Thirty-three estrous cycles of three female tayras were defined using vaginal cytology and/or behavioral observations. Estrous cycles averaged 56.0 ± 4.73 and 52.2 ± 15.5 days in length for two young tayras and 93.9 ± 21.0 for an older female. The complete absence of parabasal cells in vaginal smears coincided with vulvar tumescence and was diagnostic of estrus.