Nov. 21 (UPI) -- An indoor cat who escaped from his Ohio home was reunited with his owner after surviving 18 months in the wild.

Richard Campbell, a retired Miami University professor, said his cat, Calvin, escaped from his Oxford home while family members were visiting in April 2021.

Campbell said Calvin had been an indoor cat ever since the feline and his brother were rescued from a tree as kittens in 2017.

There was no trace of Calvin until this fall, when Susan Prochaska, a fellow retired professor, spotted a cat wandering loose on the edge of the Miami University Natural Areas.

"Over approximately two weeks, I would go twice a day and call the cat and provide food and water," Prochaska told the Oxford Journal-News. "Eventually, the cat started to come closer but would disappear each time after he ate."