SCIENCE- G OSS IP. 



PARENTAL RELATIONSH IP. 



By Gerald Leighton, M.B. 



THE question of the relation of parent to off- 

 spring, in its highest development, may be 

 regarded as a problem in ethics ; but, like other 

 ethical problems, it can only be understood in its 

 origin when studied from a biological point of 

 view. Once get at the course of evolution of an 

 idea no less than of a thing, and a flood of light is 

 thrown upon all that the idea conveys. 



In the highest animals— that is, the mammalia — 

 we see the parental relationship at work every 

 day, the mother nourishing her offspring, the 

 father protecting the family. In the lowest in- 

 vertebrates there is no such thing as the relation 

 of parent to offspring, except the purely physical 

 act of some form of reproduction. At what point, 

 then, in the scale of nature did parental relation- 

 ship first show itself, and what were the conditions 

 necessary for its development ? 



The question may be put in other words, where do 

 we first see the parents taking care of their young 

 in the scale of nature 1 We have said it is a 

 familiar picture in the mammals, which indeed 

 take their name from this feature. It is seen well 

 marked too in birds, though in a less degree. 

 What about the class next below them— viz. the 

 reptiles 1 One finds in text-books on natural 

 history that some authorities deny the existence 

 of parental relations at all in reptiles. This looks 

 as if one must seek hereabouts for the first indica- 

 tion of the phenomenon. But leaving reptiles for 

 the moment, what do we find in the amphibians, 

 which come next on the scale ? Here the relation 

 of parent to offspring may be said to be non- 

 existent, the same applying to the fishes, and we 

 look in vain for any sign of it lower in nature. 

 Why is this ? No doubt, mainly for two reasons. 

 First, that the last two classes, fishes and am- 

 phibians, reproduce by spawning. In other words, 

 the offspring are not brought forth alive and 

 mature. Secondly, the fecundity of fishes and 

 amphibians is too great, the number of young from 

 each spawning being so enormous as to entirely 

 preclude any idea of parental relationship. No doubt 

 there is care shown in depositing the eggs, but 

 this is a different thing from care of offspring, for 

 the eggs once deposited are no longer an object of 

 solicitude. Now, it is quite true that some fishes 

 do bring forth their young alive and mature ; for 

 example, the viviparous blenny. Some of the sharks 

 also are viviparous, the Greenland shark being said 

 to produce only three or four young at a time ; the 

 bergylt also is viviparous ; but it is doubtful if in 

 any of these cases, which are exceptional in their 

 c ass, there is a true parental relationship. At any 

 rate here among some fishes we see the beginnings 

 of the first necessity for the development of the 

 parental fooling — viz. that the offspring shall be 



born in a form recognisable by the parent. This 

 is the first element required to build up the com- 

 plex emotion which is to appear later. 



Other factors enter into the process of the 

 development of the parental relations, but at 

 present we are considering the dawn of that 

 phenomenon in nature. We may omit the amphi- 

 bians, as they are spawning or egg- depositing 

 creatures, with few exceptions; and in nearly all 

 the young undergo a metamorphosis — i e. their 

 form at birth is not that of the adult. Next we 

 come to the reptiles, in which group, as before 

 stated, authorities differ, which in itself is an 

 indication that some have seen what others have 

 failed to observe. Theoretically considered, what 

 would one expect to find? Take the case of two 

 British reptiles, the adder and the grass-snake. 

 The former brings forth young adders, the latter 

 deposits eggs and leaves them. The adder famly 

 is, I believe, rarely more than thirteen in number ; 

 the grass-snake deposits three or four dozen eggs. 

 Therefore, following the reasoning above indicated, 

 one would suppose that one might find indications 

 of parental relations in an adder-mother, which 

 brings forth young adders, not very numerous at 

 a birth. Yet one would not look for the grass- 

 snake to show any such indication. May not this 

 be the very reason that authorities differ about the 

 reptiles, because some are viviparous and some 

 oviparous? May it not be that in the viviparous 

 reptiles parental relationship exists, while it is 

 absent in the egg-layers ? If there is anything 

 in this supposition, it is to the adder-mother 

 one must look for signs of some solicitude for 

 her young, for one has to go higher up in nature 

 to find the parental idea developed in the male. 

 One must seek to find out what steps, if any, the 

 adder-mother takes to provide food for her offspring 

 and to protect them from danger, the two direc- 

 tions in which the maternal instinct first shows 

 itself. Those who believe that the female adder 

 swallows her young for protection will at once say 

 there is a marked case of parental relationship- 

 Naturalists hardly admit that phenomenon as yet 

 proved ; therefore it is of interest from this point 

 of view that it should be definitely settled. Be 

 that as it may, it is quite evident that it is at the 

 reptile stage in nature that one would naturally 

 expect to find parental relationship first appearing, 

 since here for the first time in the scale are the 

 • young of some species habitually developed in the 

 image of the parent, and in sufficiently small 

 numbers for the mother to be capable of being of 

 use to them. When one reaches the birds, one 

 finds a great stride has been made in the develop- 

 ment of the parental idea of duty, instinctive 

 though it still is, and one may watch for hours a 

 father and mother bringing food to a nest of young, 

 and, if necessary, protecting their offspring from 

 intruders. 



Grmmont, Pontrilis, ne r Hereford. 



