Ticks are blood-feeding external parasites of mammals, birds, and reptiles throughout the world.
Hard ticks have three distinct life stages.
The larva which emerges from the egg has six legs. After obtaining a blood meal from a vertebrate host, it molts to the nymphal stage and acquire eight legs. The nymph feeds and molts to the next and final stage - the adult, which also has eight legs. After feeding once more, the adult female hard tick lays one batch of thousands eggs then dies. The time to completion of the entire life cycle may vary from less than a year in tropical regions to over three years in cold climates where certain stages may enter diapause until hosts are again available.