Dermacentor is a genus of ticks in the family Ixodidae, the hard ticks. The genus has a cosmopolitan distribution, with native species on all continents except Australia. Most occur in the Nearctic ecozone.Hosts of Dermacentor ticks include many large and small mammals, including horses, deer, cattle, lagomorphs, peccaries, porcupines, tapirs, desert bighorn sheep, and humans. The American dog tick (D.