I’ve spent some time thinking about ways to deal with rats. There are numerous approaches, from gassing to poisoning but still rats remain a problem for two main reasons: they eat huge amounts of food and they are also vectors for some pretty nasty diseases.
Any extermination device really needs to attract a rat, kill it and clear the trap for the next victim. All of this to be achieved at minimal expense, of course.
Today’s invention is a delayed-action trap based on the action of wild barley or foxtails. These grasses shed seeds which are barbed and work their way through the fur and skin of a huge range of mammals -eventually killing them if left untreated. I suggest creating a trap in the form of a narrow tunnel into which protrude the seed-barbs of living grasses. A rat squeezing through the box to reach some bait would embed many such barbs in its fur…eventually leading to its death.
The grasses would grow in a tray surrounding the tunnel and would naturally re-seed themselves several times a year. It might be possible to have separate trays for a number of species, with overlapping seeding seasons. A more advanced version would perhaps make use of grasses genetically engineered to have even more penetrative seed barbs.