Sea World presently has well-established, productive breeding program for bottlenose dolphins Tursiops truncatus killer whales Orcinus orca and Commerson's dolphins Cephalorhynchus commersoni. There have been a total of 50 bottlenose dolphin births, 7 killer whale births and 8 Commerson's dolphin births since the inception of breeding programs for these species in 1978, 1983 and 1983, respectively. In our current inventory, 48% of our bottlenose dolphins, 38.5% of our killer whales and 44.4% of our Commerson's dolphins were born in our parks. Important to the success of these breeding programs has been; 1) facility design, 2) establishment of breeding colonies around behaviorally compatible females and males, 3) husbandry practices which allow early hormonal detection of pregnancy and 4) the pre- and post-natal association of inexperienced mothers with experienced females and their calves. calves are born all year round in our facilities with some peaking in calving activity in spring and fall months. Gestation is approximately 12 months for bottlenose dolphins and Commerson's dolphins, and 17 months for killer whales. Calving intervals are 2 to 3 years in bottlenose dolphins and Commerson's dolphins and approximately 3 years in killer whales. We have undertaken extensive hormonal and behavioral monitoring of our killer whales, in particular. Serum and urine progesterone profiles for the female whales, spanning two full-term pregnancies for three of the females, have demonstrated that killer whales are spontaneous ovulators, that females are polyestrus with alternating periods of polyestrus and anestrus which vary from female to female, that progesterone levels are lower in second and third pregnancies and that the general pattern of progesterone production during pregnancy can be used to predict the time of parturition when complete hormone profiles are not available.