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.