Rut (mammalian reproduction)
The rut (from the Latin rugire, meaning "to roar") is the mating season of certain mammals, which includes ruminants such as deer, sheep, camels, goats, pronghorns, bison, giraffes and antelopes, and extends to others such as skunks and elephants.
[1] The males of the species may mark themselves with mud, undergo physiological changes or perform characteristic displays in order to make themselves more visually appealing to the females.
For different species, the timing of the rut depends on the length of the gestation period (pregnancy), usually occurring so the young are born in the spring.
The rut for white-tailed deer (Odocoileus virginianus) usually lasts three weeks in the Northern Hemisphere and may occur most of the year in tropical zones.
When the climate is extremely cold, a buck will sometimes resort to swamps and bogs, because of the warmer temperatures these areas hold.
[14] During the rut, elk frequently use areas around fresh water, and tend to bed in heavy timber five to six hours per day.
[17] The function behind this acoustic structure of the bugle is directly correlated to the male's physiology and how different frequencies travel through varied environments.
[16]: 229 The reason for the high-frequency portion of the bugle is due to the propagative efficiency of differing frequencies through varying environments.
Studies have shown that as a bull's harem increases in diameter, meaning the cows become more dispersed, he tends to vocalize more frequently than if they were within closer proximity.
[21] The higher-pitched section of the call propagates through the environment better, which is why the bull uses it to congregate a harem that is becoming more spatially dispersed and thus harder to defend.
[22] As explained above, this is because larger body mass positively correlates with longer vocal folds and thus lower frequency emission.
[22] Bull elk overcome this by a unique anatomical mechanism that produces sound using a different pathway than the vibrations of the vocal folds.
[23] Bull elk constrict their supra laryngeal vocal tract, specifically in the nasal cavity in order to create a smaller opening for exhaled air to pass through.
[23] As air moves through this opening it causes the tissues to vibrate and produce the high frequency sound waves which comprise the "whistle" portion of the bugle.
[24] This anatomical development for bioacoustics in elk was discovered upon sonographic analysis of bugle vocalizations which revealed a biphonetic (two simultaneous frequencies) display.
"Yelping commonly was accompanied by contractions of the penile region with simultaneous emission of short spurts of urine.
The most prominent characteristics of an elephant in rut are heightened sexual and aggressive activity along with copious temporal gland secretion and continual urine discharge.
[1][31] Also it has been observed that males will have a higher concentration of testosterone and an increased likelihood of associating with female groups during musth.
Similarly to deer or mountain goats, elephants will tusk the ground throwing vegetation, logs and objects into the air and occasionally at subordinates.
This is a display meant to scare away other rival males where the bull moose will destroy trees and vegetation prior to engaging in a fight.
[34] Furthermore, as seen in other deer species male moose will dig mud pits and soak them in urine and the females will fight over possession of these wallows.
[33] During this stage there is much mock fighting and the pre-rut ends in September when the bull moose emerge from the solidarity of heavily wooded areas.
Following the mating season, bull moose spend long hours resting and feeding before forming their usual winter groupings.
