namely: Themeda triandra, Digitaria macroblephara, and Pennisetum mezianum. The time spent grazing increased by about 100% during the dry season. Though the choice of the diet remained the same in both the dry and the wet season, the animals were more selective during the latter. Reproduction Male blue wildebeest become sexually mature at about 2 years of age, while females can conceive at 16 months if adequately nourished. Nevertheless, most females do not start to breed until a year later. The mating season, which lasts for about 3 weeks, coincides with the end of the rainy season. This means that the animals are in good condition, having been feeding on highly nutritious new grass growth, and the conception rate is often as high as 95%. The mating season, or rut, typically begins on the night of a full moon, suggesting that the lunar cycle influences breeding. At this time, testosterone production peaks in males, resulting in increased calling and territorial behavior. The activities of these sexually excited males may also stimulate the female to come into estrus. As they stake out their territories and compete for females, males exhibit rivalry. When they clash, they face up to each other with bent knees and exchange horn thrusts. Elaborate individual displays are made during their rivalry, and they may bellow, snort, and dig their horns into the ground. Once dominance has been established, each male attempts to lure the female into his domain. During courtship, urination and low-stretch are common activities, and the male soon attempts to mount the female. A receptive female holds her tail to one side and stands still while copulation takes place. Matings may be repeated several times and may take place twice or more times within a minute. The male neither eats nor rests when a female is present in his territory, and during this time, the female keeps close to the male, often rubbing her head on his torso and sniffing his penis. While in season, a female may visit several territories and mate with several different males. The gestation period is about 8.5 months, and between 80 and 90% of the calves are born within a 3-week time period. Female wildebeest give birth in the middle of a herd rather than alone, and typically in the middle of the day. This allows time for the newborn to become steady on its feet before night falls