Historically the rat has been labeled a pest and more-than-a-nuisance due to their capacity to carry diseases that can infect humans, and their propensity to reproduce like... well... uh... rodents. However, in this wonderfully modern time in which we live the rat is being put to task by their human overlords doing much more productive things.
One promising rat-platform is the Pouched Rat, a nocturnal native of Africa. Because they forage for food at night, they are endowed inordinate acumen in their sense of smell. Though these rats are often considered a menu item in their native sub-Saharan Africa, a fellow by the name of Bart Weetjens thought that he could find a better use for the creatures. Africa's lands have been host to a collage of armed conflicts, leaving the landscape strewn with landmines. The rats' propensity for speedy reproduction makes them plentiful enough to dare risk them in the hazardous job of sniffing out such hazards. Fortunately, these foodstuffs are apt to be trained.
Of course, there are concerns about the mine-sweeping rats. Some critics decry that animals cannot be as accurate as man-made alternatives such as a metal detector or mine-sweeping robots. The retort is that the rats are not distracted by the metal flotsam as metal detectors are, and that these poverty-stricken areas haven't the means to acquire robots. According to a report in the Washington Post, there are some people who see a mine-sweeping robot limping over a field, burning and smoldering after successfully locating several bombs, and order the test stopped because it's inhumane to the robot.
Rats' slick, agile frames are also well suited to complex searching, but usually such tasks defy their small brains. To remedy this shortcoming, researchers have tried sticking a bunch of electrodes directly into the rats' brains to enhance their skill set.
Though the rat-tasks currently being pursued may not prove to be practical, there may be some future benefit to knowing how to bend the prolific vermin to our will. It might be that in the future the rat will become a contributing member of our society; perhaps consigned to menial labor like removing litter, or following cables. Or maybe bionically enhanced rodents will become our new overlords... until the wrath of Alberta falls upon them.