Overhead rope ladders saved endangered monkeys from road deaths in the rainforest of Brazil.

Wild animals have been observed using specially constructed rope bridges to cross the busy RS-040 highway, which connects the Porto Alegre Metropolitan Region to the coast of Rio Grande do Sul, without risking their lives.

The crossings were installed starting in October 2022, following studies by the Federal University of Rio Grande do Sul that identified areas with high wildlife traffic and frequent collisions.

Footage shows hedgehogs, brown howler monkeys, and white-eared opossums moving along the suspended walkways high above the road.

The structures are connected to the surrounding treetops and supported by concrete poles.

The bridges were introduced to protect the endangered brown howler monkey and other species, while also improving road safety.

Since their installation, reports of collisions with wild animals have nearly dropped to zero.

Between September 2024 and May 2025, over 4,000 mammals used the crossings, including 1,902 hedgehogs, 1,335 brown howler monkeys, and 220 white-eared opossums.

Luis Fernando Vanacor, CEO of the Gaucha Highway Company, said the results demonstrate the project's success, noting that animals are 'no longer at risk of being run over' and now cross safely.

The brown howler monkey (Alouatta guariba) is a key species due to its local and global threat of extinction. The Northern brown howler subspecies is particularly vulnerable, with habitat loss forcing it down from trees and into dangerous contact with roads, hunters, and domestic dogs. It is estimated that only around 250 individuals remain in the wild.

Officials said the walkways not only reduce serious traffic accidents caused by wildlife collisions but also help reconnect fragmented forest habitats.