A 2011 paper about cougar sightings and evidence in Ontario has this photo in it. Not much detail is given about the photo, but the author states that there were 51 credible “black cougar” or “black panther” sightings in the area between 1991 and 2010. Given the fact there never been a documented melanistic cougar, the author suggests these sightings are exotics, either jaguars or leopards. Link to the paper https://www.canadianfieldnaturalist.ca/.../1194/1187/4744