A large black snake slithered out onto the Belfast Rail Trail on Oct. 10, startling people who were walking, jogging and biking along the popular path. Foreign to Maine, the 3-foot-long reptile was a black rat snake, and it likely arrived in the area as a stowaway. Each year, people report a handful of nonnative reptiles and amphibians spotted crawling and slithering through the Maine wilderness — from boa constrictors to tiny tropical lizards — said Derek Yorks, a biologist with Maine Department of Inland Fisheries and Wildlife that specializes in reptiles and amphibians. Some of these creatures are pets that escaped or released by their owners, while others are stowaways, entering the state by vehicle or in shipments from far away places. “There are a lot of ways small reptiles and amphibians can hitch rides,” Yorks said.