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Andean bears (Tremarctos ornatus), well-recognized for their cultural depiction in the character “Paddington,” are unique mammals native to the Andean regions stretching from Bolivia to Venezuela. Classified as vulnerable on the IUCN Red List, these bears exhibit intriguing feeding behaviors that could play a crucial role in their conservation. Rather than targeting livestock, which has historically led to conflicts, Andean bears are selective foragers, seeking optimal food sources to enhance their nutritional intake. Insights from these behaviors are detailed in a recent study published on December 18 in the journal PLOS ONE.
Commonly referred to as “spectacled bears” due to distinctive white facial markings, Andean bears are typically arboreal, spending a significant portion of their lives climbing trees. These midsize bears measure between four and six feet in length. Despite their size, they tend to be shy and reclusive, complicating efforts to study them in their natural habitat. Their main risks include habitat deterioration, climate shifts, as well as human-wildlife conflict, particularly with ranchers. While occasional predation on livestock has been reported, research indicates that such incidents may be less frequent than believed.
A noteworthy component of their diet consists of bromeliads, a flowering plant family that encompasses everything from commonly known pineapples to less colorful varieties like Puya raimondii. Understanding the foraging habits and dietary preferences of Andean bears across different environments remains a challenge, as their habitats encompass a variety of ecological zones, including cloud forests and grasslands.
“Andean bears consume a diverse range of over 300 plant species,” explains Nicholas Pilfold, a co-author of the study and a conservation scientist at San Diego Zoo Wildlife Alliance. “This diversity underscores their significant role in the seed dispersal of the cloud forest ecosystem.”
The recent study, involving researchers from Peru and the United States, focused on two bromeliad species—Puya leptostachya and Puya membranacea—that inhabit high-altitude grasslands known as “puna” around Manu National Park in Peru. The research team mapped the locations of these plants and documented instances of bear feeding, indicated by signs like excavated or half-eaten stalks.
Utilizing trail cameras, the researchers confirmed the presence of Andean bears at surveyed bromeliad patches, which constituted only 16.7 percent of the available sites. Surprisingly, the bears showed a marked preference for foraging during the dry season, when younger and more digestible plants become more prevalent.
The bears favored P. leptostachya growing on steep, east-facing slopes at the forest’s edge, and they were seldom seen foraging beyond park boundaries where livestock grazed.
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“I was impressed by the selectivity displayed by the bears when choosing which bromeliads to consume,” remarks Pilfold. “They specifically target the base of the stem of the youngest plants, and they are willing to scale high and steep terrains to locate them.”
The findings indicate that Andean bears preferentially forage in areas with minimal human interference. Although they generally sidestep locations with livestock, they are found foraging in regions that were grazed several decades prior. This adaptability in their foraging practices might enable them to reclaim previously occupied territories, though targeted conservation initiatives will be essential to assist in their recovery.
“Our study highlights the importance of habitat protection from human encroachment, which can significantly benefit Andean bears and create more spaces for their feeding,” concludes Pilfold.
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