Editing Wildebeest (section)

===Breeding and reproduction===
[[File:Drink From Mom Wildebeest.ogv|thumb|Video of a wildebeest feeding its calf]]

Wildebeest do not form permanent pair bonds and during the mating season, or [[rut (mammalian reproduction)|rut]], the males establish temporary territories and try to attract females into them. These small territories are about {{convert|3000|m2|sqft acre|||}}, with up to 300 territories per {{convert|1|km2|sqmi acre|||}}. The males defend these territories from other males while competing for females that are coming into oestrus. The males use grunts and distinctive behaviour to entice females into their territories. Wildebeest usually breed at the end of the rainy season when the animals are well fed and at their peak of fitness.<ref name=ulfstrand /> This usually occurs between May and July, and birthing usually takes place between January and March, at the start of the wet season. Wildebeest females breed seasonally and ovulate spontaneously.<ref name=Clay>{{cite journal|last=Clay|first=A. Moss|author2=Estes, R. D.|author3=Thompson, K. V.|author4=Wildt, D. E.|author5=Monfort, S. L.|title=Endocrine Patterns of the Estrous Cycle and Pregnancy of Wildebeest in the Serengeti Ecosystem|journal=General and Comparative Endocrinology |year=2010 |volume=166 |issue=2 |pages=365–371|doi=10.1016/j.ygcen.2009.12.005|pmid=20036667}}</ref>

The [[estrous cycle]] is about 23 days and the gestation period lasts 250 to 260 days. The calves weigh about {{convert|21|kg|0|abbr=on}} at birth<ref name=Benirschke/> and scramble to their feet within minutes, being able to move with the herd soon afterwards,<ref name="National geographic"/> a fact on which their survival relies.<ref>{{cite web |url=https://wildlifetv.wordpress.com/2013/05/11/how-do-baby-wildebeest-survive/ |title=How do baby Wildebeest survive? |date=11 May 2013 |publisher=Wildlife TV |access-date=7 October 2017}}</ref> The main predator of the calves is the [[spotted hyena]]. The calving peak period lasts for 2–3 weeks, and in small subpopulations and isolated groups, mortality of calves may be as high as 50%. However, in larger aggregations, or small groups living near large herds, mortality rates may be under 20%.<ref>{{cite journal |author=Estes, Richard D. |year=1976 |title=The significance of breeding synchrony in the wildebeest |journal=African Journal of Ecology |volume=14 |issue=2 |pages=135–152 |doi=10.1111/j.1365-2028.1976.tb00158.x}}</ref>

Groups of wildebeest females and young live in the small areas established by the male. When groups of wildebeest join, the female to male ratio is higher because the females choose to move to the areas held by a smaller number of males.<ref name=Thaker /> This female-dominated sex ratio may be due to illegal hunting and human disturbance, with higher male mortality having been attributed to hunting.<ref name=Nidablema>{{cite journal |last=Ndibalema |first=Vedasto G.|title=A comparison of sex ratio, birth periods and calf survival among Serengeti wildebeest sub-populations, Tanzania |journal=African Journal of Ecology |year=2009 |volume=47 |issue=4 |pages=574–582 |doi=10.1111/j.1365-2028.2008.00994.x}}</ref>