... The gorilla breeds about December, a cool and dry month: according to my bushmen, the period of gestation is between five and six months... 
Richard F. Burton 「Two Trips to Gorilla Land and the Cataracts of the Congo Volume 1」
...Theyproduce early, but are not completely adult for four or five years;the period of gestation is seven months...
Robert A. Sterndale 「Natural History of the Mammalia of India and Ceylon」
...
The female usually produces one kid in the autumn, about Septemberor October, and the period of gestation is about seven months...
Robert A. Sterndale 「Natural History of the Mammalia of India and Ceylon」
...The period of gestation seems to be about the same as that of thedomestic cow, and the greatest number of calves are born in thesummer...
Robert A. Sterndale 「Natural History of the Mammalia of India and Ceylon」
...Since activity, digestion, and gestation depend upon adequate internal temperatures, there must be a process by which these temperatures are attained and for an appropriate time maintained...
Ray D. Burkett 「Natural History of Cottonmouth Moccasin, Agkistrodon piscovorus (Reptilia)」
...The periodof gestation being about nine weeks...
A. R. Harding 「Fur Farming」
...Virginia deer are polygamous, likecattle; the rutting season is in November; the period of gestation isabout seven months, and the fawns are born in May or June...
A. R. Harding 「Fur Farming」
...It has been objected that our domestic dogs cannot be descended from wolves or jackals, because their periods of gestation are different...
Charles Darwin 「The Variation of Animals and Plants Under Domestication, Vol. I.」
... differ in their average period of gestation...
Charles Darwin 「The Variation of Animals and Plants Under Domestication, Vol. I.」
...Hunter found that the gestation of a mongrel from wolf and dog ('Phil...
Charles Darwin 「The Variation of Animals and Plants Under Domestication, Vol. I.」
...The period of gestation is from 65 to 70 days...
A. C. Smith 「The Raising and Care of Guinea Pigs」
...In a loose,pendent abdomen in the latter months of gestation the skin may often be seenpushed out at a sharp angle, irrespective of the period of drinking...
U.S. Department of Agriculture 「Special Report on Diseases of Cattle」
...The period of gestation is said to be twelve months, and they bringforth usually in August...
George Vasey 「Delineations of the Ox Tribe」
...The length of the gestation period of spectabilis is unknown...
Charles T. Vorhies and Walter P. Taylor 「Life History of the Kangaroo Rat」
...In the season of love, and during the period of gestation, they are met with only in pairs—a male and female...
Mayne Reid 「The Hunters' Feast」
...How it copulates,those who pretend to have seen disagree in their accounts: nor dowe know how long the period of gestation lasts...
Watkin Tench 「A Complete Account of the Settlement at Port Jackson」
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