While many New Yorkers spend their days high above the ground, most are gazing down at the wildlife from Midtown office towers, not a rainforest canopy. But one Harvard-trained biologist, Mark Moffett, often finds himself in the clouds, in 150-foot trees towering over the Amazon River.

Mr. Moffett, who is also an award-winning National Geographic photographer and a research associate at Berkeley’s Museum of Vertebrate Zoology, spoke about his work this week at the Cornelia Street Cafe. A student of entomologist E.O. Wilson, he earned his Ph.D. studying army ants in Asia. Once a month, city slickers get a dose of nature when they descend the restaurant’s stairs for such “Entertaining Science” lectures hosted by a chemistry professor from Cornell University, Roald Hoffman.

On Sunday, the evening began with a performance by composer Phoebe Legere, who presented the history of life on earth – set to music. She belted out lines such as “I’ve got the evolution blues” and “It took a million years to make a man out of a monkey.” Her colorful commentary included asides such as this defense of bacteria: “We try to kill them, [but] they’re just trying to feed their families.”

Mr. Hoffman then introduced Mr. Moffett and described him as bearing a closer resemblance to Indiana Jones than anyone else he has met. After all, during a trip to Colombia, Mr. Moffett used tribal blowguns in self-defense against the smugglers he encountered, and found himself caught in stampedes of both Asian and African elephants in the same week, adventures he recounted in the pages of Natural History magazine.

While certainly no less dangerous than the above episodes, much of his research is performed from more tranquil vantage points: in the upper branches of trees.

He has climbed trees in more than 40 countries. But how? Mr. Moffett described myriad scaling methods. One involves placing a strap between one’s feet and inching up the trunk. A Robin Hood-like method involves shooting an arrow over a branch. Fishing line is tied onto the arrow, enabling cords and ropes to help the climber. A third way – “at the other end of the budget” – requires large industrial cranes, from which researchers dangle in gondolas.The major difficulty with this method, he said, is getting the crane into the rainforest in the first place.

The talk began with a slide show. Friends, such as a Swiss scientist, were captured in precipitously high perches. The Swiss man could have been “mistaken for an insane telephone repairman,” Mr. Moffett said. Another photo pictured Darwin expert Frank Sulloway, who packs eight teddy bears for a trip and is known to take them out during meals. In one slide, a scientist collected green tree vipers, put transmitters on them, and then followed their movements.

Exotic creatures filled the screen. Mr. Moffet has photographed ants in Borneo that join together to form a living bridge that stretches from one tree to the next, allowing fellow ants to crawl across.

“What’s this?” he asked of an animal he found in Peru. “A tribble,” an audience member replied, referring to a furry space creature from a “Star Trek” episode. “No,” Mr. Moffett replied, describing his unidentified find as a “cotton-candy caterpillar.”

Deadly creatures intrigued the audience. Tarantulas were seen being eaten by Indians in Venezuela. They pick their teeth with tarantu la fangs, Mr. Moffett said. He also showed a slide of a herpetologist friend who was bitten by a deadly krait snake on September 11, 2001, and died the next day.

Mr. Moffett later told the Knickerbocker about the time he inadvertently sat on one of the world’s most deadly snakes, the fer-de-lance, in Peru. He managed to land in such a way that the snake was unable to bite him. The lesson, he said, was: “It’s important to sit on a venomous snake in the correct way.” Mr. Moffett has also photographed a poisonous frog, the Latin name of which contains the word “terribilis.” One touch of an arrow on the frog’s back is “good for a year,” he told the Knickerbocker.

Mr. Moffett has tried to understand the ecosystem of the aerie. For different creatures, he told the audience, the rainforest canopy poses a different kind of labyrinth. One finds routes used by animals that become well-beaten pathways. One slide showed a monkey that took a wrong turn and got stuck on a branch. In another, jumping spiders traversed trees in ways that are almost “smarter than lions, tigers, and bears.” He said that scientists have shown that if a jumping spider is raised alone in captivity, it doesn’t develop maneuvering skills: Placing sticks in its cage encourage dexterity.

Animals aren’t the only things scurrying about in the wild. “Some plants are quite mobile,” Mr. Moffet said. They crawl around like a snake, “growing in front and dying behind, looking for a place to bask.”

Mr. Moffet asked the audience how trees manage to grow on sheer slopes. The answer is asymmetrically. The side facing the sun grows quickly compared to the side facing the slope in shadow. Sometimes this imbalance causes a tree to topple over.

Darwin investigated how vines climb trees up from the bottom. But Mr. Moffett explained how plants grow from the top down. He gave an example of “a plant in a hurry.” After a bird drops a seed on a tree branch, a plant called a strangler fig shoots roots downward into the water table. Even though rainforests are damp, moisture drops from the tops of trees, often leaving the canopy quite arid. He said cacti are very common in trees of South America. The strangler fig eventually envelops the tree, suffocating it, blocking its sunlight, and competing for nutrients in the soil. It remains in place after the host tree dies and rots.

Present at the lecture was neurologist and author Oliver Sacks (“The Man Who Mistook His Wife for a Hat”). Two actors were also present: Jeremy Lawrence, who portrays Einstein in “Albert in Wonderland” on February 22 at Cornelia Street Cafe, and Cornelia Street Cafe’s co-founder, Robin Hirsch, who performs at the Leo Baeck Institute in late March in a one-man show about his coming-of-age as the son of German Jews in postwar Britain.

What’s left for Mr. Moffett to explore? He has already been part of a team that ascended the world’s tallest tree – a 365-foot redwood. He hopes to explore the world’s largest cave opening (100 yards in diameter) and also hopes to further travel and explore Africa.