now how do they do that?

Poppy caught skulking among guests at Victor

Recently our dog, or rather, Sarah's dog, had a brief everyday-miracle-type adventure. Poppy's a Jack Russell crossed with a miniature fox terrier, and stands at about twenty centimetres. She's about five years old, and has lived in this house of mine for most of her life. When Sarah moved out a few months ago she took Poppy with her. A couple of weeks ago Sarah's daughter moved into her small flat with Courtney, Sarah's four-year-old grand-daughter. It was a bit cramped, and Poppy didn't greatly appreciate some of Courtney's attentions. The other weekend, Sarah took herself off to a friend's house for a bit of respite, leaving Poppy at the mercy of Courtney and her mum. It was too much for her. She did a runner and arrived at my place after about an hour's journey.

To get to my place, Poppy had to pass through a few suburbs, from West Hindmarsh, on to Croydon, or Hindmarsh, depending on the route she took, then maybe to Ridleyton, Brompton, Renown Park and finally Devon Park. More importantly, though, she had to cross some of the busiest thoroughfares of the inner suburbs - South Road, Port Road, Grange Road and Torrens Road - as well as a railway line.

Poppy doesn't go out much. She doesn't like going for walks, and gets enough exercise - she's an energetic dog - running up and down hallways or in the back yard. We're talking about a very tiny dog.

She's had no formal training of any kind and doesn't know how to deal with traffic. I can't help but wonder how close she came to being roadkill.

Of course, the real mystery here is - how did she find her way to my house, via a route she'd never travelled before? How do dogs achieve this and what sense or senses do they use?

According to this site dogs have been estimated as having a sense of smell 100,000 times stronger than humans. I'm not even sure what that means, but does it mean that she was able to follow her nose to 'home' from several kilometres away, in a built up area alive with garden and house and factory and shop and car smells?

It's likely anyway that the olfactory was a factor. Not easy to find anything on the web about this, apart from lots of nasty dog jokes. However, I did find this story about a cat who travelled 1300 miles across Siberia to be re-united with its owner (presumably not via the Trans-Siberian Railway). So that puts the olfactory factor somewhat in doubt.

There's another vital sense, here vaguely called 'the sense of orientation', which perhaps incorporates the sense of smell. Though not a scientific website, this one suggests that wild animals were often migratory and depended on this 'sense of orientation', or 'instinct', over many generations to move them across miles and miles of unfamiliar territory. But what part of the brain is involved, how does the mechanism work?

May have to give up on this one.