Regional tick guide

Ticks in California

Explore reviewed tick occurrence records for California, with links to identification profiles, evidence and practical guidance.

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Tick guide for California

About ticks in California
California supports several medically relevant hard ticks across coastal, foothill, forest and grassland habitats. California public-health guidance highlights the western blacklegged tick, Pacific Coast tick and American dog tick among important species encountered in the state.

When are ticks active?
Tick exposure can occur throughout the year. Western blacklegged tick adults are most active in fall and winter, with nymphs most active in spring. Pacific Coast and American dog tick activity is generally greatest from early spring to mid-summer.

Health and identification
Use the linked species profiles for identification guidance. Tick presence does not establish pathogen infection or transmission, and risks vary substantially by place, season and species.

Reviewed sources

No verified location-specific species records yet

We have not yet connected a reviewed species occurrence record specifically for California. The species below are provided as general identification resources and must not be treated as confirmed records for this location.

Common ticks in the USA

Adult female Amblyomma americanum lone star tick showing the central pale spot

Lone star tick

Amblyomma americanum

Amblyomma hard_tick United StatesColorado
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An aggressive human-biting hard tick widely distributed in the eastern United States and especially common in the South. Larvae, nymphs and adults bite people.

Identification:

The adult female has a single pale or white spot near the centre of the scutum. Adult males have pale markings around the posterior margin rather than one central spot. Mouthparts are relatively long.

Hosts: Humans, White-tailed deer, Small mammals, Birds, Dogs

Habitats: Woodland, Woodland edges and trails, Grassland and shrubland

Photographs and visible features may be insufficient for definitive identification.

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Adult male and female Dermacentor variabilis American dog ticks on a blade of grass

American dog tick

Also known as: Wood tick

Dermacentor variabilis

Dermacentor hard_tick United StatesColorado
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A widespread North American hard tick. Adults commonly bite dogs and humans, while larvae and nymphs feed mainly on small mammals.

Also known as: Wood tick

Identification:

Adults have short mouthparts, eyes and festoons, with pale ornamentation on the dorsal shield. Females have a pale patterned scutum at the front; males have ornamentation across most of the dorsum.

Hosts: Humans, Dogs, Small mammals, Large mammals

Habitats: Woodland edges and trails, Grassland and shrubland

Photographs and visible features may be insufficient for definitive identification.

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Engorged adult female Ixodes scapularis blacklegged tick viewed from the side

Blacklegged tick

Also known as: Deer tick, Bear tick

Ixodes scapularis

Ixodes hard_tick United StatesConnecticut
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A widespread eastern United States hard tick and major human-biting vector. Nymphs and adult females are most often reported on people, although larvae also bite humans.

Also known as: Deer tick, Bear tick

Identification:

Adult females typically have a dark scutum and legs contrasting with an orange-red posterior body when unfed. Adult males appear more uniformly dark because the scutum covers most of the dorsum. Ixodes ticks lack eyes and festoons and have the anal groove anterior to the anus.

Hosts: Humans, White-tailed deer, Small mammals, Birds, Lizards

Habitats: Woodland, Woodland edges and trails

Photographs and visible features may be insufficient for definitive identification.

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Adult female and male Rhipicephalus sanguineus brown dog ticks in dorsal view

Brown dog tick

Rhipicephalus sanguineus

EuropeTexas
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A globally distributed, dog-associated hard tick able to complete its life cycle in buildings and kennels. UK records are linked to importation; UKHSA reports no current evidence of establishment outdoors or as a resident UK population.

Identification:

Laterally produced angular basis capituli.

Eyes and festoons present.

Scutum lacks ornamentation.

Mouthparts relatively short compared with the basis capituli.

Coxa I has large paired internal and external spurs.

Rhipicephalus sanguineus is a species complex in some literature; expert morphological and sometimes molecular review may be necessary.

Photographs and visible features may be insufficient for definitive identification.

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Practical tick guidance

Related guidance

Use these VuxLore® resources alongside the location records and species profiles above.

Identify ticksSpecies, life stages and identification guidance Prevent and checkReduce exposure and perform thorough tick checks Remove ticksRemoval methods, tools and common problems Bites, symptoms and healthSourced guidance about bites, symptoms and disease

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