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The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana

Thesis (MSc(Conservation Ecology and Entomology)--University of Stellenbosch, 2006.

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Bibliographic Details
Main Author: Wallace, Kevin Michael
Other Authors: Leslie, Alison J.
Format: Thesis
Language:English
Published: Stellenbosch : University of Stellenbosch 2008
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access_status_str Open Access
author Wallace, Kevin Michael
author2 Leslie, Alison J.
author_browse Leslie, Alison J.
Wallace, Kevin Michael
author_facet Leslie, Alison J.
Wallace, Kevin Michael
author_sort Wallace, Kevin Michael
collection Thesis
dc_rights_str_mv University of Stellenbosch
description Thesis (MSc(Conservation Ecology and Entomology)--University of Stellenbosch, 2006.
format Thesis
id oai:scholar.sun.ac.za:10019.1/2439
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:41:29.531Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2008
publishDateRange 2008
publishDateSort 2008
publisher Stellenbosch : University of Stellenbosch
publisherStr Stellenbosch : University of Stellenbosch
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/2439 The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana Wallace, Kevin Michael Leslie, Alison J. University of Stellenbosch. Faculty of Agrisciences. Dept. of Conservation Ecology and Entomology. Nile crocodile Feeding ecology Okavango Delta Digestion Dissertations -- Conservation ecology and entomology Theses -- Conservation ecology and entomology 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. Masters 2008-08-07T09:50:46Z 2010-06-01T08:48:46Z 2008-08-07T09:50:46Z 2010-06-01T08:48:46Z 2006-12 Thesis http://hdl.handle.net/10019.1/2439 en University of Stellenbosch application/pdf Stellenbosch : University of Stellenbosch
spellingShingle Nile crocodile
Feeding ecology
Okavango Delta
Digestion
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
Wallace, Kevin Michael
The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title_full The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title_fullStr The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title_full_unstemmed The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title_short The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana
title_sort feeding ecology of yearling juvenile and sub adult nile crocodiles crocodylus niloticus in the okavango delta botswana
topic Nile crocodile
Feeding ecology
Okavango Delta
Digestion
Dissertations -- Conservation ecology and entomology
Theses -- Conservation ecology and entomology
url http://hdl.handle.net/10019.1/2439
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AT wallacekevinmichael feedingecologyofyearlingjuvenileandsubadultnilecrocodilescrocodylusniloticusintheokavangodeltabotswana