Reason number 27 ticks are annoying: They prefer to bite you where you can't see them. A study published last winter in the journal Wilderness and Environmental Medicine found that 20 percent of tick bites occur in places–like the back, thigh, and groin–that are difficult to self-examine. The solution: Ask your spouse or, yes, hiking partner to check for you. "The window of opportunity to remove a tick is 36 hours," says Gary Wormser, an expert on preventing tick-borne diseases. Wormser says that most tick-transmitted parasites take that long to infect a host. If you do find a tick, he says, make sure to pull it out gently with tweezers, rather than burning, squeezing, or suffocating it with petroleum jelly.