the IUCN.
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| Wallace’s Stripe-faced Fruit Bat |
The night was capped off by a second Jatna’s Tarsier, two species of frog, and a land snail. It was getting late, so we headed back to the rangers’ station. Near the river, I spotted eyeshine! It turned out to be four Javan Deer, an introduced species here.
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| Javan Deer |
We were up early the following morning in anticipation of seeing a Babirusa, a bizarre species of wild pig that was on my most-wanted-to-see list. It meant crossing the swiftly flowing river again and hiking a mile into the forest to a hide that had been set up at a salt lick or bai.
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| Babirusa Hide |
We sat quietly in high hopes that the Babirusa and Sulawesi Warty Pigs would enter the bai. Around 9:00, Marc spotted a macaque! Two Heck’s Macaques entered the bai and sat on a log on the edge of the clearing, but we didn’t have a great view of them. After 15 minutes, they got up and recrossed the baie so Marc was able to get some good photos.
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| Heck’s Macaque |
We waited and waited for the pigs to arrive, but they were a no-show. A few birds, mostly doves, dragonflies, and a lizard entertained us. While Marc was trying to photograph the lizard, I spotted a Common Water Monitor crossing the bai. About 5 minutes later, we heard something big rustling through the grass. It was the monitor lizard. It almost entered the hide but saw us and tore off! It was nearing 3:00 pm, and we had given up hope that the Babirusa and Sulawesi Warty Pigs would show up. I was bummed but we still had tomorrow to try again. No sooner had we set off when the skies opened up and we were drenched in the sudden downpour. We rushed to the river to cross before it got too high, not even bothering to change into our river shoes.
We were up for an early breakfast and departure for our second attempt at the hide. There were more clouds around this morning, and I hoped they’d disperse as the sun rose higher. We hiked to the river, and the sight before us left us all in dismay. The river had risen significantly and now reached the log where we had changed our shoes yesterday!
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| Swollen River Crossing |
Carlos stripped down to his shorts to test the waters. He made it across, but the water was up to his crotch. It would be above my waist. He returned, and it was clear he had to use all his body strength to fight the current. There was no way we could make it safely across. Curses, we’d miss the Babirusa and Sulawesi Warty Pigs! We had no choice but to return to the guesthouse and decided to move on to our next destination.
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| Leaving Nantu |
It ended up taking us 10 hours to reach the Totabuen Citawaya Hotel in the city of Kotamobagu! The hotel was very nice and modern, with a hairdryer to help dry out our still soggy boots. After dinner, we prepared to do a night walk in Bogani Nani Wartabone National Park, also known locally as Toraut, an hour’s drive away. To enter the park, we had to cross a creek on a bamboo raft. On the other side, we entered the forest and found our first mammal, a Gursky’s Spectral Tarsier. Named for Dr. Sharon Gursky, this tarsier is the one from which Jatna’s Tarsier was split in 2017.
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| Gursky’s Spectral Tarsier |
With his thermal imager, Carlos spotted what he thought was a Sulawesi Dwarf Cuscus, but it turned out to be a Sulawesi Giant Rat. We did see two more rats, both were Northeastern Xanthurus Rats.
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| Northeastern Xanthurus Rat |
A very unusual bat, a Pallas’s Tube-nosed Fruit Bat, was spotted. It had yellow spots on its wings, which I thought were leaves. I’d never heard of a bat using camouflage for roosting, but why else would it evolve this way? I later read that “ with their brown, yellow and pale green splotches, Tube-nosed Fruit Bats have amongst the most colorful wings of all bats. The patterning acts as camouflage, resembling dead leaves when at rest amongst rainforest trees.”
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| Pallas’s Tube-nosed Fruit Bat |
Although mammals were the focus of our night walk, we weren’t ignoring the birds. Carlos got very excited when he spotted a tiny bird roosting on a branch above the trail. It turned out to be a Rufous-throated Flycatcher, a near-threatened species that is usually difficult to see.
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| Rufous-throated Flycatcher |
We also saw a few tiny Mouse-eared and Woolly Bats hanging from twigs. Identifying them to the species level proved difficult. The final bat species we could identify were Dark Sheath-tailed Bats roosting under a palm frond.
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| Dark Sheath-tailed Bats |
The most exciting find of the night was a Small Sulawesi Cuscus! It was high in a tree, making photography difficult but not impossible for Marc.
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| Small Sulawesi Cuscus |
We made our way back to the creek, crossed on the bamboo raft, and drove an hour back to our hotel. We turned in around 2:00 am after a very long day. The following morning, we returned to the park to search for Gorontalo Macaques along the road. They were proving to be elusive, but we managed to pick up a new mammal, a Whitish Dwarf Squirrel. Finally, our guide spotted a small troop of macaques in the forest. It was difficult to get a clear view, but we managed a glimpse here and there.
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| Gorontalo Macaque |
The Gorontalo Macaque is one of seven macaque species endemic to Sulawesi. They are range-restricted to the central section of the northwestern peninsula, where they spend 96% of their time in the trees. We returned to our hotel and, after a late lunch, drove to our next destination, Tangkoko Batuangus Nature Reserve. We arrived late, and after the long drive, we decided to forego a night walk.
Morning came quickly, and we were up early to start our search for Sulawesi’s more famous (or infamous) residents, the Celebes Crested Macaques. We were joined by local guide Enyse and followed a trail through lowland forest. Enyse spotted a Bear Cuscus, one of our key targets! We got a decent view before it climbed higher into the foliage. We were walking away when Carlos noticed it was coming back down. The cuscus perched in the open on a thin branch and watched us, amazing!
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| Bear Cuscus |
The Bear Cuscus is an arboreal marsupial endemic to Sulawesi and the surrounding islands. Very little is known about these intriguing animals. There were two more Bear Cuscus, but they were high up in the trees. We headed off into the forest to look for squirrels and roosting bats. Carlos searched every hollow tree for bats and managed to find a Lesser Short-nosed Fruit Bat, a male and female Sulawesi Horseshoe Bat, and some Lesser False Vampire Bats.
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| Lesser False Vampire Bats |
Enyse got a call that the macaques had been located, and we headed back towards the beach to find them. We reached the main trail and turned left. Enyse got a call that the macaques had moved, so we turned around and headed in the opposite direction. We soon encountered a large troop! Enyse said there were up to 70 individuals in this group.
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| Celebes Crested Macaque |
They were well habituated, and you could approach closely, although we kept a safe distance. The males have large canines and can be aggressive.
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| Celebes Crested Macaque |
The Celebes Crested Macaques live in Tangkoko and on some smaller neighboring islands. They are critically endangered, with only 4000 to 6000 in Tangkoko.
So what makes the Celebes Crested Macaque the island’s most famous resident? The answer may surprise you. They were involved in several disputes regarding the copyright status of selfies taken by the macaques on a game camera set up by a British wildlife photographer, David J. Slater! The court ultimately ruled in favor of Slater, finding that animals have no legal authority to hold copyright claims. Slater’s legal battles left him broke and depressed, but he was delighted that the publicity had led to tourists visiting to see the monkeys, providing a longer-term benefit to the community and the impetus to protect the Celebes Crested Macaques.
We watched as the group foraged for fruit in the forest or through trash on the beach. One male was banging a coconut on a rock to get at the meat inside.
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| Celebes Crested Macaque |
Infants were nursing or playing with one another. Young males were aggressive towards each other, and several fierce scrabbles broke out. We left the group in peace and headed back to the car park.
After some downtime, we returned to the reserve in the late afternoon to visit a tarsier roosting tree and wait for the primates to emerge at dusk. Other tourists, the first we had encountered on our trip, had already gathered at the “Tarsier Tree”. A Gursky’s Spectral Tarsier poked its head out around 5:45, and naturally, everyone wanted to take its photo. At about the same time, Marc spotted another mammal heading down a branch toward the trunk. It was a Celebes Dwarf Squirrel, a mammal we had yet to see. Unfortunately, in all the tarsier commotion, it fled back up the branch. A pair of tarsiers eventually emerged, giving everyone good views and photos.
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| Gursky’s Spectral Tarsier |
We headed off into the forest to look for rats and bats. Carlos was picking up many rats with his thermal imager, but they were impossible to get a look at, let alone photograph. We chased them for nearly two hours before one froze in a tree, and Marc was able to photograph it.
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| Northeastern Xanthurus Rat |
The following morning, we returned to the reserve with Enyse to search for a Celebes Dwarf Squirrel to photograph. Carlos kept looking under palm fronds for roosting bats and found a new species, Peters’s Fruit Bat.
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| Peters’s Fruit Bat |
He lifted one frond and became very excited when he found some very unusual bats. These bats were clearly different, cream-colored with pink faces. The hope was that they were a new species for Carlos. Further investigation proved them to be Hardwickie’s Woolly Bats, a species that Carlos has already seen, but never in this area.
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| Hardwickie’s Woolly Bats |
As we were nearing the end of our walk, Carlos and I heard what we thought might be a squirrel. Could it be, yes, a Celebes Dwarf Squirrel! There were actually two, and Marc was able to get a good photo.
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| Celebes Dwarf Squirrel |
We returned to the lodge where we said goodbye to Enyse and thanked him for finding so many amazing mammals for us.
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| Leaving Enyse |
After lunch, we drove to Manado, where we would spend our final night on Sulawesi. A big thank you goes to Olva and Brian for organizing the logistics and making sure everything ran smoothly during our stay. Our sincere gratitude goes to our driver, Maikel, who got us safely from one destination to the next and whose good company made the long drives pass more quickly. Finally, to our fearless leader, Carlos Bocos, who made this trip possible, and for his boundless energy in finding mammals and birds!
On to West Papua with Carlos, where hopefully more wondrous creatures and epic adventures await us!
We hope all is well with everyone.
Peggy and Marc
Our route map:
Sulawesi Mammal List: May 15 - 20, 2024
| No. | Species | Scientific Name | Comments |
| 1 | Sulawesi Rousette | Pilonycteris celebensi | Nantu |
| 2 | Wallace’s Stripe-faced Fruit Bat | Styloctenium wallacei | Nantu |
| 3 | Jatna’s Tarsier | Tarsius supriatnai | Nantu |
| 4 | Javan Deer | Rusa timorensis | Nantu |
| 5 | Heck’s Macaque | Macaca hecki | Nantu |
| 6 | Pallas’s Tube-nosed Fruit Bat | Nyctimene cephalote | Toraut |
| 7 | Gursky’s Spectral Tarsier | Tarsius spectrumgurskyae | Toraut & Tangkoko |
| 8 | Mouse-eared Bat | Myotis sp. | Toraut |
| 9 | Woolly Bat | Kerivoula sp. | Toraut |
| 10 | Dark Sheath-tailed Bat | Mosia nigrescens | Toraut |
| 11 | Northeastern Xanthurus Rat | Rattus xanthurus | Toraut |
| 12 | Small Sulawesi Cuscus | Strigocuscus celbenis | Toraut |
| 13 | Whitish Dwarf Squirrel | Prosciurillus leucomus | Toraut |
| 14 | Gorontalo Macaque | Macaca nigrescens | Toraut |
| 15 | Bear Cuscus | Ailurops ursinus | Tangkoko |
| 16 | Lesser Short-nosed Fruit Bat | Cynopterus brachyotis | Tangkoko |
| 17 | Sulawesi Horseshoe Bat | Rhinolophus celebensi | Tangkoko |
| 18 | Lesser False Vampire Bat | Megaderma spasma | Tangkoko |
| 19 | Hardwicke’s Woolly Bats | Kerivoula hardwickii | Tangkoko |
| 20 | Celebes Crested Macaque | Macaca nigra | Tangkoko |
| 21 | Polynesian Rat | Rattus exulans | Tangkoko |
| 22 | Peters’s Fruit Bat | Cynopterus luzoniensis | Tangkoko |
| 23 | Celebes Dwarf Squirrel | Prosciurillus murinus | Tangkoko |
For a complete list of non-avian observations made during our trip, visit my iNaturalist journal post at:
