Pyrenees: 108 bears counted, the population is increasing but the shadow of inbreeding looms

First, a striking figure: at least 108 brown bears are expected to be identified across the Pyrenees mountain range by 2025, according to the annual report from the French Office for Biodiversity published this Thursday, March 26. That's one more than in 2024, and the long-term trend remains upward, with an average annual growth rate estimated at +11,53% between 2006 and 2024.

The monitoring relies on well-established methods, including genetic analysis of hair and scat samples, and 2024 saw at least six litters for a total of eight cubs. This increase didn't happen by chance: it's a continuation of the reinforcement efforts begun in the 1990s, with the introduction of bears from Slovenia, following the collapse of the local population.

A digital success, a genetic weakness

But behind the rising curve, the report offers a less reassuring warning: genetic diversity is declining and inbreeding is increasing. The French Office for Biodiversity (OFB) refers to "low genetic diversity" and emphasizes that the initial results of a state-commissioned study point to a negative effect from the earliest stages of life: smaller litters, reduced dispersal, and lower survival rates among cubs born to the most inbred mothers.

On the ground, the issue remains volatile: cattle and sheep farmers denounce summer predation when their herds are moved to high pastures, while pro-bear associations regret the lack of decisions regarding new releases. One of these associations, Pays de l'Ours-Adet, describes the population as "genetically vulnerable" due to an insufficient number of founder bears. The species' presence persists despite a slight decrease in the area it occupies over the past two years, and the full results of the state study are expected by the end of the year—a crucial moment to determine whether the Pyrenean bear population is growing on a solid foundation or in a precarious balance.