New research indicates that Andean bears strategically choose optimal foraging spots and plants to enhance their nutrition while steering clear of livestock. This study, set to be published on December 18, 2024, in the open-access journal PLOS ONE, was conducted by Nicholas Pilfold and his team at the San Diego Zoo Wildlife Alliance in California, U.S.
Andean bears, often referred to as ‘spectacled bears’ due to the distinctive white markings around their eyes, are native to the Andes mountains. The International Union for Conservation of Nature (IUCN) lists them as vulnerable, facing threats from habitat destruction, climate change, and human-bear conflicts. A significant portion of their diet consists of flowering plants known as bromeliads; however, there has been limited understanding of their foraging habits and food choices in the diverse cloud forest and grassland environments where they live.
Researchers surveyed two species of bromeliads, Puya leptostachya and Puya membranacea, found in the high-altitude grasslands termed ‘puna’ within and around Manu National Park in Peru. They documented the locations of each plant and noted any signs of Andean bear consumption, characterized by stalks that were dug up or partly eaten, which indicates the bears’ feeding activities.
Using trail cameras, the presence of Andean bears at these surveyed locations was confirmed. The findings revealed that bears were foraging in only 16.7% of the available bromeliad patches. They showed a preference for foraging during the dry season when young, tender plants were accessible, as these are easier to digest and provide better nutrition. Specifically, Andean bears favored P. leptostachya plants located on steep, east-facing slopes at the edge of the forest within the puna grasslands, and they avoided areas outside the national park where livestock, such as cattle, are grazed.
The study indicates that Andean bears purposefully seek out bromeliads in areas they perceive as safe from human activities. While they steered clear of directly grazed areas, they did forage in locations that had been previously grazed by livestock decades earlier. This adaptability might allow them to quickly recover lost habitats with appropriate conservation strategies. The authors emphasize that high-altitude grasslands adjacent to cloud forests are vital habitats for Andean bears, and conservation officials should evaluate the effects of livestock on this crucial ecosystem.
According to the authors: “By utilizing the largest collection of field data to date on the feeding habits of Andean bears in high-elevation grasslands, we discovered that these bears actively select specific food resources in these areas, highlighting their nutritional significance. Additionally, we noted that Andean bears tended to avoid regions affected by livestock, but the abandonment of livestock grazing allows these grasslands to revert to the preferred habitat of the bears relatively quickly.”
