The old bulls are very generally solitary for a considerable portion of the year, but return to the herds during the pairing season.
It has been suggested that synapsis may be connected with the early longitudinal splitting of the thread or with the pairing of the chromosomes, but it is possible that it may be connected with the transference of nucleolar substance to the nuclear thread.
It seems to be fairly well established that in the meiotic phase there is a truequalitative division brought about by the pairing of the chromosomes during synapsis, and the subsequent separation of whole chromosomes to the daughter nuclei.
During pairing he thrusts the tip of these organs into the seminal vesicles of the female and the eggs are fertilized as they pass out of the oviduct.
Owing to the smaller size of the male and the greater voracity of the female, the male makes his advances to his mate at the risk of his life and is not infrequently killed and eaten by her either before or after pairing has been effected.
In the male, moreover, the pincers are caliper-like and toothed at the base, whereas in the female they are untoothed and only lightly curved at the tip. These differences suggest that the pincers aid in the pairing of the sexes.
Pairing takes place in August, but the fawns are not born till the following May.
The pairing time of the squirrel is from February to April; and after a period of gestation of about thirty days the female brings forth from three to nine young.
The natural song of the canary is loud and clear; and in their native groves the males, especially during the pairing season, pour forth their song with such ardour as sometimes to burst the delicate vessels of the throat.
Long after pairing the female gives birth to living young.
The cry of this great cat, which is heard at night, and most frequently during the pairing season, is deep and hoarse in tone, and consists of the sound pu, pu, often repeated.
Hares are remarkably prolific, pairing when scarcely a year old, and the female bringing forth several broods in the year, each consisting of from two to five leverets (from the Fr.
The testes in the pairing-season form projections in the groins, but (except in the Duplicidentata) do not completely leave the cavity of the abdomen.
The lion appears to be monogamous, a single male and female continuing attached to each other irrespectively of the pairing season.
Pairing and oviposition take place on land; the male seizes the female round the waist.
Taking each leaf of his series, with an assigned number of veins, he has determined the array of pairs of leaves which can be formed by pairing the chosen leaf with all others from its own tree in succession.
In the deer of the sambar group, where the antlers never advance beyond a three-tined type, the shedding is frequently, if not invariably, very irregular; but in the majority at least of the species with complex antlers the replacement is annual, the new appendages attaining their full development immediately before the pairing-season.