It may reach a length of 11 mm (0.43 in) when engorged with a blood meal, and can transmit both bacterial and viral pathogens such as the causative agents of Lyme disease and tick-borne encephalitis.

[3] Its northern limit seems to be determined by environmental factors, including temperature, since a series of mild winters in Scandinavia coincided with an expansion northwards in the range of I. ricinus.

[3] The larvae that hatch do not actively seek a host, and usually feed on insectivores (order Eulipotyphla), although they may also find rodents, rabbits, birds, reptiles, or bats.

Humans can become infected with Lyme disease, louping ill, Q fever, and tick-borne encephalitis,[3] and sensitised[9] to mammalian red meat (and derived-products), known as alpha-gal allergy.

The scientific name of the castor bean tick dates back to the starting point of zoological nomenclature, the 1758 tenth edition of Carl Linnaeus' Systema Naturae, where it appeared as Acarus ricinus.

Pierre André Latreille split the new genus Ixodes from Linnaeus' Acarus (which at that time contained all known ticks and mites), and I. ricinus was chosen as the type species.