Search results
Results from the WOW.Com Content Network
Estrous cycle variability differs among species, but cycles are typically more frequent in smaller animals. Even within species significant variability can be observed, thus cats may undergo an estrous cycle of 3 to 7 weeks. [15] Domestication can affect estrous cycles due to changes in the environment.
The specific voluntary crowding of rats to which the term "behavioral sink" refers is thought to have resulted from the earlier involuntary crowding: individual rats became so used to the proximity of others while eating that they began to associate feeding with the company of other rats.
The second signal is released during the ovulatory phase of the estrous cycle and it lengthens estrous cycles. When rats live together or share the same air supply, the pheromones released by each female in a group as a function of the phase of her estrous cycle causes other females in the group to either lengthen or shorten their estrous cycles.
The original experiments with rats applied the following protocol: A male rat was placed into an enclosed large box with four or five female rats in heat. [13] He immediately began to mate with all the female rats repeatedly until he eventually became exhausted. [13] The females continued nudging and licking him, yet he did not respond. [13]
The follicular phase, also known as the preovulatory phase or proliferative phase, [1] is the phase of the estrous cycle (or, in primates [2] for example, the menstrual cycle) during which follicles in the ovary mature from primary follicle to a fully mature Graafian follicle.
The second breeding phase of the rut takes place three to four weeks after the first breeding phase. This is due to younger cows coming into estrus, as well as older cows that were not bred on their first estrus cycle coming back into estrus. Herd bulls are less aggressive towards satellite bulls at this phase in the rut due to exhaustion. [13]
A marsupial has a short gestation period, typically shorter than its estrous cycle, and gives birth to an underdeveloped newborn that then undergoes further development; in many species, this takes place within a pouch-like sac, the marsupium, located in the front of the mother's abdomen.
In biology, a biological life cycle (or just life cycle when the biological context is clear) is a series of stages of the life of an organism, that begins as a zygote, often in an egg, and concludes as an adult that reproduces, producing an offspring in the form of a new zygote which then itself goes through the same series of stages, the ...