The AGOUTI'S Nutty Friend - inter-dependence of the Brazil nut trees and the reclusive animals called agoutis

International Wildlife, March-April, 2000 by David Taylor

A small rodent and the towering Brazil nut tree have one of the most important relationships in the Amazonian forest

Walking up a narrow trail through the tangled undergrowth of the Peruvian rain forest, we came across a small piece of puma scat on our path. It was early and the forest was quiet, and I was looking for an agouti, a cat-sized rodent and subject of Enrique Ortiz's recent research. But when the puma scat prompted Ortiz to tick off a list of predators in the area--jaguars, pumas, harpy eagles, anacondas--I wondered, "Why are we concerned with agoutis?"

"Because none of the others can break open a Brazil nut pod," said Ortiz, a biologist now working at the Smithsonian Institution's National Museum of Natural

History in Washington, D.C. Ortiz was exploring one of the strangest and most influential relationships in the Amazonian forest, and I was tagging along. The towering Brazil nut tree (as tall as 150 feet) and the diminutive agouti (about 1 foot tall) make perhaps the world's most extreme Mutt-and-Jeff team, each dependent on the other for its survival. Yet despite the Brazil nut's importance to the economy and the ecology of large parts of South America, very little was known about this partnership when Ortiz started his research on Brazil nut ecology 10 years ago.

Brazil nut trees are among the oldest and tallest in the Amazon, with some dating back more than 1,100 years. They grow from eastern Peru and northern Bolivia across the Brazilian Amazon. Brazil nuts are a crucial source of nutrition and livelihood for more than 400,000 Amazonians involved in their collection and sale, a business that generated more than $65 million worldwide in 1998. It's one of the most traveled nuts in the world, and one of the last products in international trade that comes exclusively from natural forests. (Attempts to establish commercially viable Brazil nut plantations have failed.)

Where there are Brazil nuts, there are agoutis to eat them. Agoutis are smaller than their relatives the piglike pacas and larger than squirrels, which they resemble. Their large heads and bulging jaw muscles are the only hints of their power to shape the rain forest.

Agoutis are reclusive animals, and if it weren't for the strange interconnections of biology, their crucial role in the ecology of the Amazon might still be unheralded. But Enrique Ortiz was determined to help save the Brazil nut forests in his native Peru, and that desire eventually led him to become one of the world's leading agouti experts. At his research site at the edge of the Bahuaja-Sonene National Park, in southeastern Peru, Ortiz and his assistants use a variety of surreptitious methods for tracking the rodents and unlocking their secrets.

To get to this research site in February 1999, we traveled down the Madre de Dios River from Puerto Maldonado, the provincial capital, in a 30-foot-long canoe. It was the height of the annual Brazil nut harvest (which lasts from December to February) and therefore a good time to check on the trees' regeneration and the agoutis' activity. As we floated down the eddying river, Ortiz explained that, for reasons that are still not clear, this area has the highest concentration of Brazil nut trees (known locally as casta-as) in all Peru. "If we're lucky," said the 41-year-old biologist, who has a young, intense face that even a trim beard and flecks of gray don't seem to subdue, "we'll see an agouti."

We passed a profusion of palms, fruit trees, lofty hardwoods and cane grasses. Ortiz and his field office director at the time, Fernando "Pino" Rubio del Valle, pointed out several birds with North American relatives--orioles and anhinga--and an osprey, which migrates between North and South America. In the distance, a high bank of red clay appeared, and on it three lofty tree crowns. Rubio del Valle pointed them out to me and said, "There's your first casta-a!"

We turned up a narrow tributary, the Palma Real Grande, and reached the campsite as darkness was falling. We were met at the riverside by a small group of Brazil nut pickers, or casta-eros, led by a man in pink- and-blue shorts. He was Fernando Cornejo, one of Peru's leading botanists. The camp was a simple spread of thatch over a cooking area and a wooden table. The Brazil nut collectors live near Puerto Maldonado and come here during the rainy season when the trees drop their coconut-sized pods. Inside each pod, the Brazil nuts (seeds, actually) are arranged like slices in an orange.

Ortiz and Cornejo talked late into the night, discussing their work. Besides quantifying the bewildering range of life in the area, they're also trying to get a handle on the economics of Brazil nut collection as part of Ortiz's Casta-ales Project. This project, for which Cornejo is research director, works with as many as 60 Brazil-nut-picking families in an attempt to uncover ways to make the harvests more efficient, improve the workers' livelihoods and ensure a healthier forest.

Just after dawn we got back into the boat and made for Oculto, the project's research site. At Oculto, over a breakfast of rice and eggs, the talk turned to agoutis. "They're hard to see," Ortiz said. "When they see you, they freeze. For a long time." To test that, Rubio del Valle and I walked up the path, macaws screeching high above us. We came to a spot where a huge tree had fallen, opening a clearing in the canopy. Four or five strands of pink flagging marked experimental plantings of seedlings, intended to bolster the forest's natural regeneration. Around one slender plant stood a chest-high column of wire mesh.