In the forests of northern Mato Grosso, Brazil, roads slice through the canopy and force arboreal animals down to dangerous ground level. Simple rope bridges strung above the traffic now give primates and other species a safer route. Eight of these structures went up in Alta Floresta in 2024, and camera traps have since logged an extraordinary record of use.
Early Results Exceed Expectations
The eight bridges produced 15,000 documented crossings in just 15 months. No roadkill occurred at the monitored sites during that period. Researchers watched animals approach, hesitate, and eventually commit to the crossing, sometimes after repeated visits. Different species moved across the ropes in their own ways. Some walked steadily along the thicker lines while others swung or used their tails for balance. The multi-layered design accommodated these varied styles without forcing any single method.
Primates That Took Their Time
Six primate species adopted the bridges. Black-faced black spider monkeys, Schneider’s marmosets, and the critically endangered Alta Floresta titi monkey all appeared on camera. Tufted capuchins waited seven months before using one structure, showing that habituation can be gradual. Footage captured both successful passages and cautious retreats. The data helped refine placement and rope arrangements for future installations. Community input from earlier projects guided many of these choices.
Lessons From a Longer-Running Effort
A separate set of 32 bridges installed along the BR-174 highway in 2021 offers additional perspective. Members of the Waimiri-Atroari Indigenous community helped choose the sites. Roughly 1,250 primate crossings have been recorded there over five years, supplying practical knowledge about which designs hold up best in daily use. Roads fragment habitats and limit gene flow between groups. The canopy bridges address that isolation directly by keeping animals off the pavement. Continued monitoring will show whether the structures support longer-term population health.
What the Numbers Reveal
The combined projects demonstrate that low-cost rope solutions can deliver measurable protection. Camera records now include both frequent users and first-time crossers, painting a clearer picture of how wildlife adapts to human infrastructure.
- 15,000 crossings recorded with zero roadkill at the new sites
- Eight bridges in Alta Floresta plus 32 along BR-174
- Six primate species documented, including a critically endangered titi monkey
- Habituation periods range from weeks to seven months
These bridges show how targeted, low-impact interventions can reconnect fragmented forests. As more roads appear across the Amazon, similar designs may offer a practical way to reduce wildlife losses while keeping traffic moving.
