Thesis (MSc(Conservation Ecology and Entomology)--University of Stellenbosch, 2006. / The stomachs of 286 crocodiles (17 cm to 166 cm snout to vent length) were
lavaged over a two year period. Crocodylus niloticus has a similar ontogenetic shift
in diet to that of other crocodilians. Yearlings predated primarily on aquatic insecta
and arachnida, as crocodile size increased (juveniles) the diet became more diverse
including crustacea, amphibia and fish. The largest size class (sub-adults)
consumed primarily fish. Yearlings fed consistently throughout the year, however a
higher proportion of empty stomachs occurred within the juvenile and sub-adult
size classes during the winter months. A captive experiment with wild caught
crocodiles (0.7 kg - 20 kg) indicated a decrease in satiation rate (maximum mass of
food eaten as a percentage of crocodile body mass) from 11.3 % to 6.5 % with an
increase in crocodile size. Wild yearlings consumed 0.48 % of their body mass in
prey per day, and juveniles, 0.23 %. The wild food conversion rates of natural prey
were low, 32 % and 40 % for yearlings and juveniles respectively. This was
possibly due to a high percentage of indigestible (chitinous) invertebrate mass in
the diet. The percentage of stomach stone mass to crocodile body mass increased
with crocodile size. Seven species of nematodes were found within the stomachs,
four of which represent new geographic records.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2439 |
| Date | 12 1900 |
| Creators | Wallace, Kevin Michael |
| Contributors | Leslie, Alison J., University of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Stellenbosch |
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