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Tick Identification: How to Tell U.S. Tick Species Apart

Identify a tick by its mouthparts, its scutum (the shield behind the head), its color pattern, and the region you are in. Only a select few species bite people and spread pathogens. In the U.S., blacklegged, lone star, and American dog ticks account for the large majority of ticks recorded on people.

What do you actually look at to identify a tick?

The Virginia Department of Health puts it plainly: ticks can be identified by looking at certain characters, like the shape of their mouthparts and their scutum, along with colors and patterning. A review in Clinical Microbiology Reviews gives the genus-level characters for hard ticks: mouthpart length relative to the basis capituli, eyes present or absent, festoons present or absent, and markings on the dorsal shield. The same review describes Ixodes ticks by their elongated mouthparts, absence of eyes and festoons, and plain unmarked dorsal shield. Dermacentor ticks have relatively short mouthparts, eyes and festoons, and an ornate patterned shield. Amblyomma ticks have eyes, festoons, an ornate shield, and palps longer than the basis capituli.

Mouthparts settle the most common mix-up. Virginia's health department distinguishes the American dog tick by its short, rounded mouthparts and the similar-looking Gulf Coast tick by its long, rectangular ones. On an adult female blacklegged tick the scutum is black and the body behind it is red-brown; Minnesota's health department calls that coloring reddish-orange. Adult males are dark brown or black and resemble a small watermelon seed. Size helps, but only in comparison: blacklegged ticks are much smaller than American dog ticks, and lone star ticks sit in between.

Which ticks bite people in the United States?

A 2022 review in Ticks and Tick-borne Diseases compiled published records of ticks collected while biting humans or crawling on skin or clothing in the U.S.: 36 hard tick species (234,722 specimens) and 13 soft tick species (230 specimens). The top five hard ticks recorded from humans were the blacklegged tick (158,008 specimens), the lone star tick (36,004), the American dog tick (26,624), the western blacklegged tick (4,158), and the Rocky Mountain wood tick (3,518). The brown dog tick (714) and Gulf Coast tick (335) also cleared 250 records.

Blacklegged tick (Ixodes scapularis)

Widely distributed across the eastern United States. Adult female: black scutum, red-brown body behind it. Transmits Borrelia burgdorferi and B. mayonii (Lyme disease), Anaplasma phagocytophilum (anaplasmosis), Babesia microti (babesiosis), B. miyamotoi, Ehrlichia muris eauclairensis (ehrlichiosis), and Powassan virus. The CDC says the greatest risk of being bitten is in spring, summer, and fall, though adults may be searching for a host any time winter temperatures are above freezing. All life stages bite humans, but nymphs and adult females are most commonly found on people.

Western blacklegged tick (Ixodes pacificus)

Found along the Pacific coast, particularly northern California. Larvae and nymphs often feed on lizards, birds, and rodents; adults more commonly feed on deer. Transmits Anaplasma phagocytophilum, Borrelia burgdorferi, and very likely B. miyamotoi. Nymphs and adult females are more often reported on people, but larvae also bite people.

Lone star tick (Amblyomma americanum)

Widely distributed in the Northeast, South, and Midwest, and more common in the South. The adult female carries a single white dot, the "lone star," which Virginia's health department places at the center of her back. The CDC calls the species a very aggressive tick that bites humans, and says nymphs and adult females most frequently bite people and spread disease. It transmits Bourbon virus, Ehrlichia chaffeensis and E. ewingii (ehrlichiosis), Heartland virus, and tularemia. A circular rash of unknown cause (STARI) sometimes follows its bite, and growing evidence suggests alpha-gal syndrome, a red meat allergy, may be triggered by lone star tick bites. Its saliva can be irritating, so redness at a bite site does not necessarily mean infection.

American dog tick (Dermacentor variabilis, D. similis)

D. variabilis is widely distributed east of the Rocky Mountains and occurs in limited areas west of them. The newly described D. similis, recognized as a separate species in 2021, is found west of the Rockies, and more research is needed to understand the role of these species in disease transmission. Short, rounded mouthparts, ornate shield. Transmits tularemia and Rocky Mountain spotted fever. Highest bite risk is spring and summer, and adult females are most likely to bite people. Virginia's chart notes that only the adult stage is known to bite humans; nationally, adults were 99.6 percent of specimens recorded from people.

Rocky Mountain wood tick (Dermacentor andersoni)

Rocky Mountain states and southwestern Canada, at elevations from 4,000 to 10,500 feet. Adults feed primarily on large mammals; larvae and nymphs feed on small rodents. Transmits Rocky Mountain spotted fever, Colorado tick fever, and tularemia. Adults were 99.6 percent of specimens recorded from people, and adult and nymphal ticks are primarily associated with pathogen transmission to humans.

Gulf Coast tick (Amblyomma maculatum)

Primarily southeastern U.S., with focal populations in the Northeast, Midwest, and Southwest. Long, rectangular mouthparts separate it from the American dog tick. Larvae and nymphs feed on birds and small rodents, while adults feed on deer and other wildlife. Transmits Rickettsia parkeri rickettsiosis, a form of spotted fever, and adults are the stage associated with that transmission; adults were 94 percent of the specimens recorded from people.

Brown dog tick (Rhipicephalus sanguineus)

Found worldwide, and the one tick here that occurs in Hawaii. Dogs are its primary host at every life stage, and it prefers to feed on the same host throughout, but it will bite humans and other mammals. It is the primary vector for Rocky Mountain spotted fever in the southwestern U.S. and along the U.S.-Mexico border. Michigan's health department notes it can uniquely survive and breed in indoor environments and has been associated with kennel, shelter, and breeding facilities.

Two more worth knowing

The Asian longhorned tick (Haemaphysalis longicornis) was reported in the United States for the first time in 2017. Compared with well-known native ticks, the CDC says it appears less attracted to humans. Its identifying trait is behavioral: females can lay eggs and reproduce without mating, so thousands may turn up at once in grass or shrubs or on an animal.

Soft ticks (Ornithodoros) transmit soft tick relapsing fever, usually in mountainous areas of western states and parts of Texas, most often when people stay overnight in rodent-infested cabins. You will probably never notice one. The CDC says bites from soft ticks are brief, usually lasting less than half an hour, and painless, and that most people are unaware they have been bitten.

How do you tell a larva, nymph, and adult apart?

Count the legs first. Most ticks go through four life stages: egg, six-legged larva, eight-legged nymph, and adult. Then judge size: the CDC puts adult blacklegged ticks at approximately the size of a sesame seed and nymphs at approximately the size of a poppy seed.

The CDC notes that nymphal ticks pose a particularly high risk because of their abundance and small size, which makes them difficult to see, while adult females are more likely to be noticed and removed before transmission. In areas of the eastern United States where Lyme disease cases are common, nymphs are actively questing from April through July, and adults are most active in early spring and fall.

How do you narrow it down by where you live?

Geography rules species out fast. The CDC notes that naturally occurring populations of the tick species it maps do not occur in Alaska, though the brown dog tick occurs in Hawaii. One further caution from the CDC: even though a species is found in a region, that does not necessarily mean it transmits a specific disease there. Blacklegged ticks in most areas of the southeastern United States are almost never infected with Lyme disease bacteria. In Minnesota, by contrast, the state health department reports that on average about 1 in 3 adult blacklegged ticks and 1 in 5 nymphs carries it.

Does knowing the species change what you should do?

Species changes what you watch for afterward, but the first step is the same either way: remove the tick right away. The CDC says to grasp it as close to the skin's surface as possible with clean fine-tipped tweezers and pull away with steady, even pressure, without twisting or jerking. Do not use petroleum jelly, heat, or nail polish to make it detach.

Species knowledge matters at the doctor's office. As Virginia's health department puts it, if you start to become sick after a tick bite, knowing what type of tick it was may help you and your healthcare team discuss testing and treatment options. If you develop a rash or fever within several days to weeks after removing a tick, see your doctor.

How do you keep ticks off in the first place?

Tick exposure can occur year-round, but the CDC notes ticks are most active during warmer months, April through September. The CDC recommends treating clothing and gear with products containing 0.5% permethrin, and using EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol, or 2-undecanone, looking for an EPA registration number on the label.

Back indoors, the CDC says to check under the arms, in and around the ears, behind the knees, in your hair, and around the waist. Showering within two hours of coming indoors has been shown to reduce Lyme disease risk.

Longsleeve is an EPA-registered picaridin lotion (EPA Reg. No. 101457-1). It repels mosquitoes and ticks for up to 14 hours. It is fragrance-free, with nine disclosed ingredients.

Tick identification FAQ

Should I send the tick off to be tested?

The CDC says commercial tick testing is in general not recommended, and that results of tick testing should not be used for treatment decisions. Knowing the species is still useful: Virginia's health department notes it may help you and your healthcare team discuss options if you become sick.

Which tick has a white spot on its back?

The adult female lone star tick. The CDC says she is distinguished by a white dot or "lone star" on her back, which Virginia's health department places at the center of her back.

How long does a tick have to be attached to transmit Lyme disease?

The CDC states that in general, infected ticks must be attached for more than 24 hours to transmit infection, and that prompt removal can prevent transmission.

Can any tick give me Lyme disease?

The CDC says Lyme disease bacteria causing human infection in the United States are spread to people by blacklegged (Ixodes) ticks: the blacklegged tick in the northeastern, mid-Atlantic, and north-central states, and the western blacklegged tick along the Pacific Coast. Other species carry other pathogens, which is why exposure history is worth reporting to a clinician.

Sources

  1. CDC, Where Ticks Live. https://www.cdc.gov/ticks/about/where-ticks-live.html
  2. CDC, Tick Lifecycles. https://www.cdc.gov/ticks/about/tick-lifecycles.html
  3. CDC, Blacklegged Tick Surveillance. https://www.cdc.gov/ticks/data-research/facts-stats/blacklegged-tick-surveillance.html
  4. CDC, Western Blacklegged Tick Surveillance. https://www.cdc.gov/ticks/data-research/facts-stats/western-blacklegged-tick-surveillance.html
  5. CDC, American Dog Tick Surveillance. https://www.cdc.gov/ticks/data-research/facts-stats/american-dog-tick-surveillance.html
  6. CDC, Lone Star Tick Surveillance. https://www.cdc.gov/ticks/data-research/facts-stats/lone-star-tick-surveillance.html
  7. CDC, How Lyme Disease Spreads. https://www.cdc.gov/lyme/causes/index.html
  8. CDC, What to Do After a Tick Bite. https://www.cdc.gov/ticks/after-a-tick-bite/index.html
  9. CDC, Preventing Tick Bites. https://www.cdc.gov/ticks/prevention/index.html
  10. CDC, About Soft Tick Relapsing Fever (STRF). https://www.cdc.gov/relapsing-fever/about/about-strf.html
  11. CDC, Tickborne Diseases of the United States: A Reference Manual for Healthcare Providers (PDF). https://www.cdc.gov/ticks/media/pdfs/2025/03/tickborne-diseases-manual-508.pdf
  12. Eisen L. Tick species infesting humans in the United States. Ticks and Tick-borne Diseases, 13(6), 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC10862467/
  13. Mathison BA, Pritt BS. Laboratory Identification of Arthropod Ectoparasites. Clinical Microbiology Reviews, 27(1):48-67, 2014. https://pmc.ncbi.nlm.nih.gov/articles/PMC3910909/
  14. Virginia Department of Health, Tick Identification. https://www.vdh.virginia.gov/ticks/tick-identification/
  15. Virginia Department of Health, Tick Identification Chart (PDF). https://www.vdh.virginia.gov/content/uploads/sites/6/2024/04/Digital-Tick-Identification-Chart.pdf
  16. Minnesota Department of Health, Ticks. https://www.health.state.mn.us/diseases/tickborne/ticks.html
  17. Michigan Department of Health and Human Services, Michigan's Five Most Common Ticks (PDF). https://www.michigan.gov/-/media/Project/Websites/emergingdiseases/Folder2/5commonticks.pdf

Last reviewed 2026-08-05 · every claim on this page is sourced above