Fauna
Arachnid

Western Black-legged Tick

Ixodes pacificus

Also known as Western Blacklegged Tick

Western black-legged ticks wait patiently on the tips of grasses and low shrubs, extending their front legs to grasp passing hosts in a behavior known as questing. These hardy parasites require three distinct hosts to complete their multi-year life cycle, transitioning from tiny larvae to nymphs and finally to breeding adults. On the Pacific coast, their relationship with local lizards plays a fascinating role in reducing the local prevalence of Lyme disease.

ParasiticWoodlandForest-Dwelling
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & preyMule Deer, Western Fence Lizard, Deer Mice
Predators
  • Opossums
  • Wild Turkeys
  • Nematodes
ThreatsHabitat clearing, host population declines, and extreme drought
HabitatsDense woodlands, chaparral, brushy areas, and tall grasslands
Life spanApproximately 3 years
  1. FamilyIxodidae
  2. SpeciesIxodes pacificus
Range data is not available yet.
Interaction riskModerate
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is moderate
Can transmit Lyme disease; wear long pants and perform thorough tick checks after hiking.
Why it is dangerous
Transmits Lyme disease and other pathogens through its bite.
How to recognize a risky encounter
Adult females have a reddish-orange abdomen with a dark scutum, while males are entirely dark brown.
What to do
Avoid contact by staying on cleared trails, and use EPA-approved insect repellents containing DEET or picaridin.
Responsible observation
  • Prevention: Wear light-colored clothing and tuck pants into socks when walking through tall grass.
  • Removal: Use fine-tipped tweezers to grasp the tick close to the skin and pull straight upward.
  • Inspection: Perform a thorough body check and wash clothes in hot water after outdoor activities.
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