Cold-blooded and obsessed with efficiency, Ratbat's primary concern is looking out for himself. He treats his responsibilities, whether as a fuel auditor or as leader of Decepticons, as a business. In his book, everything comes down to profit and loss.
In his role as fuel scout, Ratbat carries sensors that allow him to detect and evaluate the quality of fuels of various types, from primitive hydrocarbons to Energon. He can process any number of these different fuels to power himself.
Although obsessed with efficiency, like any good CEO, Ratbat allows himself a small indulgence: He enjoys sinking his fangs into the fuel tanks of Terran automobiles, the more expensive the better. He enjoys nothing more than savoring high-test gasoline siphoned from a hapless yuppie's Mercedes or BMW.
His alt-mode is a Bat/Microcassette.