You don't have to go too far to encounter nature in Berlin. And I don't mean simply riding the S-Bahn to one of the city's numerous lakes in summer, or putzing around its vast parks after work. I'm talking about those special moments when you stumble out of a bar at 3 a.m. and spot a sleek fox scurry across a puddle of soft light falling from a streetlamp before it dives into the closest shrub.

Or perhaps you've been lucky enough to cross paths with a wild boar in a nearby forest - or unlucky enough if you happen to clash in a residential neighborhood. These tusked creatures roam the city by the thousands and have given Berlin its title as the "wild boar capital" of Germany.

Berlin's unique political situation is partly responsible for the continued proximity of its wildlife. Due to its division there has always been plenty of abandoned buildings, and not only for homo sapien squatters - these spaces make perfect dwellings for animals.

A city of bridges

Berlin's skyline is dotted with bridges - the Oberbaumbrücke , the Weidendammer Bridge, the Kaisersteg , and the pedestrian Gustav- Heinemann - Brücke all tell a part of Berlin's reconstructive history.

Recently, Berlin erected another practical overpass - this one for squirrels.

Similar to a wildlife crossing, a squirrel bridge is a construction that allows small animals, especially squirrels and martens, to safely transverse busy roadways. Before last March, the idea would have met with twisted-up faces, perhaps even giggles.

The idea may still be giggle-worthy, but it's been set to the test. This winter, animal rights organization Aktion Tier installed the capital's first squirrel bridge in the district of Treptow-Köpenick, on the traffic-stricken Müggelseedamm, a tree-lined road that borders the Müggelsee lake in the southeast Berlin.

Organizers first found the perfect location - then visualized the bridge

The second squirrel bridge in Germany - the first can be found in the central town of Vlotho - is actually a thick length of plastic rope. It starts nine meters up and extends 21 meters between two trees on either side of Müggelseedamm. The branches of the adjacent trees do not touch, so squirrels are forced to use the road - hence the need for the squirrel bridge.

"We have more wild animals in the city than in nature," said Ursula Bauer of Aktion Tier. "They are living together with us and we have to deal with it. The traffic is very dangerous for them - for the hedgehogs, for the birds, and of course for the squirrels."

But as Bauer explained, such a simple idea is never that easy to implement in Germany, where every branch (excuse the pun) of production is regulated.

According to Bauer, they first had to find the owner of the strip of land where the trees are rooted. Then it took months to find a certified tree climber to install the squirrel bridge, and more time to find the proper insurance to cover every possibility.

And there's one more delightful feature: Wooden boxes filled with nuts are fastened at each end of the rope to lure the squirrels.

"Animals are very particular. They might not use a rope that is not exactly in the direction that they want to cross," said Bauer. "You have to observe the area and build the rope where they want to cross the street."

Which squirrel wouldn't be motivated by a mound of nuts?

The world's narrowest bridge

Bauer was initially approached by Henrik Zwadlo from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, which is located directly at the site of the squirrel bridge.

Ursula Bauer (left) and Henrik Zwadlo hope to see fewer squirrel deaths

"He saw so many squirrels being killed in the street," said Bauer. "Nearly every month he saw one die."



After witnessing one squirrel death too many, Zwaldo set out to make a change - and found the inspiration he needed from similar initiatives. The first squirrel bridge was documented in 1963 in Longview, Washington; it was officially called The Nutty Narrows Bridge. More complex than a rope, the mini suspension bridge - dubbed the "World's Narrowest Bridge" - spans 18 meters and is made of aluminum piping covered with a retired firehose. The total cost for the bridge was $1,000 (720 euros).

Others have followed. ABC news reported in 2010 that the state of Arizona was intent on spending $1.25 million to build bridges for endangered squirrels over a mountain road to prevent more roadkill. Squirrel bridges can also be found in the UK, Belgium, France and the Netherlands.

One green spot to the next

"The difference between other cities and Berlin is that elsewhere animals usually stay in the periphery, while in Berlin they can be observed in the city center as well," explained Susanna Hertrich, a Berlin-based visual artist. Her recent installation, "Berlin Wild Life," explores cross-species cohabitation between humans and wild animals.

Hertrich says animals can move relatively undisturbed because of Berlin's many parks that allow them to jump from one green spot to the next. "Due to its history, Berlin offers fallow lands and abandoned spaces in its center, where other cities tend to be fully developed," she said. "These places of course make perfect settlements for animals, like foxes or raccoons.”

Or even rabbits. The so-called death zone, the no man's land along the Berlin Wall, experienced a drastic influx of wild rabbits breeding and living in bunny utopia. The German-Polish documentary, "Rabbit a la Berlin" (2009), tells this unique part of Berlin history as an allegorical study of a totalitarian system.

Hertich's "Berlin Wild Life" project focuses on the interactions between humans and animals

According to Hertrich, the best time for animals in Berlin was in the early 1990s after the Wall was destroyed and largely removed. "Urban development in East Berlin had not yet fully begun, and walls, wires or hidden land mines no longer interrupted animal migration from one part to the other part of the city," she explained. "The animals were able to find a large number of unused plots, derelict buildings and abandoned spaces. Such places can of course still be found, but increasingly less so!

New animal-human architecture

Since the squirrel bridge was erected, Ursula Bauer says she hasn't actually spotted any squirrels using it yet. But that doesn't mean they're not - there haven't been any more reports of dead squirrels on Müggelseedamm. Aktion Tier is considering installing a small camera to see if their efforts have paid off.

So far, there's been no opposition to the squirrel bridge on Müggelseedamm. In fact, it's even sparked peculiar excitement. Bauer recalls little known politicians coming out of the woodwork at its grand opening to have their photos taken with the mighty rope.

There is also talk of installing more squirrel bridges in Berlin, perhaps on Heerstrasse. But Bauer is wary - she has first-hand experience with Germany's red tape. "It's a big street, and the insurance might not cover such a long rope."

As Berlin continues to grow, Susanna Hertich sees a possibility for animals to be actively incorporated into urban planning.

"[If] new building plans took the animals' needs into consideration, then gentrification would not necessarily be an interruption," she said. "In fact, this could be a very interesting starting point for new forms of animal-human architecture."