Stock-Breeding Applications of Their Laws of Development and Heredity Domestic Animals - Tapa blanda

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1891. Excerpt: ... CHAPTER XYIII. PERIOD OF GESTATION. The duration of the period of gestation in mammals is apparently determined by various causes that we are as yet, from the obscurity of their action, unable to define. That it bears some relation to the size of the animal is shown by the following instances, which have been compiled from various sources;' and Mr. Darwin states that it has been observed in Germany that " the period of gestation is longer in large-sized than in small-sized breeds of cattle."1 The period of gestation is approximately as follows: Elephant, twenty to twenty-three months; giraffe, fourteen months; dromedary, twelve months; buffalo, different varieties, from ten to twelve months; ass, twelve months; mare, eleven months; cow, two hundred and eighty-five days; bear, six months; rein 1 Van Der Hoeven'a " Zoology," vol. ii.; "Economische ncugikund Verhandl," quoted in Johnson's " Farmer's Cyclopedia," and Quarterly Journal of Agriculture, vol. x., p. 287; Dunglison's " Human Physiology;" Johnson's "Cyclopaedia," article "Gestation," by Dr. E. R. Peaslee; "Encyclopaedia Britannica," article "Animal Kingdom," by Prof. Wilson. "Animals and Plants under Domestication," vol. ii., p. 387. deer, eight months; monkeys, seven months; sheep and goat, five months; sow, four months; beaver, four months; lion, one hundred and eight days; puma, seventy-nine days; dog, fox, and wolf, sixty-two to sixty-three days; cat, fifty days; rabbit, thirty days; squirrel and rat, twenty-eight days; Guinea-pig, twentyone days. A similar relation may be traced in the period of incubation in birds, which is as follows: Turkey, twenty-six to thirty days; Guinea-hen, twenty-five to twenty-six days; pea-hen, twenty-eight to thirty days; ducks, twenty-five to thirty-two days; ge...