These 50 metre-high rope bridges are helping sloths in Costa Rica survive deforestation

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Zoologist Rebecca Cliffe knows some people see sloths as "boring, lazy animals," but she believes there's something special about their slow pace.

"I always describe it a bit like trying to swim through a lake of Nutella," the sloth expert and enthusiast told The Current's Matt Galloway. "Everything is in slow motion, and they're just very peaceful, lovely creatures that don't require much for survival."

What they do require are trees, in dense proximity with each other. Sloths spend most of their lives in trees high above the ground, safe from dangers such as cars and electricity lines.

They also use leaves for shade and sustenance, and vines and branches to travel.

"Sloths can't run and they can't jump, so they really need trees to physically connect and overlap," Cliffe said.

For years, this wasn't an issue for most sloth populations. But as expanded land development has cleared patches of rainforests in places like Costa Rica, sloths are being forced to move along the ground more often, leaving them susceptible to attacks and even death.

"I first came [to Costa Rica] 13 years ago and it was a completely different place," Cliffe said. "It was wild and the roads were single lane and the trees would connect over the road — and in the last 10 years, development has gone completely out of control."

That's why Cliffe and her non-profit, The Sloth Conservation Foundation, focus on saving not just sloths, but also their habitats. They work with communities that are developing land to help keep sloths and their needs in mind.

"I think what's important is that people do [economic development] in the right way and we do it with the wildlife in mind," she said. 

Special sloth bridges

One way Cliffe and her crew are doing this is by constructing special bridges for sloths to travel on. 

"These are essentially wildlife bridges that help sloths get from tree to tree in urban areas and [avoid] … having to come down to the ground," she said.

Cliffe said these bridges are remarkably simple: each bridge is made of a single string of rope, tied between different trees at alternating heights. 

These ropes can go as high as 50 metres in the air — and some of them even cross over buildings and houses.

"I have a tree-climbing team, and … they climb up and they install them. They just tie them around the branches," she said. 

Although ropes aren't natural to sloths, Cliffe said they're accustomed to climbing on thin structures like vines. After some initial hesitancy, "as soon as they realize that this structure is safe, then they climb on it," she said.

"If it's there, they will use it once they trust it."

Cliffe said almost 30 other species of animals have also used the bridges so far, including monkeys and lizards.

"My favourite was a tree frog," she said. "A little frog hopped along the rope, all the way from one tree to the other."

A win-win for coexistence

Cliffe is aware that human expansion into wild places will not stop. But, she said the key moving forward is to expand in ways that will allow wildlife and humans to coexist peacefully.

This will require some flexibility on humans' part, but she said work is being done to keep animals like sloths in mind, including by governments.

Last year, the government of Costa Rica announced that both two-fingered and three-fingered sloths will become the national symbols of the country. 

Cliffe said this announcement gives sloths certain legal protections, including ensuring the conservation of sloths in Costa Rica and implementing aerial wildlife crossings on national routes.

It also benefits the country's tourism industry, according to Cliffe. She said Costa Rica's tourism industry generate billions of dollar every year, and that's in part to the sloths.

"[Tourists] want to see sloths, and they look on Google and Costa Rica is the place to see sloths, so everyone's coming here to see them," she said.

Cliffe said the work being done to protect sloths and their habitats is a win-win for everyone involved, from local Costa Rican communities expanding their land to the sloths who use the bridges to cross the treetops.

"It brings wildlife to their property, so they get to live amongst nature ... [and] the sloths are winning. Everybody's happy," she said.

Written by Mouhamad Rachini. Produced by Arianne Robinson.