Emperor penguin creches and altruism
Kevin C Welch, © 1999

What are penguin creches? That statement is a question which can be answered on several levels. The first level of analysis includes a descriptive and functional assay of penguin creches. Describing creches and demonstrating their purposes are subjects easily explored. The more interesting question -- and perhaps the one with an almost unattainable answer -- is what are the evolutionary and behavioural purposes of a creche? The answer to that question defies current perception of animal altruism by the general public.     Briefly, a creche is an aggregation or accumulation of penguins in close apposition or proximity, usually touching. Creches are found almost entirely in the emperor penguin populations, and they are formed by both adults and juveniles. The Antarctic climate is particularly hostile, especially in the depth of winter when temperatures can reach well below freezing. Coupled with brutal winds, the Antarctic shelves are areas in which few animals could survive. Emperor adults, while cradling their single eggs on their feet, form groups of tightly knit populations. Emperor penguin juveniles do the same thing once they are capable of being somewhat independent.     The creche is composed of a periphery (i.e., the outside) and a central portion or inner range. Capillary loss of heat travels by convection in the creche to near-by penguins where it is often sequestered. Heat lost by penguins in the periphery is just that: lost. Penguins on the periphery lose more heat than they gain, while those nearest the center retain and receive more heat. Additionally, winds and drifting snow bombard members of the periphery accelerating the heat lost by these members. Wind minimally contacts central members of the creche. Throughout the nights and coldest days while these creches exist, members of the periphery move about to the central regions and the creche appears to move en masse from its original formation spot -- gradually, that is. In summary, the creche serves as a means for staying warm. This addresses the first question.     The notion that individuals on the periphery take their turns on the outside and that members on the inside relinquish their turns at the center so that the two populations may "switch" is erroneous. It's a fairly codified hypothesis of ethology and evolution that the rule of genetic fitness and "selfish genetics" (i.e., looking out for number one) is supreme. Individual penguins are simply not willing to take turns in any of these positions in the creche; each and every one is focused on getting to the center and remaining at the center simply because each is probably uninterested in the collective survival of the group. To suggest that emperor penguins take their turns so that other penguins have a chance of staying warm is otherwise known as group selection. Group selection is a largely discounted evolutionary theory that presupposes that individuals conduct themselves to ensure the survival of the group with the subtending notion that group survival leads to individual survival. A more appropriate and correct evolutionary theory is kin selection. Kin selection hypothesizes that individuals conduct themselves in such a manner that ensures a survival of that individual as well as those related to it. In the case of emperor juveniles, each chick is the sole offspring of its parents; therefore, the emperor juvenile has no kin, per se. Hence, the emperor juvenile looks out for itself, and it most likely makes every effort to attain a central position in the creche and keep it. This is why creches appear to move; each emperor juvenile is jockeying for an optimal position in the creche.     This theory begets a few questions: if the center is such a prized location, why don't penguins fight for the center? If they are unwilling to fight, why? They're certainly valid questions and may even present caveats to the theory. Simply, fighting is always a last resort in animals. Most animals undergo extensive and ritualized displays to exert dominance before fighting. Most of these displays result in one of the two backing down. That solves part of the question. But, what about those willing to fight? With temperatures below -100 and the scarcity of food, fighting is expensive energetically and repair may not be possible under these winter conditions. With the risk of injury and loss of energy, the absence of fighting -- usually restricted to petty squabbling and flapping -- is observed since it is more appealing than a fight over a possibly better position that constantly changes. This does not, however, preclude attempts and foolery.     Those that don't achieve central positions are more likely to succumb to the weather, a demonstration of natural selection. Darwin, Charles. On Evolution. Glick & Kohn, eds. 1996. Hackett Publishing Company, Inc.: Indianapolis. Krebs, J.R. & Davies, N.B. 1993. An Introduction to Behavioural Ecology. London: Blackwell Scientific Publications. Krebs, J.R. & Davies, N.B. 1991. Behavioural Ecology: An Evolutionary Approach. London: Blackwell Scientific Publications. Young, David. 1992. The Discovery of Evolution. Cambridge Uniersity Press: Cambridge.