Indiana here is a pug/dachshund mix, and at the time of recording, he was just a few months old. Not old enough to work out how mirrors work, that's for sure.
That said, many more experienced dogs still don't quite get the whole their-reflection-isn't-another-dog thing, so maybe we should give Indiana here a break.
What's more, dogs aren't the only animal to get foxed by shiny surfaces. As you'll discover from our video gallery below, guinea pigs, rabbits, mice and even tigers are easily confuzzled by the sight of their own mugs.
As for gorillas, well, they love checking themselves out. Take a look at this seriously clever 'gorilla cam' to see what we mean...