River Road in Pennsylvania has been closed by the National Park Service to make way for mating amphibians.

During rainy seasons, amphibians such as frogs and salamanders frequent the road to search for potential mates. The park service said vehicles that pass along the road might squash them while they are doing their business at night.

"They're actually coming. If you can see, behind us is the forest, and that's where they spend their winter, and then they come out of those grounds just when the conditions are right," said Park Ranger Kathleen Sandt in an interview with WNEP.

The amphibians had to cross the road to get to the moist breeding pool where they will fertilize their spawn. The road will be closed on nights when the weather and temperature is just right for them to start their breeding activities. It will reopen at 6:30 a.m.

"This year, we had our first road closure in February, which we've never done before," Sandt added. Usually, breeding season starts at mid-March through mid-April.

Associated Press reported that the public can get a glimpse of their activity. But they are advised to wear light-colored clothing and bring flashlights. Since vehicles are not allowed in the area, they must park their car at the headquarters before doing some walking in the road where the amphibians are crossing.

"Closing the road to vehicles not only protects the amphibians," said Superintendent John J. Donahue in a statement published on the National Park Service website. "It also offers a rare opportunity for the public to observe one of the most unique natural occurrences in region."

The National Park Service had been closing the road since 2003 to protect and encourage the breeding of the amphibians.

Endangered Species International notes that overall, one in three amphibians are at risk of extinction. Their population has been reduced mainly because of human activities such as habitat destruction and climate change. At least 120 known species had completely disappeared over the last few decades.