In 29 Göttingen Miniature Pig sows several behavioral parameters were recorded daily for a total of 261 sexual cycles. The sows were observed both in the absence of a male and when confronted with a mature vasectomized boar. Since most of the females had not reached puberty at the onset of the experiment it was possible to differentiate between first, second, third and later detectable cycles past puberty. Average cycle length for sexually mature young sows was 21 days. The first three cycles after puberty usually were slightly prolonged (1.6, 0.7 and 0.8 days for first, second and third cycles respectively).