The relations of the sexes are thus of a very intimate character, male and female keeping together not only during the breeding season, but also after it. Nay, most birds, with the exception of those belonging to the Gallinaceous family, when pairing, do so once for all till either one or the other dies. And Dr. Brehm is so filled with admiration for their exemplary family life, that he enthusiastically declares that “real genuine marriage can only be found among birds.”[20] This certainly cannot be said of most of the Mammals. The mother is, indeed, very ardently concerned for the welfare of her young, generally nursing them with the utmost affection, but this is by no means the case with the father. There are cases in which he acts as an enemy of his own progeny. But there are not wanting instances to the contrary, the connections between the sexes, though generally restricted to the time of the rut, being, with several species of a more durable character. This is the case with whales,[21] seals,[22] the hippopotamus,[23] the _Cervus campestris_,[24] gazelles,[25] the _Neotragus Hemprichii_ and other small antelopes,[26] reindeer,[27] the _Hydromus coypus_,[28] squirrels,[29] moles,[30] the ichneumon,[31] and some carnivorous animals, as a few cats and martens,[32] the yaguarundi in South America,[33] the _Canis Brasiliensis_,[34] and possibly also the wolf.[35] Among all these animals the sexes remain together even after the birth of the young, the male being the protector of the family. What among lower Mammals is an exception, is among the Quadrumana a rule. The natives of Madagascar relate that in some species of the Prosimii, male and female nurse their young in common[36]—a statement, however, which has not yet been proved to be true. The mirikina (_Nyctipithecus trivirgatus_) seems, according to Rengger, to live in pairs throughout the whole year, for, whatever the season, a male and a female are always found together.[37] Of the _Mycetes Caraya_, _Cebus Azarae_,[38] and _Ateles paniscus_,[39] single individuals are very seldom, or never, seen, whole families being generally met with. Among the Arctopitheci,[40] the male parent is expressly said to assist the female in taking care of the young ones.