In a scene eerily reminiscent of Rise of the Planet of the Apes, an escaped chimpanzee sought refuge on the power lines of a Japanese suburb. The chimp was eventually subdued after a frantic two-hour police chase, but you have to wonder: Why didnâ€™t he get zapped by the power lines? Hereâ€™s the answer.

The male chimp, named Chacha, escaped from Sendaiâ€™s Yagiyama Zoological park earlier in the day. At one point he climbed up an electricity pole, but was eventually caught after being shot with a tranquilizer gun.

Chacha seemed pretty chill on the power lines (even yawning at one point), but the dart threw him into a rage and he tried to attack his assailant. The chimp hung on as best he could until the sedative put him to sleep. He eventually fell onto a blanket held by workers on the ground but not before a sickening bounce off an adjacent building.

So how did Chacha the chimp not get electrocuted? Those wires carry about 1,000 volts of electricity, which is more than enough to ruin any primateâ€™s day. Physics Stack Exchange provides the answer:

The voltage difference is between the lines (e.g. in a 3-phase system) and between the line and ground. This voltage difference exists across the insulators and pole, as well as through the air to ground. These voltage differences are obviously small enough to avoid striking an arc, hence no current flows between the lines or between line and ground. If you are hanging from one line, there is no change in the separation between the lines (unless you are swinging wildly) and hence again no current flows between the lines. As the distance between the lines will usually be smaller than that between your feet and the ground, again no current will flow, and you will be safe. Note that, if this distance were too small, you would not be safe standing under the line either!

Thereâ€™s a bit of a catch:

Your real problem will be to get down from the line. Unless someone can switch off the power, you will need to touch both the line and the pole. If the pole is wood you should be OK, but a metal mast will kill you as you will then have a path for the current to flow (from the wire, through your body and the mast).

Or, you could just let yourself go and fall to the ground. Which is what happened to Chacha. Another possibility, of course, is that the wires were turned off, but we have no confirmation of that (but itâ€™s probably unlikely).