Mating behaviour and hierarchy among male warthogs (Phacochoerus africanus) in Kenya

Abstract: Warthogs live under natural conditions in matriarchal groups, bachelor groups and yearling groups. Just like all pig species do warthogs have a complex behaviour repertoire. The semi-wild warthog population at Kichwa Tembo Lodge, outside Masai Mara National Reserve, lives in a fenced area with access to food all over the year and is protected from predators. The aim of this study was to observe the male warthogs’ mating behaviour and their hierarchy during the mating season. I identified eight males and observed their behaviour for five days, using continuous sampling.To calculate the boars' hierarchy I designed an index by summing how many times they had performed the behaviours attack, defend, threat and walk away. With the help of that score I ranked the boars. The two most successful boars in terms of mating had two completely different strategies towards other boars. One was an aggressive one whereas the other one was a sneaker, avoiding other boars. I found that a behaviour called tractor sound, a sound used by males possible to court females, strongly was correlated with courtship (r=0.932; p=0.001). The boar pressing his head against the sow's back was strongly correlated with copulating (r=0.953; p<0.001). This means that these behaviours occur when boars are courtesan sows. The behaviours that are most significant to courtesan and copulating are tractor sound and head against back. There is definitely a hierarchy among the boars during mating season.