Big canine for sure. Toes are kinda close together and you can't see any evidence of the nails contacting the ground. Not sure where your mom lives but I would bet very large domestic dog. But of course I could be wrong.

Dont the claws on canines show?

Usually,
But they may be trimmed down or just worn down. Still would have to be a darn big dog (or a goofy one).

bobcat maybe

god dang saint brnard dang