#lateralrelatives

According to kin selection theory, herds can only form when animals are related to each other and when affiliation between individuals is proportional to the closeness of genetic relatedness. It would be expected that this should require each animal to be able to recognize its closest kin. This raises a difficulty with many ungulates who separate into distinct bachelor and nursery herds. The males only meet up with the females at mating time and, therefore, are absent at the time of the birth of the next generation. It is doubtful that they even understand that mating gives rise to new infants. Moreover, they only meet the new crop of juveniles of either gender briefly at the next mating season when their attention is directed to the opportunities of mating presented by the ewes. Therefore, mature males have no reason to speculate on the identity of their progeny or any other potential juvenile relatives and it may be considered unlikely that they experience a sudden recognition of kinship when the newly mature males join the bachelor herds. The picture is more favorable for the ewes to recognize and respond to immediate relatives, since at least they know their own progeny and may be familiar with lateral relatives who remain in their established territory throughout their lives. A potential solution to the problem of recognition has been offered by the supposition that the animals do not need to know their relatives as long as the aggregate is in practice composed of closely related individuals. The argument is that a subject might be attracted to all of the other members of the herd. This may be true, but it dilutes the impact of the hypothesis by making kinship an approximation rather than a necessity. Nevertheless, there are costs to this particular version of kin affiliation. Dawkins, in The Selfish Gene, employed field data provided by Brian Bertram to present the scenario of a pride of lions composed of seven resident lionesses and two lions who are itinerant. With further reasonable assumptions, the average relatedness of the males was computed to be 0.22 and that of the females to be 0.15. The measure of social affinity between two females of unknown relatedness is slightly less than a third of what might be achieved with a full sister, had she been able to detect her kinship. The figure of relatedness for the males is less than half that of a full brother. If a choice must be made to engage in social behavior with another animal, there are clear advantages to knowing its degree of relatedness.   The arguments discussed here are yet one more example of proponents justifying kin selection by introducing an additional interpretation, that the degree of relatedness is that of the herd rather than the individual. In effect, they are arguing that measurements of relatedness are irrelevant to the theory (which explicitly places kinship at its center). We will see later that more sophisticated measurements do not support even this speculation. I have not discussed yet another apologia of the theory, that animals may detect their kin by smell. Read the full article