University of São Paulo Study Reveals Critical Prey Scarcity Is Driving Jaguars Toward Extinction in Protected Forests

University of São Paulo researchers found that jaguars in the Atlantic Forest are starving as human access leads to the overhunting of their primary prey.

By: AXL Media

Published: May 1, 2026, 11:37 AM EDT

Source: Information for this report was sourced from Earth.com

The Hidden Crisis of Prey Depletion

While habitat destruction and direct poaching are widely recognized as the primary threats to large predators, a more insidious problem is unfolding within the Atlantic Forest. New research led by Professor Katia Ferraz at the University of São Paulo suggests that jaguars are effectively starving to death in areas where they should be most secure. The study indicates that even within protected national and state parks, the populations of medium and large mammals—the jaguar's essential food source—have dropped to alarmingly low levels. This "empty forest" syndrome means that while the trees remain standing, the functional food web required to support a top predator has collapsed.

Disparities in Forest Biomass and Predator Survival

To quantify the severity of the food shortage, scientists deployed camera traps across nine separate protected areas to monitor the abundance of key species like agoutis, peccaries, and deer. The field data revealed a staggering disparity in prey biomass across different regions of the forest. In the "Green Corridor" zones, prey biomass was measured at approximately 638 kilograms, providing a stable environment for jaguars to thrive. However, in coastal areas such as the Serra do Mar, that figure plummeted to a mere 8.2 kilograms. The researchers noted a consistent pattern: where the prey base is limited, jaguar populations are either extremely small or entirely absent.

Human Access and the Impact of Subsistence Hunting

The decline of prey species is directly correlated with how easily humans can enter protected territories. Areas characterized by flatter terrain or proximity to urban centers and villages show the lowest availability of prey. This suggests that illegal hunting for bushmeat is the primary driver of the decline. Professor Ferraz emphasized that there is a direct link between human pressure and the feline's survival; when people enter the forest to hunt for meat, they strip the ecosystem of the biomass needed to sustain a predator, creating a secondary pressure that is often overlooked in traditional conservation models.