*** Update ***
Fur and skin samples have been collected from the site (not where the photograph was taken - a second sighting), and has been given to Biologists at
Southern Illinois University for analysis.
OAKLAND - State biologists on Tuesday began investigating the second reported mountain lion sighting in the area in a week.
...
On Tuesday, Oakland resident Kelvin Higgins provided a sample of fur and possibly some skin to state biologists. He said a big cat shed the fur while
grooming itself on a snowy rock in his wooded backyard in April.
"I'm not 100 percent sure it was a mountain lion, but it was a big cat, believe me," Higgins said.
...
In that incident, an unnamed resident provided a grainy photo of what appeared to be a large cat to the Department of Inland Fisheries and Wildlife.
Latti said the photo was inconclusive.
The Oakland sighting is different, according to state biologist Keel Kemper, who said the sample appears to include both hair and flesh, and is large
enough for DNA testing.
"This does not look like deer hair, to be honest with you," Kemper said.
Source
So, it seems there is a big cat in Maine. Only a matter of time before we know what it is.