Keep up the good work, Knuckles. You're an inspiration to all! Related: Black Cat's Obsession with Fireplace Has People Having a Total Field Day If you have cats, you already know their activity ...

His owner told Newsweek that three-year-old Knuckles will "ask" to go on the treadmill at least six times per day.

We asked Dr Alexander Sliwa, leader of the Black-footed Cat Working Group and scientific consultant on the Big Cats series, why radio collars are a necessary tool for scientists to study wild cats.