Quantitative investigation of the annual pattern of follicular development in the nine-banded armadillo (Dasypus novemcinctus).

Mature, non-pregnant, female armadillos (Dasypus novemcinctus) were killed throughout the year (3-6/month, N = 54) and both ovaries were examined for follicular development. All normal and atretic follicles > 358 micrometers were counte. Total number of normal follicles remained constant from January to June but decreased by 50% in the remaining months except in October and November. Follicles > 978 micrometer (those likely to be ovulated) were found during each month but more (> 3/ovary) were present during April, May, June and October. Atretic follicles remained constant (4-6) except in July and August when the number (10-12) was doubled. A single CL was present in 2/4, 6/6, 1/6, 1/3 and 2/3 animals in July, August, October, November and December, respectively. These data confirm that armadillos ovulate in July and suggest that ovulation may also occur in some animals in late October or November.