The Homing Instinct in Animals

There are stories of animals inexplicably finding their way home after journeys of hundreds of miles, such as this one:
http://science.time.com/2013/02/11/the-m...ating-cat/

I think in its way this story of a pet travelling five miles from its new home to its old home - courtesy of the Daily Grail - is equally remarkable, because the pet was a tortoise:
https://sacramento.cbslocal.com/2019/10/...iles-away/

My brother and his wife adopted a very young ginger kitten that turned up on their doorstep and wouldn't go away... they had it for a couple of weeks... then had all the vets stuff done, and put a collar on it with a name tag and telephone number... their two existing cats didn't get on with it though...

About two months later it went missing... then they got a phone call from the cats original owners to say their cat had returned to them... they lived about 25 mile away... in the vicinity of where my brothers wife worked and parked her car... so we think there is a high probability it climbed into the engine compartment of her car the first time... and possibly climbed into the engine compartment again to get back home... but there is is not really any way of knowing.