FASTING DURING THE MATING SEASON

That some animals fast during the mating season is well known, but our knowledge of the living habits of the animal kingdom is so meager that it is not known how many animals do so. So far as it is at present known, fasting during the breeding season is very rare among mammals and birds. Among mammals where there is keen competition between the males for possession of the females, feeding is curtailed, but this is hardly a fast.

Quite a number of fishes fast during the breeding season, the female of the Cichlidae, or mouth breeders, must fast at this time.--See History of Fishes, by J. R. Norman. The best known example of fasting by fish during the mating season is that of the long fast of the male salmon. Prof. Morgulis describes in these words, the annual fast of the salmon: "At the time they commence to migrate from the sea towards the streams, their muscles are thoroughly encumbered with huge masses of fat. Fasting all their journey, which lasts many weeks and months, they are in a much emaciated condition when they get to the upper reaches of the rivers where the currents are rough and swift. Freed from the fat, however, their muscles are now agile and nimble, and it is at this time that the salmon displays the marvellous endurance and skill admired by all sportsmen, in progressing steadily against all odds of the tumultuous current, waterfalls and obstructions."

Penguins and the male goose are the only birds I find mentioned as fasting during the mating season. The gander loses about one-fourth of his body-weight during this period. George G. Goodwin, Associate Curator, Department of Mammals, The American Museum of Natural History, New York, says: "It is questionable if any of the birds are capable of a prolonged fast--their rate of metabolism is too high. I have never heard that a gander fasted during the mating season and am inclined to question such a statement."

The basis of his questioning is not very solid; he has never heard of it. It may be assumed that if it were true he would have heard of it, but no man knows everything in biology and this is out of his special field. The other part of his objection, the high rate of metabolism of birds, is no basis at all. It only reveals that he knows little of fasting. It is not likely that the rate of metabolism of the male salmon is low while he swims hundreds of miles up-stream. His a priori doubts must be considered, they are not to be taken as final.

The Alaskan fur seal bull is the best known example of fasting by a mammal during the mating season. I have no information on the rate of metabolism in this mammal, but I think we are safe in assuming that, since he is a warm blooded animal and, at the same time, extremely active during the whole of the fasting period, his metabolic rate is high. During the entire three months breeding season of each year, the Alaskan fur seal bull does not eat nor drink (although within easy reach of abundant food) from May or the middle of June to the end of July or early days of August. After fighting for his place on the shore and for his harem of from five to sixty females, the male seal spends the summer fighting to keep his harem together and to keep his girls satisfied. Ray Chapman Andrews says, in his End of the Earth; "All through the summer he neither eats nor sleeps. It is just one long debauch of fighting and love-making and guarding his harem against unscrupulous invaders."

As a result of all this activity, Mr. Andrews says that "by September he is a wreck of his former self. All his fat has disappeared, for that is what he has been living on by absorption all summer. His bones protrude, his side is torn and scarred, he is weary unto death. Blessed sleep is what he needs. Forsaking his harem, he waddles back into the long grass far away from the beach, there to stretch out in the warm sun. He will sleep for three weeks on end without waking, if undisturbed."

After long months of incessant physical and sexual activity, without food, the seal thinks first of rest and sleep. Food may be had after the long sleep. With man, also, despite popular prejudices to the contrary, there are times when rest is of more importance than food.

The sea lion also fasts during the mating season. Although less tempestuous, the domestic life of the sea lion is described as being very similar to that of the fur seals. Coming ashore sometime between the middle of May and early June, the summer is spent in fasting and sexual activities. By the end of summer, the master of the harem is exhausted and has lost much weight, but is still able to wearily slip down the sloping beach into the sea, where a few months of fat living restore his emaciated form. The exertions of these sea lions, both sexual and physical, as they fight much, is described as tremendous. I have no information as to whether they, like the fur-seal bull, go without water during this period.

What may be regarded as fasting during the mating season is the phenomenon seen among many insects which have but a short adult life. The caterpillar does little else than eat. In certain species, after it becomes a butterfly, it never eats at all. Fabre showed that some insects have no provision for hunger, the digestive organs being absent in the fullest developed insects. Perhaps such short-lived species as ephemera should not be considered in this connection. These insects come into the world in the evening, mate, the female lays her eggs and by morning both sexes are dead without ever having seen the sun. Destined for little else than reproduction, they have no mouths and do not eat, neither do they drink. But the peacock butterfly, which often travels for miles in search of a mate and lives for a few days, though it has the merest semblance of a digestive apparatus, does not eat. The insect world presents us with many examples of this kind.

Date: 2015-01-11; view: 785