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There have been both successful and unsuccessful examples of interspecific pregnancy in a multitude of different animals: “alpaca and lama (Godke 2001), cow (Bos taurus) and zebu (Bos indicus; Summers et al. 1983), banteng (Bos javanicus) and cow (Bos taurus; Solti et al. 2000), horse, donkey, Przewalski’s horse and Grant’s zebra (Summers ...
The brains of pregnant females carrying male fetuses may be shielded from the masculinizing effects of androgen through the action of sex hormone-binding globulin. [117] The relationship between sex differences in the brain and human behavior is a subject of controversy in psychology and society at large.
Horses mate in spring and summer; autumn is a transition time, and anestrus occurs during winter. A feature of the fertility cycle of horses and other large herd animals is that it is usually affected by the seasons. The number of hours daily that light enters the eye of the animal affects the brain, which governs the release of certain ...
In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. Fertilization is the fusion of two gametes . [ 1 ] Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization . [ 2 ]
Pregnant male seahorse. Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes and males producing smaller gametes ().
"Animal domestication, in general, changed human history, but no other animal was a king-maker as the horse was," said evolutionary biologist Pablo Librado of the Institute of Evolutionary Biology ...
Large mammals, such as primates, cattle, horses, some antelopes, giraffes, hippopotamuses, rhinoceroses, elephants, seals, whales, dolphins, and porpoises, generally are pregnant with one offspring at a time, although they may have twin or multiple births on occasion.
Pregnant scorpion. In viviparous animals, the embryo develops inside the body of the mother, as opposed to outside in an egg . The mother then gives live birth. The less developed form of viviparity is called ovoviviparity, in which the mother carries embryos inside eggs. Most vipers exhibit ovoviviparity. [15]