Two non-lactating, non-gravid female bottlenose dolphins Tursiops truncatus (SLA and TOD) began lactating within one week after being put with orphan calves. In the first case, the female produced milk with sufficient nutrients to provide for a majority of the calories required by the calf for growth. In the second case, milk has not yet been analyzed but nursing has apparently provided a significant nutritional benefit to the calf. SLA, age 33, 262cm, 202kg, has been kept by our laboratory since 1967. In 1979 she produced and reared a calf which was weaned in 1981 (the 1979 calf produced her own offspring in 1991). From 1981 until 1992 SLA was neither lactating nor pregnant as confirmed by analysis of blood samples which were taken at approximately six-month intervals for health assessment and progesterone determination. In October, 1992, SLA was placed with an unrelated six-month-old, 46kg calf that had been attempted to nurse on SLA despite being fed formula six times each day. The calf persisted in nursing and SLA cooperated, thus on the eighth day we tried to milk SLA. A sufficient quantity of milk was obtained for analysis; it contained 9.1% fat and 8.6% protein. This milk contained considerably less fat than average Tursiops milk but was two to three times as rich as bovine milk. As lactation continued we took milk samples at least weekly. From the milk appearance, we suspect that the fat content increased considerably but those analyses are not yet complete. At 12 months of age, the male orphan calf weighed 88 kg and was still nursing while taking about 2kg of fish per day. We estimate that SLA continues to provide more than half of the daily calorie requirements for the calf. TOD, age 36, 268cm, 205kg, has been with our laboratory since 1968. She never calved and pregnancy has never been detected during biennial physical examinations. TOD began lactating soon after being placed with the 73kg orphan. A milk sample was collected on day five and stored for later analysis. At 12 months of age, this orphaned calf weighed 86kg, was eating 4kg of fish daily, and continuing to nurse.