First off, it's a DC circuit you are completing by grabbing the terminals, not an AC one. AC circuits are dangerous due to the fact the cycles are a harmonic to your heart beat. Second, your body is not the best conductor in the world. Even though the amperage _rating_ is high on a regular car battery, the voltage (electrical potential) is low, and with the resistance, there's not much current going through you. You would get a million times more potent shock from static electricity.
you can get shock by batery . your brain just to numb to feel it . it a little tingle onley 12 volts more volts big the tingle . and abattery has lot of amps you can weld with a battery has enougf amps to do so