[3] Within the Parasitiformes, ticks are most closely related to the Holothyrida, a small group of free living scavengers with 32 described species confined to the landmasses that formed the supercontinent Gondwana.

[16] The phylogeny of the Ixodida within the Acari is shown in the cladogram, based on a 2014 maximum parsimony study of amino acid sequences of 12 mitochondrial proteins.

[19] The gnathosoma is a feeding structure with mouthparts adapted for piercing skin and sucking blood; it is the front of the head and contains neither the brain nor the eyes.

[22] In addition to being used for locomotion, the tarsus of leg I contains a unique sensory structure, Haller's organ, which can detect odors and chemicals emanating from the host, as well as sensing changes in temperature and air currents.

[16] The hard protective scutellum, a characteristic of this family, covers nearly the whole dorsal surface in males, but is restricted to a small, shield-like structure behind the capitulum in females and nymphs.

A centrally positioned dorsal plate with ridges projecting slightly above the surrounding surface, but with no decoration are often present.

The eyes are on the sides of the body, the spiracles open between legs 3 and 4, and males and females only differ in the structure of the genital pore.

[36] Nuttalliellidae can be distinguished from both ixodid and argasid ticks by a combination of a projecting gnathosoma and a soft leathery skin.

Other distinguishing characteristics include the position of the stigmata, the lack of setae, the strongly corrugated integument, and the form of the fenestrated plates.

[6][40] This behavior evolved independently within the separate tick families as well, with differing host-tick interactions driving the evolutionary change.

Both groups of soft tick feed rapidly, typically biting painfully and drinking their fill within minutes.

The proteins with anti-inflammatory properties, called evasins, allow ticks to feed for eight to ten days without being perceived by the host animal.

Researchers are studying these evasins with the goal of developing drugs to neutralise the chemokines that cause myocarditis, heart attack, and stroke.

[46] Ticks do not use any other food source than vertebrate blood and therefore ingest high levels of protein, iron and salt, but few carbohydrates, lipids or vitamins.

[47] Ticks’ genomes have evolved large repertoires of genes related to this nutritional challenge, but they themselves cannot synthesize the essential vitamins that are lacking in blood meal.

[50][51][52] Although Coxiella and Francisella endosymbionts are distantly related bacteria, they have converged towards an analogous B vitamin-based nutritional mutualism with ticks.

[47] Their experimental elimination typically results in decreased tick survival, molting, fecundity and egg viability, as well as in physical abnormalities, which all are fully restored with an oral supplement of B vitamins.

[58] They tend to flourish more in warm, humid climates, because they require a certain amount of moisture in the air to undergo metamorphosis, and low temperatures inhibit their development of eggs to larvae.

[61][62] Tick parasitism is widely distributed among host taxa, including marsupial and placental mammals, birds, reptiles (snakes, iguanas, and lizards), and amphibians.

[68] Ticks like shady, moist leaf litter with an overstory of trees or shrubs and, in the spring, they deposit their eggs into such places allowing larvae to emerge in the fall and crawl into low-lying vegetation.

According to these studies, certain features of a given microclimate – such as sandy soil, hardwood trees, rivers, and the presence of deer – were determined to be good predictors of dense tick populations.

With increasing participation in outdoor activities such as wilderness hikes, more people and their dogs may find themselves exposed to ticks.

Once engorged, they drop off the host and find a safe area in the natural environment in which to molt into adults, this typically occurs during the winter.

The following spring the adult ticks emerge and seek out a larger host, often a large mammal such as cattle or even humans.

Ticks can be disposed of by flushing them down the toilet, placing them in a container of soapy water or alcohol, or sticking them to tape that can then be folded over and thrown away.

[21][84] Bifenthrin and permethrin, both pyrethroids, are sometimes used as tick-control measures, although they have the disadvantage of being carcinogenic and able to attack the nervous systems of other species besides ticks.

This includes five levels of containment, viz., storage vials within humidified desiccators, within environmental chambers, within a tick suite, within a BSL4 laboratory.

[93] With the possible exception of widespread DDT use in the Soviet Union, attempts to limit the population or distribution of disease-causing ticks have been quite unsuccessful.

[97] This supports the results of a study from the northeastern United States, in which the incidence of Lyme borreliosis was negatively correlated with the density of red fox, possibly because foxes decrease the density of white-footed mice (Peromyscus leucopus), the most important reservoir-competent host for Borrelia burgdorferi.

The synthetic pyrethroid insecticide phenothrin in combination with the hormone analogue methoprene was a popular topical flea and tick therapy for felines.