The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), is considered to be one of the most significant pests of cattle worldwide. A vector for piroplasmosis, or cattle fever, the southern cattle tick is a key target of en aggressive eradication program along the U.S.-Mexico border. Endemic to subtropical and tropical regions, southern cattle ticks are limited in range by climate and temperature. Neither adults nor larvae of southern cattle tick survive more than e few days of subfreezing temperatures. Nonetheless, in a separate study of fecundity of southern cettle tick in different field conditions, where begged samples of egg masses were allowed to hatch in the field then placed in a freezer in order to estimate egg hatch, a single southern cattle tick larva was found alive following exposure to room temperature after 20 days of cold-exposure. Although quite anomalous, this report of this outlying observation suggests the possibility that southern cattle tick can survive extremely cold temperatures for long durations.