The oestrous cycle of the spiny mouse (Acomys cahirinus).

The oestrous cycle of the spiny mouse (Acomys cahirinus), as determined by vaginal smears, is 11.1 +/- 1.9 (s.d.) days (n = 110). The vaginal smears show cell patterns similar to those seen in the rat, but secretion of mucus is greater than in the rat. The average age at vaginal opening is 45 +/- 2.77 (s.e.m.) days, but the first litter (sired by litter mates) did not occur until 103 +/- 4.04 (s.e.m.) days. The decidual response to uterine trauma indicates tha there is an active luteal phase. The ovaries are otherwise histologically similar to those of other murids.