Ostrich cf warthog
Sexless means for body composition of ostrich cf warthog. All values of mass are percentages of body mass.
Body mass 111.0 kg 70.7 kg
Dressing percentage 54.2% 52.3%
Head 0.615% 11.605%
Feet 3.8% 1.51%
Hide 5.713% 5.291%
Heart 0.865% 0.379%
Lungs and trachea 1.855% 0.869%
Spleen 0.053% 0.200%
Liver 1.478% 1.353%
Total gastrointestinal tract, empty 8.027% 3.40%
Stomach, empty 3.31% 0.534%
Stomach contents 3.06% 1.007%
Small intestine, empty 1.351% 0.776%
Small intestine contents 1.613% 1.617%
Small intestine length 8.82 m 10.207 m
Caecum length (paired in ostrich) 0.95 m 0.214 m
Large intestine including caecum, empty 2.86% 2.00%
Large intestine including caecum, contents 9.78%(needs checking) 10.3%
Large intestine including caecum, length 11.8 m 7.215 m
Total ingesta 13.94% 12.94%
Comments
Cumming D H M (1975) A field study of the ecology and behaviour of warthog. National Museums and Monuments of Rhodesia, Museum Memoir no. 7. 179 spp.
https://www.researchgate.net/figure/Location-of-Sengwa-Wildlife-Research-Area-SWRA-in-north-western-Zimbabwe-and-a-detailed_fig1_271187194
Scrutiny of his Table 4 suggests that ostrich scarce everywhere there are >2 individuals of warthog per square km
Sengwa Wildlife Research area (650 mm mean annual rainfall) is an example of an area lacking the ostrich, in which miombo occurs, and the ungulate community of body mass 15-300 kg is dominated by impala (74%), contains both roan and sable, numerous concentrate-selectors including two tragelaphins, plus two reduncins. Just the kind of community the ostrich seems to avoid.
Notably, warthog is very common here (12.4% of spp. 15-300 kg). I suspect that ostrich exits where warthog exceeds 5% of the community of ungulates (15-300 kg) + ostrich.
Ostrich avoids moisture (reduncins), dystrophy (hippotragins), and density (tragelaphins).
I suspect that abundance of warthog here is partly owing to absence of wildebeest.
zebra about 100
warthog 1000
reedbuck 150
waterbuck 175
bushbuck 'numerous' (say 100)
impala 6000
roan 10
sable 75
kudu 450
duiker and grysbok omitted though numerous
Total 8060
Area 373 square km
Also see https://faolex.fao.org/docs/pdf/zim224998.pdf
https://www.researchgate.net/publication/227775142_Changes_in_Miombo_woodland_cover_in_and_around_Sengwa_Wildlife_Research_Area_Zimbabwe_in_relation_to_elephants_and_fire
Richard Liversidge (https://en.wikipedia.org/wiki/Richard_Liversidge) told me the following on 23 March 1990:
The common warthog (Phacochoerus africanus) occurs, in a sparse but thriving population, on the De Beers estates in the area of Kimberley (https://en.wikipedia.org/wiki/Kimberley,_Northern_Cape).
This species was reintroduced (yes, re-) here about 1980. It now coexists here with the ostrich (Struthio camelus), under mean annual rainfall 450-500 mm.
The common warthog drops out in country drier than this, whereas the ostrich remains common, probably forming a progressively greater % of the community of herbivores into the extreme desert. The common warthog is virtually absent from the Kalahari Gemsbok National Park, and Smithers' records in the Kalahari proper refer only to wet years.
The common warthog becomes more common in wetter conditions, whereas the ostrich wanes to nil in the miombo biome.
The ostrich (me: mobile, sparse, wide-ranging) is nowhere particularly abundant relative to ungulates.
My experience on Wildlife Ranching and Research (mean annual rainfall about 500 mm) was that the ostrich was as common as it gets anywhere, and the common warthog sparse. One grade wetter (Nairobi National Park), the common warthog is commoner, and the ostrich presumably sparser. One grade wetter again (Nakuru National Park), and the common warthog is moderately common whereas the ostrich is virtually absent. It seems that where the waterbuck (Kobus ellipsiprymnus/defassa) occurs, the common warthog is common and the ostrich absent.
As I see it, there is ecological overlap between the ostrich and the common warthog, but a) most of their habitats are mutually exclusive, b) they have different diets, the ostrich targeting the grass heads and the common warthog going for the grass bases. No doubt they compete for forbs and insects (and feces?) to some extent.
So, they separate out by a) food quality (richer for the common warthog), b) habitat (wetter and with denser vegetation in common warthog), and c) plant parts (common warthog lower to the ground, and below ground-level).
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