Physical Characteristics

The western blacklegged tick, or Pacific tick, ranges in length from 1/16 inch for males to 3/8 inch for females engorged with a blood meal. Its body is oval-shaped and reddish brown in color,  and is not hard-shelled. Like its name, it has characteristic black legs. The first-instar larvae, or hatchlings, are 1/64 inch long and have six legs; second-instar larvae, or hatchlings after the first molt, are double that size, and have eight legs. 


Western Blacklegged Tick


The western blacklegged tick is the principal vector for Lyme disease in California. The adult of this species prefers medium-to-large mammals – people, dogs, cats, horses, cattle, deer and sheep. Adult females are most active in spring and in late summer. Like other ticks, this tick is a hitchhiker, programmed by genetics to climb to the top of a blade of grass, wave its free legs in the air and wait for a target mammal to brush by so that it can climb aboard – and suck some blood.


While out in the wild, tuck those pant legs into socks or boots, keep your shirts tucked in, stay buttoned up and use a tick repellent, and don’t sit on logs, stumps or the ground in the brush. Periodically examine your skin or clothes for ticks. If you find one, remove it with a slow, steady pull, so its mouthparts don’t stay embedded in your skin. Forceps or fingernails on – or just behind the mouthparts – should work, and be sure to wash the area of contact thoroughly afterward. You can put a drop of fingernail polish, Vaseline or isopropyl alcohol on the tick’s body anywhere from five to 30 minutes before you try to extricate its mouthparts from your body. Also, be very careful when clearing ticks from your dog, as infected secretions from ticks can transfer from your hands to your eyes or mucous membranes if you aren’t careful. Around the house, keep grass cut, trim back vegetation, and remove any plant or other debris, which provide harborage for rats and mice. Since ticks often hitch rides on rodents, a sanitation and exclusion approach targeted to reducing rodent activity should reduce the likelihood of ticks, too. Your Clark technician should be a good source for advice, and can prescribe treatments to reduce rodent activity around your home.

Latin name: Ixodes pacificus