American Dog Tick
Dermacentor variabilis · Arachnid, Invertebrate, Cold-blooded, Wild
Animal Family
Family Ixodidae, order Ixodida, class Arachnida
Animal Category
Insect/Arthropod
Breed / Variety
Dermacentor variabilis
Conservation Status
Not evaluated by the IUCN, but considered common and widespread with a stable population trend.
About This Creature
Small, oval-shaped arachnid with a flattened body. Unfed adults are about 3 to 5 mm long, while engorged females can swell significantly up to 15 mm. Features distinct ornamentation with white or silver markings on a dark brown shield (scutum).
Physical Characteristics
Eight legs as adults, no antennae, fused cephalothorax and abdomen, specialized mouthparts (hypostome) for piercing skin and drawing blood, ornamented dorsal shield.
Behavior & Temperament
Questing behavior to find hosts, active primarily in spring and summer, non-social, relies on vibration, heat, and carbon dioxide to detect passing hosts.
Habitat & Diet
Origin Region
North America, widely distributed east of the Rocky Mountains and in parts of the Pacific Coast
Habitat
Grasslands, shrublands, open woods, and areas along trails and roadsides; terrestrial
Diet & Nutrition
Obligate hematophage (feeds exclusively on blood of mammals, primarily medium-to-large hosts like dogs, humans, and deer) across its three-larval, nymphal, and adult life stages.
Lifespan & Health
Lifespan ranges from several months up to 2 years depending on host availability and environmental conditions; acts as a vector for pathogens such as Rocky Mountain spotted fever and tularemia.
Special Characteristics
Capable of surviving long periods without food, injects an anticoagulant and anesthetic saliva while feeding, major vector of zoonotic diseases.
Ecological Information
Serves as a parasite within terrestrial food webs, preying upon mammals and acting as a vector for various pathogens, potentially regulating host populations or impacting wildlife health.