In a recent chapter of my fantasy novel that I put up for critique on Critique Circle, the antagonist has trained a rat to sniff the trail of the protagonist, with the aim of going after him to kill him. One of my critiquers asked the question – Is it plausible that a rat could sniff out and follow a scent that’s three or four days old? For me it was one of those ‘Darn it’ moments. I knew rats had a good sense of smell and just presumed that they’d be able to do it, but I didn’t know.
Anyway, I spent an hour this afternoon doing some research and I did find out some very interesting things about rats. Did you know, for instance, that rats are now used to sniff out land mines? Apparently, they’re much better at it than dogs because 1. they don’t get attached to their trainer, so anyone can use them and 2. they’re not so heavy, so they’re less likely to set off a mine inadvertently. The only downside is that they can’t be transported from place to place because of the risk of disease (… well, they are rats, after all), and they don’t live as long as dogs.
Something else I didn’t know is that they can detect whether someone has tuberculosis just by sniffing them. Also, when they smell something on the breeze, they can tell which way the smell is coming from, no matter what other smells are blowing around, because their nose has scent receptors on either side.
They’re also being trained to search through buildings that have been demolished by earthquakes, to sniff out survivors. They have radio transmitters implanted in their brains so that their ‘ah ha, found one’ moment can be recorded and plotted (I don’t suppose they can call out or even bark, can they?). They can fit into places that no one else could and have the sense to back out if it’s too dangerous.
Who’d have thought there could be so much to know about rats? That’s what I love about writing – there’s always so much interesting stuff to find out in the course of getting it right. I just have to watch I don’t get side-tracked.
Only one problem – I still don’t know the answer to the question. How old a scent can a rat follow? Any rat experts out there?