Around 4:30, Ellen suggested we stop work and go to the river beach for a swim. I was leery of swimming in a river with piranhas and caimans. The water at this beach was shallow and I was assured that the piranhas did not live in such shallow water.”

So Lee Davis of Orono wrote in her journal a little over a year ago. She was on an Earthwatch expedition to the Pantanal in Brazil, one of the world’s largest wetlands. As she had caught piranhas in water that didn’t seem much deeper than that swimming spot, she had her doubts, but the afternoon was hot, so she risked a swim. And didn’t get attacked.

Piranhas are shaped like sunfish and grow to about a foot long and have extremely sharp teeth. Caimans are a type of crocodile that grow to be 6 to 10 feet long. They also have impressive teeth.

Lee Davis and her husband, Ron Davis, both biologists, were engaged in studying fish, trees, mammals, birds and insects in the southern part of the vast Pantanal ecosystem. Not your typical vacationers, the retired University of Maine professors collected fresh fruits, examined scat, analyzed water samples and took lots of photographs.

They will show slides and tell about their experiences at 7:30 p.m. Wednesday, Nov. 3, at Fields Pond Audubon Center in Holden.

South of the Amazon, the Pantanal extends through central-west Brazil, eastern Bolivia and northeastern Paraguay. Its waterways, grasslands and forests are home to hundreds of species of birds, capuchin and howler monkeys, capybaras, anacondas, tapirs, the endangered jaguar, giant river otters and increasingly rare hyacinth macaws. The Davises visited it in September 2003, spring in the Southern Hemisphere, just before the start of the rainy season, when the Pantanal floods. Temperatures were in the 90s.

The Davises stayed at Fazenda Rio Negro (Black River Ranch) for 10 days with a small group of Brazilian scientists, graduate students and other volunteers. The ranch was purchased from a cattle-raising family in 1999 by Conservation International, which works with Earthwatch to manage the area as a haven both for wildlife and researchers.

During the day they took turns doing various tasks. They fished with barbless hooks so they could measure and photograph the fish before returning them to the water.

“We boated and fished in the Black River. I caught the first piranha, but we got 2 more, 1 paku, 1 dorado, and 1 catfish. The boat ride was pleasant because the sun was behind clouds. We saw 2 jabiru storks and 2 roseate spoonbills. A caiman hung around and tried to get any fish that we landed.” – Sept. 12, 2003.

Their guide, Lico, handled the piranhas they caught, because he knew how to avoid getting bitten, Ron Davis said in a recent interview.

Some of the fish species eat fruit that falls into the water, he said, and macaws also eat fruit.

“Met Ellen at 7 in the morning to walk trails to search for fresh fruits. We also collected scat. We got back late for the midday meal because we found a lot of feral pigs and peccaries at noon. There were many interruptions to observe wildlife: 3 giant anteaters, including a baby; crab-eating foxes; 2 types of deer; king vultures; a coati; and jabiru storks on their nest.” – Sept. 13, 2003.

In addition to seeing peccaries (a type of wild pig) and feral pigs (domesticated pigs gone wild), the Davises saw capybaras, at 4 feet long and 80 to 140 pounds the largest living rodents, and giant river otters, extending to 7 feet including their tails, long, narrow, playful and curious.

“They were as interested in us as we were in them,” Lee Davis said.

They also saw rare hyacinth macaws, a type of large, long-tailed parrot, a beautiful indigo blue, often stolen for the pet trade. These birds pair for life and live for decades, Ron Davis said.

Lee Davis’ major disappointment was that they did not see a jaguar, although they saw its tracks. Jaguars are endangered and nocturnal, so they are hard to spot.

But on a trip probably not for the fainthearted, the Davises did see snakes – the deadly Fer de Lance, Amazon tree boas, and anacondas, at 15 to 20 feet perhaps the largest snakes in the world.

After their Earthwatch stint, the Davises went on a couple of ecotours organized by Focus Tours. They stayed at an old monastery in the mountains of eastern Brazil, where Lee Davis was thrilled to see a maned wolf one night. Maned wolves are longer-legged but lighter-bodied than North American wolves. As their name suggests, they have manes.

Since they don’t breed in captivity, you hardly ever see them in zoos, she said. The monks put out trays with pieces of raw chicken, and around 11 p.m. a wolf appeared, took a piece of chicken and left, soon returning to eat more, as guests sat in semidarkness and watched.

The Davises returned to the Pantanal later in their trip to spend a week in the northern part of the wetland at Jaguar Ecological Reserve. After their Pantanal visits, they spent three days at Chapada dos Guimaraes National Park to see spectacular scenery and green and red macaws. Before ending their trip on Oct. 3, 2003, they brought up to date the list of bird species they had seen during their 30 days in Brazil – 232.

This trip was not the first exotic vacation the Davises have taken. They have been on Earthwatch expeditions to study Lake Naivasha in Kenya, monkeys in Sri Lanka and wolves in India. While Lee Davis was a volunteer on an orangutan conservation project in Indonesian Borneo, Ron Davis carried out paleoecological research in nearby peat swamp forests.

They like Earthwatch, they said, because they can do important work, see all kinds of things they wouldn’t otherwise and get to know local people. One thing is sure: Another Earthwatch trip is in their future. They haven’t been to Australia yet, and would love to see it.

For those interested in planning an Earthwatch trip, the Web site is www.Earthwatch.org.

Ron and Lee Davis will give a talk, “Adventures in the Pantanal, a South American Wetland,” at 7:30 p.m. Wednesday, Nov. 3, at Fields Pond Audubon Center in Holden. Call 989-2591 for details.