5. Different Forms of Parental Care. The ways in 

 which parents may help their immature young are almost 

 as varied as are the plants and animals themselves. There 

 are, however, certain classes of caretaking that are 

 conspicuous because they are found so often. Thus we 

 note the storing up of extra food in the eggs, as in 

 reptiles and birds. Eggs may be laid where an abundance 

 of food will be found as soon as they are hatched, 

 as in flies, beetles, and many other insects. Parents 

 may give aid in hatching, by carrying the eggs 

 around attached to the body, as in lobsters, or by 

 incubation, as in birds, or by carrying the eggs and young 

 in the body during early development, as in the higher 

 plants, some sharks, some snakes, and all the mammals 

 with a few exceptions. Special protection may be 

 furnished the young after hatching, as by the coats of 

 seeds, and by active efforts, as in many of the higher 

 animals. Birds capture food for their young, and the 

 mammals secrete it in the form of milk. Special education 

 of the young through imitation and other faculties is seen 

 in birds and many mammals. 



It is not our purpose to dwell at length on the different 

 forms which the care of parents for offspring may take. 

 But it is our purpose to make clear that this kind of care 

 after reproduction makes it possible to diminish the 

 original cost to the parent in substance. When bacteria 

 divide into two half-sized individuals, the daughter cells 

 have as much substance of the parent as is possible, but 

 there is no parent left to give them any care. This is 

 successful. No group is more successful on its plane of 

 living than the bacteria. At the other extreme we have 

 man, in whom the embryo has very little endowment in 

 the egg itself, but has the maximum of parental care, in 

 that it is carried in the body, is supplied with food, and 

 receives definite protection and education for a long period 

 after birth. Men can keep the species up, that is, each 

 family can bring two to maturity on the average, with a 

 birth rate of three or four during the generation. 



6. Effects of Parental Care in Higher Forms. There 

 are several things, especially important in human life, 

 that grow out of this increasing care of parents for the 

 young after hatching or birth. These things have great 

 influence on the species and on the relations of individuals. 



In the first place, the period of infancy and helplessness 

 grows longer and longer as we ascend the scale of life. 

 The higher the parent physically and mentally, the more 

 difference there is between the offspring and the mature 

 parent; the further the offspring have to go in their 

 development. Thus there is the more need for parental 

 care, and the more opportunity for education. This makes 

 it possible for the young to progress faster and more 

 safely than if they had to learn every thing through their 

 own experiences. 



Secondly, the care of young tends to hold the parents 

 together. This is true during the breeding season at least, 

 and thus something of a home or social life is developed. 

 We see this among ants, bees, birds, and the higher 

 mammals. There is no doubt that this adds to the 

 efficiency of a species. 



In the third place, the long period of dependence of the 

 young on the parents tends to develop in the parents 

 themselves the qualities that make better parents of them. 

 Anything that increases their sympathy and disposition 

 to make sacrifices for the offspring will react on the 

 welfare of the offspring and for the good of the species. 

 It is possible that the good points of parents themselves 

 have thus been increased from generation to generation. 



The highest human sentiments cluster about marriage, 

 parenthood, and care of young, and these play a most 

 important part in the progress of mankind socially and 



morally. Indeed all social progress is closely related to 

 these fundamental capacities and tendencies in connection 

 with reproduction and care of young. 



CHAPTER TWENTY-ONE. 

 REPRODUCTIVE INSTINCTS. 



1. Introduction. Thus far we have been speaking of 

 reproduction chiefly as a process found in different 

 individuals whereby they increase the number of the 

 species. Reproduction thus viewed seems to be a result 

 that can be had by a number of different kinds of 

 machinery, much as we may cultivate corn with a crooked 

 stick, or with a hoe, a single plow, or an up-to-date 

 cultivator. The methods differ in efficiency, but all lead 

 to the same result. The real meaning of the process is 

 very much the same whatever method is used. 



2. Tendencies in Life. It does not explain the fact of 

 reproduction, however, merely to say that the species, 

 would die out if the individuals do not reproduce. What 

 difference does it make to the individual if the species 

 does die out? We cannot imagine that the individual 

 plant or animal is conscious of this fact, or that 

 it is directly influenced in its behavior by this fact. Deep 

 within the living thing is the tendency to grow, and equally 

 the tendency to divide. We have no real explanation of 

 how it comes to be, but we do know that as we ascend the 

 scale of life the process of reproduction becomes more and 

 more complex. There come also to be various tendencies 

 in plants and animals, associated with reproduction, that 

 we describe as habits or instincts. Some of these are 

 peculiarly important and interesting, and help make 

 reproduction more efficient. 



3. The Meaning of Instincts. If an individual learns to 

 do a certain thing and does it so often as to come to do it 

 readily and without conscious attention we say it has 

 become a habit. If an individual inherits a tendency to 

 do a thing a certain way, and this tendency thus belongs 

 to the whole species we say it is an instinct. Instincts are 

 thus more deeply ingrained into life than habits are. They 

 are not "learned." 



The great vital acts, like feeding, adapting one's self to 

 climatic conditions, and mating and reproducing are 

 surrounded by instincts such as have been described. If 

 an infant is hungry, it instinctively cries and seeks for its 

 food. If a particle of food is placed on the back of its 

 tongue it automatically and instinctively swallows. It is 

 very certain that food-getting, adjustment to cold, mating, 

 and reproduction could not possibly take place in plants 

 and animals with any such precision as we have seen, if 

 it were not for these deep instincts, and if every animal 

 had to learn independently to do everything for itself. 



4. Somie of the Instincts Connected with Reproduction. 

 The instincts that tend to make reproduction certain and 

 efficient are of three classes: 



(1) The instinct of reproduction itself, which in a 

 purely unconscious way prompts the animal, when it 

 begins to approach maturity, to form the reproductive 

 bodies. These are the deepest of all these instincts. Indeed 

 they are so deep that we know very little about just how 

 they work. 



(2) The instincts connected with mating, which bring 

 the sex cells together so that they may unite. 



