As rats have poor vision, they rely mostly on their other four senses - taste, smell, touch and hearing. They move through darkness by using their long whiskers and guard hairs on their bodies to guide them.
Rats are cautious feeders and if the food is in an exposed area and cannot be consumed quickly, they will drag it to a more hidden space.
They have an escellent sense of taste so traps must be baited with a food that is more attractive than what is normally available. Rats also use their keen sense of smell to locate food so the odor of any bait can be used to make it even more attractive to rats.
Long term rat eradication or pest control efforts must employ a variety of tactics from removing debris and food sources to "rat-proofing" the home to trapping or baiting with rodenticides. A list follows of Internet sources for commercial products for baiting, trapping and killing rats. They are presented in no particular order, endorsement or personal preference.
Rat Baits, Traps and Repellents:
1) Tomahawk - Live Rat and Mouse Traps
2) Woodstream - Electronic Rat Traps and Glue Boards
3) Harmony Farm Supply - Live Rat Traps
4) Peaceful Valley Farm - Live and Electronic Traps, Liquid Repellent
5) Gardener's Supply Company - Powdered Repellent
6) Havahart - Ultrasonic Rat Repellents, Snap Traps and Live Traps
7) Bell Laboratories - Read My Review
8) J.T. Eaton - Glue Boards, Glue Traps, Snap Traps, Rodenticides
For our lovely neighbors in Canada
Wilson Products - Rat Pellets, Baits and Blocks, Rodenticides
And those speaking the King's English: Great Britain
Pest Control Products - Rat Baits, Ultrasonic and Elctromagnetic Repellers and Rodenticides