Ticks are ectoparasites (external parasites), living by hematophagy on the blood of mammals, birds, and occasionally reptiles and amphibians. Ticks are important vectors of a number of diseases, including Lyme disease.

The life cycle of the hard tick requires one to three years to complete, and may require one, two or three different host animals. The following describes the three-host lifecycle

1. An adult female tick drops off her final host, lays her eggs and dies.

2. Tiny six-legged larvae congregate on grasses or other leaves and stems not far from ground level. Lucky individuals complete that stage after attaching to a host, feeding, and dropping off. The larval stage can cause intense itching on humans, but does not transmit disease.

3. Larvae molt and emerge as the nymph stage, about 1.5 mm long and again climb a grass stem to await a host. The nymph stage also causes intense itching in humans.

4. Engorged nymphs drop off, molt to the adult stage, approximately 3 mm long, mate, and again climb a stem to await a host. Adults are amazingly stealthy on humans in spite of their size, and may not be noticed until they have been attached for a considerable time.

Ticks reproduce sexually, use internal fertilization and are oviparous. Ticks produce a lot of young but the young are not nurtured.