Kings of Kruger

Records and assessment of 46 year study of predator-prey size relationships within South Africa indicate Lion’s are king. Loins are dominant, as the largest carnivore, consuming the widest range of prey size and species. In addition predators select prey that is approximately half to twice their own size but prey over 1000kg are relatively free of predation. 2

Lions are the most dominant predator contributing to a wide range of prey kills says N. Owen-Smith and M.G.L. Mills. In their recent paper, in Journal of Animal Ecology, the examination of a 46 year database, of prey carcasses and who killed them, suggests that there is a relationship between different predators and their selected type and size of prey. The understanding of large carnivore feeding ecology is essential to develop knowledge of carnivore behavioural ecology. 1 This study adds to the knowledge for the analysis of food web linkages as well as predator-prey relationships for other similar studies.

KrugerNational parkis located in the north-east South Africa; it is home to a wide diversity of different animals from cheetahs to warthogs to giraffes. This study examines prey preferences as well as dietary niches of the five main predators, within Kruger, consisting of lions, leopards, cheetahs, African wild dogs and spotted hyenas. These predators hunt 22 different types of prey species including impala, zebra and kudu. Examination of the carcasses by assessing what prey is it, who killed it, as well as how big is it and, if identifiable, what its age is and its sex. 49,463 carcasses were recorded with 47,829 killed by predators, of which data was recorded over many years by wardens and park ranger, for it now to be interpreted.2

Secondly lions only consume 14% of impala and similar sized prey, compared to the 50% hyenas and 70-85% dietary contribution to the other carnivores. 2 The results show that each predator have different dietary contributions suggesting that some herbivores species are less likely to be killed by some carnivores and more by others. For example lions are the most likely to kill wildebeest because they are too big to be killed by the smaller carnivores.Food webs are generally difficult to collect and analyse sufficient information but the large mammal predator-prey relationships is simpler to examine. Firstly the distribution of kill sizes show that predation on herbivore like impala, around 40kg, where dominantly killed by all carnivore, however lion kill were less than their abundance of this particular sized prey. As lions kills where generally larger, between 100-900kg, compared to the others predators killing prey less than 100kg. 2

Thirdly biomass structure shows that lions control over half the biomass, with hyenas in second through hunting and scavenging, this is due to lions spreading their dietary consumption widely over many different sizes and types of herbivores. This is emphasised in figure 1. 2 The other carnivores focus on impala-sized species apart from leopards which incur most of the small antelope kills. 65% of prey biomass is killed by the lion population. 2

The carcass records where adjustments to account for bias against small prey and under-representation of hyena kills due to scavenging from lions as well as other adjustments made to dietary contribution of lions stomach content.2

Finally lions appetites were commonly consuming 8 species out of 15 prey species available but 11 of those species where unlikely to be eaten by any of the other predator. Lioness prey selections seem to be strongly selected toward abundant prey of 60-250kg which is half to more than twice the size of a lioness (125kg). 2 Prey species under 20kg have reduced predation by lions due to their agility and prey over 1000kg is 10 times bigger than a lion and is therefore difficult to predate. 2

The smaller predators focused on prey which was below the favoured lions prey size with leopard concentrating on species 15% below it body mass. 2Apart from the overlap of prey size, the prey species killed by the different predators seems to be distinct showing prey preference. Social predation such as the lions and wild dogs showed selection towards prey larger than the predator’s size compared to solitary carnivores such as leopards and cheetahs.2

This study indicates that over a long period of time, direct observation can be examined beneficially for the understanding of predator-prey relationship within a food web. It has show that predators are bias to certain prey sizes as well as predators having different preferred prey species. The lions are shown to be dominant due them having a wide prey species range, in addition to high proportions of prey kills. 2 However adjustments were made to prevent bias but could this have been avoided by more intense examination of small prey as well as intensifying observation of hyena kills and scavenging. It is questionably but the method undertaken of carcass observation does indicate relations between predator and prey efficiently but other studies have shown that large carnivore faecal analysis also suggests dietary choice too. 3 However they too have bias due to lack of information on small prey species with further lack of data on whether the food was scavenged or hunted which can be indicated by direct observation.3

The analysis of food webs is complex; however within this context it has enabled the study of predator-prey relationships. In addition to indicating that the five predators have different diets but hunt similar sized prey due to different dietary niches. To conclude lions have the greatest impact on most prey species indicating that lions are the “Kings of Kruger”.

1. Mills, M.G.L. (1992) A comparison of method used to study food habits of large African carnivores. Wildlife 2001: population. Elsevier science. London

2. Owen-Smith,N. and Mills, M.G.L. (2008) Predator-prey size relationship in an African large-mammal food web. J. Anim. Ecol77, 173-183on of method used to study food habits of large African carnivores. Wildlife 2001: population. Elsevier science.London

3. Breuer, T. (2005) Diet choice of large carnivores in northern Cameroon. Afr. J. Ecol., 43, 97-106

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