Ticks are small, eight-legged arachnids that survive by feeding on the blood of other animals. As external parasites, they rely on hosts for nutrition and to progress through their life cycle. Ticks attach to a wide range of terrestrial vertebrates, including mammals, birds, and reptiles. Understanding the animals ticks live on is important for comprehending their ecology and potential impact on health.
Tick Life Stages and Their Hosts
Ticks undergo a four-stage life cycle: egg, larva, nymph, and adult. Each active stage, from larva to adult, requires a blood meal to survive and develop. A tick’s life cycle can range from two to three years.
Many tick species are “three-host ticks,” meaning they typically find a different host for each feeding stage. Larvae and nymphs often seek blood from smaller animals, while adults generally target larger hosts. For example, a blacklegged tick larva might feed on a mouse, then a nymph might feed on a bird, and finally, an adult tick could feed on a deer. Some species, like the brown dog tick, can complete all their active life stages on a single host.
Common Animal Hosts
Ticks feed on a diverse array of animals, from tiny rodents to large mammals, birds, and reptiles. Small mammals, such as mice, rats, and squirrels, are frequent hosts for larval and nymphal ticks due to their abundance and habitat overlap. White-footed mice are often significant hosts in this category.
Larger mammals also serve as common hosts for adult ticks. Deer are widely recognized carriers of ticks, especially blacklegged ticks, and can transport them across broad areas. Other large mammals like raccoons, opossums, coyotes, and foxes also host ticks. Domestic animals, including dogs, cats, and livestock such as cows, sheep, and horses, are susceptible hosts, particularly if they spend time outdoors.
Birds, including migratory species, can carry ticks over long distances, while ground-dwelling birds like turkeys and quail are more likely to host ticks due to their foraging habits. Reptiles and amphibians can also serve as hosts for certain tick species, with lizards known to carry ticks in some regions. Dense fur or feathers, high mobility, and social behaviors make these animals suitable for tick attachment and dispersal.
How Ticks Find Their Hosts
Ticks are unable to jump or fly, instead relying on a strategy called “questing” to find hosts. During questing, a tick climbs onto vegetation, such as blades of grass or leaves, and extends its front legs. It then waits patiently for a passing animal to brush against it, allowing the tick to quickly grasp onto the host.
Ticks possess specialized sensory abilities to detect potential hosts. They can sense carbon dioxide exhaled by animals, body heat, moisture, and vibrations from movement. Some species also detect host odors, such as lactic acid, which signals nearby muscle activity. Carbon dioxide is detectable up to 30 feet away.
The Role of Hosts in Disease Transmission
Animal hosts play a dual role in tick-borne diseases: providing blood meals for tick development and serving as sources or amplifiers of pathogens. Some animals act as “reservoir hosts,” harboring disease-causing pathogens without becoming ill and transmitting them to feeding ticks. White-footed mice and chipmunks are prominent reservoir hosts for certain tick-borne diseases, as ticks feeding on them are highly likely to become infected.
Other animals are considered “incidental hosts” because, while ticks may feed on them, they do not typically contribute to the pathogen’s life cycle or transmission. Humans fall into this category. Hosts also contribute to the spread of ticks and pathogens through natural movements, such as avian migration or the travel of large mammals.