Composition of the Milk from Zalophus californianus, the California Sea Lion

The milk of Zalophus californianus is similar to that of other marine mammals. The chief protein of the milk is casein, which has a lower phosphorus content than bovine casein. There appears to be a complete absence of lactose, and it is believed that this is the first unequivocal demonstration of the absence of lactose from the milk of any mammal.