SFU researchers develop fiendish mouse, rat trap
Using bevy of scents shows dramatically increased capture rates compared to classic designs
Researchers at Simon Fraser University have devised a fiendishly clever way to trick rats into getting inside a trap by exploiting their snacking preferences, the comfort of community, the promise of sexy fun time and even the cries of baby rodents to play on a mother’s instincts.
Animal communication expert Gerhard Gries started by creating a food odorant that mimics a smorgasbord of cheese, hazelnuts, chocolate, fresh meat and other rat favourites.
That was effective — certainly better than commercially available attractants — but rats are naturally wary of new objects and even the promise of a tasty meal isn’t always enough to lure them in.
So Gries added pheromones and steroids, such as male testosterone or female progesterone and estradiol to let the rats know that, A) there is another rat inside, so it’s not that dangerous and, B) maybe you’ll get lucky if you go inside. The female blend increased captures of male mice eight-fold and male rats 13-fold, while synthetic testosterone increased captures of adult female mice 15-fold.
“We were pleasantly surprised, it’s an amazing increase in bait attractiveness,” said Gries, who is developing systems effective on Norway rats and house mice. Those results were published in the journal ChemBioChem.
But Gries wasn’t quite done. To really seal the deal for the most wary rodents, his team recorded the ultrasonic squeaks of baby rodents and played them back inside the trap. The recording quadrupled the catch rate over even the combined food and pheromone baits.
“We think the female rats are going in to check on the babies and for the male rats, if they aren’t his babies, he would eat them like a juicy steak,” he said.
The lab’s results have attracted attention from pest-control firms all over the world and the technology promises to be extremely affordable. Pheromone-based insect traps can be bought for less than $10.
Gries is determined to replace poisoning as a means of pest control to reduce the risk that poison-filled rodents will lead to secondary poisonings of predators such as coyotes, foxes and birds.
Local rats are most likely to carry leptospira, a bacterium carried in rat urine that causes fever in humans, though the bubonic plague has recently spread across Madagascar, according to Kaylee Byers, a PhD student at the University of B.C. doing research at The Vancouver Rat Project.
Rats are a foreign, invasive species from Asia, but they thrive in Vancouver.
“Anecdotally, it seems as though we’ve had a rise in our rat population over the past few years ... pest-control professionals say they are getting more calls,” she said. “But really, we have no idea.”
Researchers at SFU, including Gerhard Gries, have developed a phenomenally effective attractant for rats and mice.