Located in the western city of Wuppertal, Netzwerk Igel e.V. is one of a shrinking number of nonprofit organizations in Germany that cares for sick and injured hedgehogs. It takes in between 400 and 500 hedgehogs every year and provides them with food, medicine and shelter as they recover.

The hedgehog species native to Germany is the brown-breasted hedgehog (Erinaceus europaeus). These animals usually inhabit open landscapes, but farming and pesticide use often push them out of their natural habitats. It's common to find large populations in backyards or on the fringes of human settlements, which increases their risk of getting injured.

Monika Thomas, the founder and chief of Netzwerk Igel, describes the rescue center as a "hospital for hedgehogs." The animals are nocturnal animals; spot one during the day and it's likely either to be sick or hungry. Every day, Thomas receives an average of 10 to 15 calls from people who have seen hedgehogs that might need help.

Contrary to other species that might flee when faced with danger, hedgehogs choose to curl up into a ball and remain motionless. This doesn't harm them when they are in the medical bay at the rescue center, but it's dangerous when they are in the wild or on a busy road. "They are at the mercy of what comes next," said Thomas.

The most serious injuries occur during the summer. Some hedgehogs arrive with wounds caused by garden tools or by cars. Others fall into swimming pools or are attacked by dogs. Robot lawn mowers are particularly dangerous. The sensors in some of them are insufficient to detect the presence of small animals.

Conservationists estimate the hedgehog population is reducing at an alarming rate. The animals only breed once a year; less than half the litter is likely to survive the first winter. Baby hedgehogs need to weigh more than 400 grams (almost a pound) by fall to make it through hibernation. Each winter, the rescue center becomes a sanctuary for little hedgehogs who didn't reach that weight in time.

Most hedgehogs in the center arrive with injuries to their head, legs or paws, but some come in with internal injuries, too. These are more difficult to detect and only become noticeable after observing how the animal behaves post-trauma. That's the case with the hedgehog in this photo: It was diagnosed with neurological damage and is now slowly recovering in the "intensive care unit."

Thomas founded Netzwerk Igel in 2006 after inheriting a little money. Now the rescue center runs entirely on donations. It currently houses around 120 hedgehogs. Sometimes it gets busy for the volunteers ― another sanctuary in the region closed recently. The donations the center receives are enough to hire only one person full-time. "We don't receive any municipal support," said Thomas.

Once they have recovered, the hedgehogs are returned to the wild — most of them to the places where they were found. When that's not possible, Thomas and her team look for a new spot in and around Wuppertal. They rely on the support of local residents and hope in the process to boost hedgehog protection: "We explain to them how to arrange their garden with dead wood and leaves," she said.