While you're playing outdoors in Yosemite National Park, there are a few bugs and other critters to watch out for.
Mosquitoes are the most common annoyance, especially next to streams, rivers and lakes. Bring plenty of insect repellant with you. As snow melts in the high country, mosquitoes may start to swarm, so think twice before planning an alpine lake hike or backpacking trip during July.
Ticks are common in the lower-elevation forests of the western Sierra Nevada foothills, although you may encounter them elsewhere in the park, too. Ticks bites can become infected and cause serious illnesses, notably Lyme Disease. Take precautions against ticks by using insect repellant with DEET, wearing light-colored clothing and tucking your pants into your socks. Perform a tick check on your partner after hiking through grasslands, underbrush or thickly forested areas.
Spiders and snakes are the most common stinging creatures you'll encounter in the park. Among the former are black widows, brown recluses, and even tarantulas; the latter primarily include rattlesnakes. Most people bitten by snakes in Yosemite either accidentally stepped on it or intentionally provoked it (e.g., badgering the animal with a stick). For snake bites, do not attempt to suck the venom out or to apply a tourniquet. Seek medical help as soon as possible.