Most of the 88 Carios spp are species-specific parasites of bats and rodents. Several species infest birds nesting in rocks and caves. These ticks normally live alongside their hosts in caves, hollow trees, and rock crevices, and therefore rarely come in contact with domestic animals. However, in locations where bats occupy roof cavities, their parasites may present a problem for people and their pets. Ticks C kelleyi in North America and C vespertilionis in Europe, which in nature feed almost exclusively on rock- and tree-roosting bats, have been found in massive numbers in homes with associated bat colonies and have been reported to attach to people. Nest parasites of colonial birds such as C amblus, C capensis, and C denmarki may pose a distinct threat to breeding colonies and are known to cause the death of chicks.
