Spotted Poison Frogs:
Dendrobates captivus expedition, Rio Santiago, 2006

Part one:
In pursuit of the Pongo

Background
In 1924, geologist Harvey Bassler collected a small frog from the confluence of the Río Santiago and Río Marañón in northwestern Peru. Five years later, after collecting a bizarre frog from the Cordillera del Condor, Bassler collected two more frogs from the Santiago-Marañón junction on his way down the Marañón in a dugout canoe. These specimens were forgotten until being found in a museum collection in 1975, but it wasn’t until Charles Myers’ 1982 paper that these specimens were regarded as distinct species, naming the Cordillera del Condor species Dendrobates mysteriosus and the species from the Santiago D. captivus. Unfortunately, Bassler left no descriptions of live animals, leaving Myers only damaged specimens that had been in alcohol since the start of the Great Depression.

Rainer Schulte traced Bassler’s footsteps to the Cordillera del Condor, and in 1989 documented the first live Dendrobates mysteriosus. However, no such expeditions were ever attempted to rediscover Dendrobates captivus, and understandably so. The type locality as described by Bassler is located in an extremely remote area of Peru, accessible by following the Rio Marañón several days in a boat, only to be greeted by the infamous Pongo de Manseriche. This pongo, or rapid, is formed by a precipitous gorge that cuts through the Cerros de Campanquis, restricting the 750 meter-wide Marañón to a violent 120 meter-wide maelstrom. The peril of reaching the site is exacerbated its inhabitants, the Aguarunas, a sub-tribe of the Shuar Indians, who are most well-known for their curious practice of shrinking the heads of their enemies. These natives have a notorious reputation in Peru of being both fearful and aggressive towards foreigners, especially white ones, who they view as pishtacos (assassins whose primary objective is to extract fats from the bodies of their victims).

The secluded and dangerous nature of the Santiago valley has consequently made it one of the most poorly investigated areas of Peru. Very few biological investigations have been made in the area, and no herpetological surveys, aside from Bassler’s collection of D. captivus, had ever been attempted. For this reason, we decided to go, attempting to find a poison frog that hadn’t been seen by any scientist in 77 years. The expedition was conceived and planned by myself (Evan Twomey), Justin Yeager, Jason Brown, and Manuel Miranda (our contact with the Aguarunas). We were accompanied by Wouter Olthof (a Dutch student), and a small group of filmmakers (Collin Kettell and Richard Sines), an agronomist, and two Peruvian field-hands.

Day 1
Tarapoto – It is night, our truck is packed to the gills with people and supplies. In total there are ten of us leaving from Tarapoto, with the final destination of Rio Santiago, type locality for the elusive Dendrobates captivus. Tonight our only destination is Yurimaguas, a thriving port-town 4 hours north by road, but recent road-assaults have us all on edge. Despite the kidney-busting condition of the road, our excitement levels are through the roof, even though we are a long ways from our final destination. In Yurimaguas we hope to get a boat that will take us the rest of the way, two full days, by river.


Day 2
Yurimaguas – Getting up at 5 am was never so easy. Even though we didn’t get in until midnight, and had to spend the rest of the day on the boat, everyone jumped out of bed, anxious to make progress towards our final destination. Today is San Juan, the biggest holiday of the year for people living in Amazonian Peru. The preferred food on this day is a juane, a delicious but somewhat frightening tamale consisting of rice, hen, and egg, all wrapped in a leaf, so we bought a sack of them for the long ride ahead. Our plan of action was to descend the Rio Huallaga until the junction of the Marañón, whereupon we would make a westward turn to approach the Pongo de Manseriche from the east. After a long morning in the boat, we finally made it to the confluence of the Huallaga and the Marañón. The Rio Marañón is the primary headwater of the Amazon river, flowing briskly away from the Andes, and finally slugging its way across the lowlands to pick up the Rio Huallaga, and finally the Rio Ucayali, where the Amazon officially begins. From this point on, we would be fighting the current, so our progress would be substantially slowed. By nightfall, we only made it as far as San Lorenzo, a bustling town near the mouth of the Rio Pastaza. Here we replenished our enthusiasm with some more juanes and beer.

Day 3
San Lorenzo – Another day in the boat was ahead of us, but the possibility that we might make it in the field today had everybody anxious to get going. After fueling up, we continued our ascent of the Marañón. Before long, a chain of mountains rose out of the horizon: we were looking at the Cerros de Campanquis, the Andean front-range that effectively isolates the Santiago valley from the rest of Amazonia. By lunchtime we had made it to Sarameriza, an isolated but lively town a few hours downriver of the Pongo de Manseriche. After Sarameriza there were no more towns with gas stations, so we had to carry enough gasoline to last our boat for the next four days. Our boat driver had a change of heart – he did not now feel comfortable navigating the Pongo de Manseriche, having only done it once, several years back. Being in a town so close to the Pongo, we were able to find a young man with extensive experience navigating the area, being comfortable with both the Pongo de Manseriche and the natives living above it. After leaving Sarameriza and continuing up the Marañón, the excitement in the boat reached an all-time high. The Cerros de Campanquis rose higher and higher above the horizon, until they appeared as a massive green wall of virgin rainforest. By mid-afternoon, we had reached the tiny village of Borja, an old missionary station situated immediately under the shadow of the Pongo de Manseriche. This would be our last stop before the Pongo and our last stop before entering Aguaruna territory.

As we left Borja and made our way to the mouth of the Pongo, we realized that the peaceful lower Marañón had finally given way to a monster: a narrow canyon with powerful currents, whirlpools, and huge rocks. We were finally in a position to see the bottom of the Pongo de Manseriche, and it looked like someone had taken a huge axe and smashed the Cerros de Campanquis, leaving only a small sliver for a pass. To navigate the Pongo, one must pass through two treacherous straits, the first being where the Marañón smashes into a massive crag,  forming an enormous maelstrom, locally known as the huaccanqui (literally, “you’ll cry” in Aguaruna). Passing this strait, one is then faced with a second, more perilous section know as the asnahuaccanqui (“you’ll cry until you rot”), a 100-meter stretch of whitewater riddled with boulders and whirlpools. As we made our way slowly and carefully up the Pongo, it felt like we were entering another world. The rocks were filled with strange birds (reminiscent of blue-footed boobies) and orchids, and long strands of moss hung from the trees and cliffs due to the constantly misty conditions inside the gorge.

When we asked our guide where we were going to camp, we thought he was joking when he told us we would make base camp inside the Pongo itself. However, after making it through the roughest spots, we were pleased to find a beautiful sand beach, surrounded by cliffs and mountains, the Marañón roaring past. Stopping here, we quickly unloaded the boat -  there was still the chance at getting in the field for maybe an hour.

After only a few minutes in the forest, we spotted a small red frog on the forest floor, which Justin Yeager, having experience with Ecuadorian frogs, identified as Epipedobates parvulus. Further searching turned up more of this species, but the limited daylight cut short our search. The search for Dendrobates captivus would have to wait until tomorrow.

Meanwhile, our guide Manuel Miranda, along with an Aguaruna translator, were above the Pongo negotiating with the Aguarunas for us to enter their land the following morning. They returned later that night, several hours later than anyone anticipated. When we asked how negotiations went with the Aguarunas; a somber Manuel replied “Not good.”

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