Yes, you can train your pet rat. And why shouldn't you? You feed it. You care for it. You shelter it from bears, birds and hunters that are just really bored. The good news is that rats are actually smart enough to dig what you're trying to sell them, and the better news is that we're about to explore some ways you and your rat can get on the same page.
Take It Slow
Don't try training your pet rat right away. Give it time to get used to its new home and surroundings. A good analogy to use is that of college orientation; you can't be expected to put forth your best focus and concentration until you're comfortable in your environment, so why should rats be any different? After you and your rat are comfortable with one another, stay seated on the floor while you first handle it. He or she will feel more confident in a stationary position, and won't suffer any harm in the event of a fall or mishap.
Using the Litter
You want to keep your rat's cage/aquarium as sanitary as possible, and a great way to do that (while also getting some training under your belt) is to teach it to use its litter tray. This can be achieved by going into the rat's quarters on cleaning day (when the rat's out of the cage, most likely) and removing all of its…leftovers. Next, insert the litter tray, and put said droppings inside of it, in the same spot where the rat was doing most of its business. Every time the rat takes care of things in its new, designated area, reward it with a treat, or with a vocal cue praising him/her for his/her hard work.
Ridin' the Shoulder
The most basic trick. Tempt the rat up your sleeve to your shoulder by placing a treat where you want him to sit. If he doesn't climb up on his own, PetPlace.com suggest setting your pet on your shoulder for short intervals of time until it gets used to being up there. Praise it or reward it with a treat for sitting quietly, and take it off your shoulder as soon as it starts to get antsy. Over time, it should grow comfortable being in this position, and will eventually allow you to walk from place to place, a passenger of your motion.
You can also train your rat to fetch. This can be accomplished in a way similar to that in which you train a dog to fetch; throw the to-be-fetched object, and reward the rat with a treat every time it takes a step back to you with the thrown object.
Domesticated animals may not always respond to specific words in the way dogs and cats do, but they will recognize certain sounds. So if you want to cue your rat in on the fact it's eatin' time, don't hesitate to apply the Pavlovian bell theory to your teachings.
Most people are scared of bats, but some desire to have them as pets. It is essential to learn about these creatures before you begin to care for one.