‘Bear’s-eye camera’ reveals elusive Andean bear cannibalism and treetop mating

In the mountains of Peru, where ancient cloud forests meet the Amazon Rainforest, an Andean bear made scientific history. For four months, a camera collar captured the wild male’s daily life, revealing behaviors never before documented in the Southern Hemisphere’s only bear species, from treetop mating rituals to unexpected acts of cannibalism.

The study, published in Ecology and Evolution, provides a bear’s-eye view of life in one of South America’s steepest and wettest terrains and marks the first time this technology has been used on the species.

“For 15 years, I’ve been traveling up and down that valley and never seen a bear,” Andrew Whitworth, executive director of Osa Conservation and co-author of the study, told Mongabay. “So, the prospect of capturing a bear was quite insane. … These are just sheer walls of cloud forest.”

Ruthmery Pillco Huarcaya, a National Geographic Explorer and the study’s lead author, led the research team. She says her work to protect the Andean bears of Peru is inspired by the legends of her Indigenous Quechua heritage.

Guardians of the Andes

Andean bears also hold profound cultural significance in Andean communities. “In Andean Quechua culture, Andean bears are known as Ukuku or Ukumary. The Ukukus are mythical beings, half-human and half-bear,” Pillco Huarcaya told Mongabay in a text message. “I wish people knew that Andean bears are the guardians of the mountains and vital ambassadors for the conservation of cloud forests, their primary habitat.”

To better understand these mountain guardians, in 2023, the team deployed camera collars on three wild Andean bears (Tremarctos ornatus) in Peru’s Kosñipata Valley. The first two collars were pilot studies that used National Geographic’s CritterCam. However, the study is based on just one longer-term collar worn by a male bear for four months, revealing many behaviors scientists have never seen before.

The footage challenged long-held assumptions about Andean bears being solitary vegetarians. Instead, it showed them as social creatures, having both peaceful and aggressive interactions with other bears.

Love in the Canopy

During his four months under observation, the male bear engaged in two remarkable courtship periods. The first, a weeklong encounter in December 2023, documented something never before seen: Andean bears mating in the tree canopy. The bears were filmed coupling high above the ground in at least eight video clips. A second female encountered the male in March, though no mating was recorded.

“There seems to be these sort of very intimate moments when he’s with a female and they’re hanging out in the same tree, just looking at one another,” Whitworth said. While Andean bears have long been considered solitary, the footage showed the pairs remaining together for days at a time and sleeping next to each other, suggesting their social lives may be more complex than previously understood.

The bear’s agility in the canopy wasn’t limited to mating. The bear was also filmed feeding 20-30 meters [65-98 feet] up into the top of a Cecropia tree. “I remember being really shocked when we saw this,” Whitworth said. “These are fast-growing, very spindly, hollow trees that snap really easily, and we see this bear 30 m up feeding on seeds. Holy smokes!”

Bears will be bears

The footage also revealed that Andean bears are not purely vegetarians but have an omnivorous behavior typical of other bear species. Camera collars caught them eating insects and meat along with fruit, bromeliads and even stinging nettles.

In one surprising discovery, the collared bear was recorded feeding on the carcass of a woolly monkey (Lagothrix cana), the first documented case of an Andean bear consuming a primate. Nine video clips captured the sequence of events, showing the bear first with the monkey’s carcass on the ground before carrying it into the tree canopy, where the primate’s hand was clearly visible. The footage suggests the bear discovered the already-deceased monkey while foraging rather than hunting it.

Even more dramatic were two instances of cannibalism caught on camera. In mid-November 2023, just a month before his mating season, the bear was recorded feeding on a dead bear cub over three days, starting with the head and moving to the stomach.

In a second incident on New Year’s Day 2024, after a long journey crossing the Kosñipata Valley, the bear was filmed in the canopy consuming what appeared to be the partially eaten carcass of another small bear.

While cannibalism has been previously reported in Andean bears in Ecuador, this could be the first documented case of infanticide in Andean bears, a behavior known in other bear species. These videos suggest these bears may be more similar to their northern cousins than previously thought.

“When you look at everything that we’ve recorded,” Whitworth said, “you realize it’s just like any other bear.” This simple observation might be the study’s most profound finding, Whitworth said. Beneath the mystery and mythology, Andean bears are just bears being bears.

How to catch a bear

Collaring an Andean bear in Peru’s steep cloud forests required ingenuity and patience. The team used an “Iznachi trap,” essentially a large box with a guillotine-style door that drops when a bear enters to take the bait. But first, they had to get the trap into position.

“We had to design it where it was in panels that could be put on your back, and you could hoist these big metal panels out through these mountains,” Whitworth said. “It was pretty dangerous.”

Working with a local mechanic, they created a portable version the team could carry in pieces and assemble on-site. Each trap was connected to a satellite transmitter that would immediately alert researchers via email when triggered.

The process of actually catching a bear required careful preparation. “You don’t arm the trap at first; you kind of want them to just get used to coming in for the bait,” Whitworth said.

Using camera traps, the team spent a year identifying where individual bears hung out before attempting any captures. This allowed them to target specific animals while avoiding females with cubs. The trap’s design ensured only bears could trigger it. “It’s so heavy that pulling the prongs from this big door is actually real hard for an animal to do,” Whitworth said. “If a fox comes, they’ll nibble on the meat, but they’re not strong enough to pull it and trigger the trap.”

Once a bear is caught, the teams head to the field to immobilize it using a precise combination of drugs. During the immobilization, veterinarians conducted health evaluations and fitted a collar with GPS tracking onto the bear.

Tracking technology

The collars are designed to be released remotely via satellite, typically after about three months. The researchers wait until the bear is in an area where they think they can retrieve the collar, then send a signal to fire a release mechanism. However, the process isn’t always straightforward.

“The problem is that collar has been on the bear for a few months, and a bunch of gunk can just sort of keep it closed,” Whitworth said. “So sometimes you don’t find the collar in the place where the release went. It can take two or three hours to wiggle off, and the animal could have moved kilometers.”

Even after successfully tracking a collar’s location, retrieving it from the precipitous terrain proved its own adventure. During one recovery attempt, a swollen river separated the team from their quarry. The solution emerged from the community itself.

“Ruth hired a bunch of the local people and we built a makeshift bridge to sort of scramble over this raging torrent,” Whitworth said, highlighting how local knowledge and collaboration often proved crucial to the project’s success.

After retrieving the collar, researchers anxiously waited to see if the data were successfully recorded. Despite these challenges, the team has had been largely successful in recovering their equipment. Across their broader mammal research program, they’ve retrieved 19 out of 20 collars deployed on various species.

This high recovery rate helps justify the steep cost of the technology, around $5,000 per camera collar. The study authors argue the investment is worthwhile when compared with the total cost of bear research.

The bigger challenge, Whitworth noted, is making this technology accessible to researchers in tropical regions where many poorly understood species live. He said that financial support from National Geographic and Rolex allowed the team to take risks on expensive technology, “but for a lot of researchers in the Global South, those risks are unattainable unless they can get access to the resources.”

Beyond the technical and financial challenges, the footage offered something unique: a glimpse into how an Andean bear experiences its world. Whitworth describes the wonder of seeing from a bear’s perspective, noting that the bear would sometimes stop at a vista and look out over the landscape, much like humans do on a hike.

“He’ll be walking and then all of a sudden, he’ll just stop in some beautiful part of the Andes and look out over the river and the valley,” Whitworth said. “He’s probably smelling and looking at his surroundings, but you get the idea that he’s seeing the land, in some respects, how we see it. It’s pretty incredible.”

Seeds of survival

However, understanding Andean bear behavior isn’t just amusing. These large mammals play an important role in the ecosystem, eating seeds and then dispersing them over large distances. This service helps maintain the immense biodiversity of the cloud forest, an ecosystem critical to the water cycle of the entire Amazon Basin.

Yet the bears’ vital role in the ecosystem is at risk. Listed as threatened by the International Union for Conservation of Nature (IUCN) Red List, there are estimated to be fewer than 20,000 Andean bears left in the wild.

The species faces pressures from multiple directions. As the climate becomes hotter and drier, their habitat is pushed upward. At the same time, human activities like farming are moving in from above, leaving the bears less room to roam.

“Sadly, I don’t see things improving for Andean bears anytime soon,” Whitworth said. “There are some scary predictions about cloud forest loss under current climate warming scenarios.”

This squeeze on their habitat forces bears to adapt their movements and behavior. They rarely stay within a national park, instead passing through multiple protected areas and community lands—sometimes raiding crops or in very rare cases preying on livestock. This can lead to retaliatory killings by local people. Camera footage paired with GPS tracking can help researchers and communities understand why bears are going to community lands, what risks they take, and perhaps how to avoid conflicts.

Community conservation

In response to these challenges, Pillco Huarcaya’s team is also working to expand their community engagement efforts, transforming their field station into what Whitworth called a “community conservation campus.”

“My work with children has had a significant impact on how the community views Andean bears,” Pillco Huarcaya said. “Through our ‘Conservation Ambassadors’ program, children visit the Wayqecha Biological Station to learn about the bears and the cloud forest. Many of them didn’t know about Andean bears before, and now they see them as friends that need to be protected.”

Despite the challenges, Whitworth said he remains cautiously optimistic. The behaviors captured by the camera collars demonstrate the bears’ intelligence and adaptability. “If there is a species that can change fast and learn quickly,” he says, “it’s a bear.”

Citation:

Pillco Huarcaya, R., Whitworth, A., Mamani, N., Thomas, M., Condori, E., (2024) Through the eyes of the Andean bear: Camera collar insights into the life of a threatened South American Ursid. Ecology and Evolution 14(12) doi: 10.1002/ece3.70304

This article by Liz Kimbrough was first published by Mongabay.com on 6 December 2024. Lead Image: Andean Bear (Tremarctos ornatus) in Parque Nacional del Rio Abiseo, Peru. Image by Pedro Peloso courtesy of National Geographic and Rolex Perpetual Planet Amazon Expedition.

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