REPRODUCTION AND SEX 553 



range. For the parent bird there may be an advantage in safe resting 

 after the reproductive strain, and in some cases it seems that the 

 brooding is linked back to conjugal sex-relations for which the nest 

 was the territorial centre. In hundreds of cases the male birds share 

 in the brooding; in some instances, as in other forms of parental 

 care, they assume the whole responsibility. 



(6) Another note is struck when the offspring remain beside their 

 parent or parents for a considerable time, receiving food, protection, 

 and instruction. 



(7) It seems useful to separate off the various expressions of 

 viviparity, especially in the big-brained mammals, where the mother 

 carries the unborn young for weeks or months, and even, in the case 

 of the elephant, for a couple of years! Yet we must admit that 

 the very careful nurture which a mother mammal often gives its 

 offspring is to begin with on an instinctive basis, and it is an in- 

 structive warning against too generous psychology to notice that 

 a ewe who has licked another's lamb may appropriate it, to the 

 detriment — sometimes fatal — of its own, as yet unborn. An inexperi- 

 enced cow, excited after delivery, may kill its newborn calf, which 

 alarms it by a sudden movement of its head. But when smell and 

 taste have served as the liberating stimuli of the instinctive routine, 

 no mother is more objectively devoted and maternal emotion shines 

 through her eyes. 



The highest expressions of parental care are to be found in those 

 cases where the offspring remain for a long time under the protection 

 and tutelage of the mother, or of both parents, and there is more 

 than a beginning of family life. 



Instinct and Intelligence. — As it seems to us, a misunder- 

 standing is apt to arise, even among experienced naturalists, when 

 instinctive and intelligent behaviour occur side by side in one and 

 the same animal, yet without the capacity for judgment or inference 

 (intelligence) being able to help the inborn chain of reflexes and their 

 correlated psychical side (instinct). Among the experiments made 

 with pigeons by the late Prof. Whitman, there were several which 

 took the form of removing the eggs from the nest during the brooding 

 bird's absence and leaving them in the immediate vicinity, within 

 reach of the nest. When the bird returned, she was apparently 

 more influenced by the sight of the nest than by the sight of the 

 eggs, and, in some cases, she ignored the eggs altogether, though it 

 would have been easy to retrieve them. We interpret this by suppos- 

 ing that the whole business of brooding has passed so completely 

 into the domain of the instinctive that it is not easy to awaken 

 intelligence in this connection, though pigeons often have much. 

 The behaviour of Whitman's pigeons varied notably according to 

 the species or variety of bird, for some were less thirled to instinct 



