Dietary biology of the Nile crocodile

The type and size of the prey depends mostly on the size of the crocodile.{{cite journal|author=Hutton, J. M. |title=Growth and feeding ecology of the Nile crocodile Crocodylus niloticus at Ngezi, Zimbabwe|journal=The Journal of Animal Ecology|volume=56|issue=1|pages=25–38|doi=10.2307/4797|jstor=4797|year=1987|bibcode=1987JAnEc..56...25H }} The diet of young crocodiles is made up largely of insects and other invertebrates, since this is the only prey the same animals can easily take. More than 100 species and genera of insects were identified among the food of crocodiles of this age. Of the insects taken there, beetles made up 58% of the diet, including Hydrophilus and Cybister. Giant water bugs but also crickets and dragonflies. Arachnids such as Dolomedes water spiders are taken, but always secondarily to insects in Uganda and Zambia.

Crabs are also largely taken by crocodiles under {{convert|1.5|m|ftin|0|abbr=on}}, especially the genus Potamonautes, with different species being the primary crustacean food in different areas. Mollusks may occasionally be taken by young crocodiles (they are taken in larger numbers later in life in parts of Uganda and Zambia).{{cite journal |author=Cott, H.B. |year=1961 |title=Scientific results of an inquiry into the ecology and economic status of the Nile crocodile (Crocodilus niloticus) in Uganda and Northern Rhodesia |journal=The Transactions of the Zoological Society of London |volume=29 |issue=4|pages=211–356 |doi=10.1111/j.1096-3642.1961.tb00220.x}} In the Okavango Delta, Botswana, the diet was similar but young crocodiles ate a broader range of insects and invertebrates, with beetles taken in similar numbers to other, similar prey, both aquatic and terrestrial. In Botswana, arachnids were more often found in young crocodiles than in Uganda and Zambia.{{cite journal|author=Wallace, K. M.|author2=Leslie, A. J.|name-list-style=amp |title=Diet of the Nile crocodile (Crocodylus niloticus) in the Okavango Delta, Botswana|journal=Journal of Herpetology|volume=42|issue=2|pages=361|doi=10.1670/07-1071.1|year=2008|s2cid=46987629}} In Zimbabwe, the dietary composition was broadly similar to that in other areas. However, in the Ugandan portion of Lake Victoria, true bugs and dragonflies both seem to outnumber beetles notably and up to a length of {{convert|1|to|2|m|ftin|0|abbr=on}} crocodiles had stomach contents that were made up 70–75% of insects.{{cite journal |author=Corbet, P.S. |date=1960 |title=The food of a sample of crocodiles (Crocodylus niloticus) from Lake Victoria |journal=Proceedings of the Zoological Society of London |volume=133 |issue=4 |pages=561–572|doi=10.1111/j.1469-7998.1960.tb05579.x }}{{cite journal|author=Corbet, P. S. |title=Notes on the insect food of the Nile crocodile in Uganda |journal=Proceedings of the Royal Entomological Society of London A |volume=34|issue=1–3 |pages=17–22 |doi=10.1111/j.1365-3032.1959.tb00223.x |year=2009}}

After Nile crocodiles reach {{convert|2|m|ftin|0|abbr=on}}, the significance of most invertebrates in the diet decreases precipitously. An exception to this is in Uganda and Zambia, where subadults and adults of even large sizes, up to {{convert|3.84|m|ftin|0|abbr=on}}, may eat very large numbers of snails. Nearly 70% of the crocodiles examined by Cott (1961) had some remains of snails inside their stomachs. Predation on amuplariid water snails was especially heavy in Bangweulu Swamp, Lake Mweru Wantipa, and the Kafue Flats, where mollusks representing 89.1, 87, and 84.7% of all prey in these locations, respectively. Gastropoda (4126 records per Cott) were taken much more than Lamellibranchiata (six records). Notable favorites include Pila ovata, which lives just under water on rocky surfaces (mainly found in crocodiles from Uganda) and Lanistes ovum, which is found submerged among water plants and on detritus (mainly from stomachs in Zambia).

File:Nile Crocodile (Crocodylus niloticus) trying to swallow a big Tilapia (Oreochromis sp.)... (16647120860).jpg as its prey]]

During the time from when they are roughly {{convert|1.5|to|2.2|m|ftin|0|abbr=on}} long (roughly 5 to 9 years old), Nile crocodiles seem to have the broadest diet of any age range. They take more or less much the same small prey as smaller crocodiles, including insects and arachnids, but also take many small to medium-sized vertebrates and quickly become capable taking down prey up to their own weight. Fish become especially significant around this age and size. However, Cott (1961) found that the only size range where fish were numerically dominant over other types of food was from {{convert|2|to|3.05|m|ftin|0|abbr=on}}. This size range consists of subadult males and a mixture of subadult and adult females. In Lake Turkana, fish were the only food in the stomachs of 45.4% of the crocodiles that did not have empty stomachs, in total 87.8% of the crocodiles that did not have empty stomachs there had fish in their stomachs. Graham (1968) noted that throughout East Africa, crocodile diets are driven by the regional availability of prey. The arid land surrounding Lake Turkana is a relatively barren region for diverse or numerous prey other than fish, so fish are an exceptionally important food source to crocodiles there.Graham, A., & Beard, P. (1973). Eyelids of Morning. A. & W. Visual Library, Greenwich, CT, 113.> In Lake Kyoga and Lake Kwana, 73.1% of the crocodiles that did not have empty stomachs had fish in their stomachs.{{cite journal|author=Hippel, E. V. |year=1946|title=Stomach contents of crocodiles|journal=The Uganda Journal|volume= 10|pages= 148–149}} At Lake St. Lucia in South Africa, many Nile crocodile congregate to feed on striped mullet (Mugil cephalus) as they make their seaward migration for spawning. Here, the crocodiles may line up in dozens across narrow straits of the estuary to effectively force the mullet into easy striking distance, with no observed in-fighting among these crocodile feeding congregations. At this time of plenty (before irrigation operations by humans led St. Lucia to have dangerously high saline levels), a {{convert|2.5|m|ftin|0|abbr=on}} crocodile could expect to eat {{convert|1.1|kg|lb|abbr=on}} of mullet daily, an exceptionally large daily amount for a crocodile.{{cite journal|author=Whitfield, A.K.|author2=Blaber, S.J.|name-list-style=amp |title= Predation on striped mullet (Mugil cephalus) by Crocodylus niloticus at St. Lucia, South Africa|journal= Copeia|volume= 1979|issue= 2|pages= 266|doi=10.2307/1443412|jstor=1443412 |year=1979}}

Larger fish, like catfish and freshwater bass, are preferred by adults more than {{convert|2.2|m|ftin|0|abbr=on}} in length. Particularly small fish are likely to be eaten only in case of sudden encounter, mostly in shallow, dry-season ponds where not much effort is needed to catch the small, agile prey.Stevenson-Hamilton, J. (1954). Wild life in South Africa. Cassell and Co., London. Most observed fishing by crocodiles takes place in waters less than {{convert|1.5|m|ftin|0|abbr=on}} deep and fish are often caught when they swim into contact with the crocodile's head, even literally right into the reptile's mouth. Across much of their range, they take any fish they encounter, but largish and relatively sluggish mesopredator fish such as lungfish and Barbus carp seem to be most widely reported. Many other genera are taken widely and relatively regularly, including Tilapia (which was the most significant prey genus in Lake Turkana), Clarias, Haplochromis, and Mormyrus.{{cite journal|author=Cott, H. B. |year=1954|title= The status of the Nile crocodile in Uganda|journal=Uganda Journal|volume=18|issue=1|pages= 1–13}} In Uganda and Zambia, lungfish comprised nearly two-thirds of the piscivorian diet for crocodiles. Similarly, in Lake Baringo, the lungfish is the crocodile's main prey and the crocodile is the lungfish's primary predator.{{cite journal|author=Mlewa, C. M.|author2=Green, J. M.|name-list-style=amp |title=Biology of the marbled lungfish, Protopterus aethiopicus Heckel, in Lake Baringo, Kenya|journal=African Journal of Ecology |volume=42 |issue=4 |pages=338|doi=10.1111/j.1365-2028.2004.00536.x|year=2004|bibcode=2004AfJEc..42..338M }} In the Okavango Delta, the African pikes (Hepsetus spp.) were the leading prey group for subadults, comprising more than a fourth of the diet.Wallace, K. M. (2006). [http://scholar.sun.ac.za/handle/10019.1/2439 The feeding ecology of yearling, juvenile and sub-adult Nile crocodiles, Crocodylus niloticus, in the Okavango Delta, Botswana]. Doctoral dissertation. University of Stellenbosch. Extremely large fish, such as Nile perch (Lates niloticus), goliath tigerfish (Hydrocynus goliath), and even sharks, are taken on occasion, in addition to big catfish, such as Bagrus spp. and Clarias gariepinus, which are preyed upon quite regularly in areas where they are common. In the Zambezi River and Lake St. Lucia, Nile crocodiles have been known to prey on bull sharks (Carcharhinus leucas) and sand tiger sharks (Carcharias taurus).{{Cite web|title = FLMNH Ichthyology Department: Bull Shark|url = http://www.flmnh.ufl.edu/fish/gallery/descript/bullshark/bullshark.htm|website = www.flmnh.ufl.edu|access-date = 23 October 2015}}{{Cite book|title = Ecology and Conservation of Estuarine Ecosystems: Lake St Lucia as a Global Model|url = https://books.google.com/books?id=QxEgAwAAQBAJ|publisher = Cambridge University Press|date = 16 May 2013|isbn = 9781107354999|first1 = Renzo|last1 = Perissinotto|first2 = Derek D.|last2 = Stretch|first3 = Ricky H.|last3 = Taylor}}{{Cite web|title = Deadly bull shark is a magnificent, hunted creature {{!}} Florida Weekly|url = http://charlotte.floridaweekly.com/news/2010-06-24/Outdoors/Deadly_bull_shark_is_a_magnificent_hunted_creature.html|website = charlotte.floridaweekly.com|access-date = 23 October 2015}} The largest fishes attacked in such cases may potentially weigh more than {{convert|45|kg|lb|abbr=on}}.Pienaar, U. (1968). The Freshwater Fishes of the Kruger National Park. Republic of South Africa: The National Parks Board of Trustees of the Republic of South Africa.Skelton, P. (1993). A Complete Guide to the Freshwater Fishes of Southern Africa. Halfway House: Southern Book Publishers Ltd.

When capturing large fish, they often drag the fish onto shore and swing their heads around to smash the fish onto the ground until it is dead or incapacitated. More modestly sized fish are generally swallowed whole. The Nile crocodile has a reputation as a voracious and destructive feeder on freshwater fish, many of which are essential to the livelihoods of local fisherman and the industry of sport fishing. However, this is very much an unearned reputation. As cold-blooded creatures, Nile crocodiles need to eat far less compared to an equivalent-weighted warm-blooded animal. The crocodile of {{convert|2|to|3.05|m|ftin|0|abbr=on}} consumes an average {{convert|286|g|oz|abbr=on}} of fish per day. In comparison, piscivorous water birds from Africa eat far more per day despite being a fraction of the body size of a crocodile; for example, a cormorant eats up to {{convert|1.4|kg|lb|abbr=on}} per day (about 70% of its own body weight), while a pelican consumes up to {{convert|3.1|kg|lb|abbr=on}} per day (about 35% of its own weight). The taking of commercially important fish, such as Tilapia, has been mentioned as a source of conflict between humans and crocodiles, and used as justification for crocodile-culling operations; however, even a primarily piscivorous crocodile needs relatively so little fish that it cannot deplete fish populations on its own without other (often anthropogenic) influences.{{cite journal|author=Gans, C.|author2=Pooley, A. C.|name-list-style=amp |title=Research on Crocodiles? |journal=Ecology |volume=57 |issue=5 |pages=839|doi=10.2307/1941051|jstor=1941051|year=1976|bibcode=1976Ecol...57..839G }} Additionally, crocodiles readily take dead or dying fish given the opportunity, thus are likely to incidentally improve the health of some fish species' populations as this lessens their exposure to diseases and infection.

File:Djerba Explore Nile Crocodiles eating 02.JPG

Frogs are regionally significant prey for small, young crocodiles in many regions, mainly those in the {{convert|0.5|to|1.5|m|ftin|0|abbr=on}} size range. The main amphibian prey species from Uganda and Zambia was the African common toad (Amietophrynus regularis) while in Botswana, the main amphibian prey was the reed frog (Hyperolius viridiflavus). Even the largest frog in the world, the goliath frog (Conraua goliath), has reportedly been preyed on by young Nile crocodiles.Thomson, G. (2006). Goliath Frog (Conraua goliath). B Freedman, ed. Encyclopedia of Endangered Species, Vol. 1.

In general, reptiles become relatively common only in the diet in larger juvenile specimens and subadults. Large reptiles, or armoured reptiles such as turtles, were almost negligible in crocodiles under {{convert|2.5|m|ftin|0|abbr=on}} and most common in the stomachs of crocodiles over {{convert|3.5|m|ftin|0|abbr=on}} in length from Uganda and Zambia. Small species of reptiles are largely ignored as prey at this size. Freshwater turtles are often the most frequently recorded reptilian prey, unsurprisingly perhaps because most other reptiles other than a small handful of Lycodonomorphus water snakes are more terrestrial than water-based.

In a study, the serrated hinged terrapin (Pelusios sinuatus) (also sometimes referred to as the "water tortoise") was more commonly reported in the stomach contents of adult crocodiles from Kruger National Park than any single mammal species.{{cite journal|author=Pienaar, U. D. V. |title= Predator-prey relationships amongst the larger mammals of the Kruger National Park|journal= Koedoe|volume= 12|doi=10.4102/koedoe.v12i1.753|year= 1969|doi-access= free}} Other turtle species commonly recorded among Nile crocodile prey include the Speke's hinge-back tortoise (Kinixys spekii) and East African black mud turtle (Pelusios subniger). Beyond their ready availability and respectable size, turtles are favored by big crocodiles due to their slowness, which allows the cumbersome crocodiles to capture them more easily than swifter vertebrates.{{cite journal|author=Hailey, A. |title=Low survival rate and high predation in the African hingeback tortoise Kinixys spekii|journal=African Journal of Ecology|volume=39|issue=4|pages=383–392|doi=10.1046/j.0141-6707.2001.00328.x|year=2001|bibcode=2001AfJEc..39..383C }}{{cite journal|author=Caro, T. |author-link=Tim Caro|author2=Shaffer, H. B.|name-list-style=amp |title= Chelonian antipredator strategies: preliminary and comparative data from Tanzanian Pelusios|journal= Chelonian Conservation and Biology|volume= 9|issue= 2|pages= 302|doi=10.2744/CCB-0812.1|year= 2010|s2cid=17057901}} While adults have a sufficient bite force to crush turtle shells, younger crocodiles sometimes are overly ambitious, and will choke to death attempting to swallow whole large river turtles.Alderton, D. (1998). Crocodiles & alligators of the world. Cassell Illustrated, 978-0713723823.Storrs G. W. (2003). "Late Miocene-early Pliocene crocodilian fauna of Lothagam, Southwest Turkana basin, Kenya", in Leakey M. G. & Harris J. M. (eds), Lothagam: the Dawn of Humanity in Eastern Africa. Columbia University Press, New York. {{ISBN|0-231-11870-8}} pp. 137–159. A variety of snakes has been preyed on from relatively small, innocuous species such as the common egg-eating snake (Dasypeltis scabra) to the largest African snakes species, the African rock python (Python sebae), which can exceed {{convert|6.1|m|ftin|0|abbr=on}} in length and weigh over {{convert|91|kg|lb|abbr=on}}. Venomous species, including the puff adder (Bitis arietans), the forest cobra (Naja melanoleuca), and the black mamba (Dendroaspis polylepis) have been recorded as Nile crocodile prey. The only frequently recorded lizard prey is the large Nile monitor (Varanus niloticus), although this mesopredator may be eaten fairly regularly, as they often share similar habitat preferences, whenever a crocodile is able to ambush the stealthy monitor, which is more agile on land than the bulkier crocodile.

File:NileCrocodile--Etiopia-Omo-River-Valley-01.jpgs have little to fear from crocodiles on land, but they can be vulnerable while swimming to crocodiles lurking under water.]]

Numerous birds, including storks, small wading birds, waterfowl, eagles, and even small, swift-flying birds, may be snatched. As a whole, birds are quite secondary prey, rarely comprising more than 10–15% of crocodiles' diets, although are taken fairly evenly across all crocodile size ranges, excluding juveniles less than {{convert|1|m|ftin|0|abbr=on}}.{{cite journal|author1=Pooley, A. C. |author2=Gans, C. |title= The Nile crocodile|journal= Scientific American|volume= 234|issue= 4|pages= 114–119, 122–124 |pmid=1257732|year= 1976|doi=10.1038/scientificamerican0476-114|bibcode=1976SciAm.234d.114P}} Birds most often taken are African darters (Anhinga rufa) and reed (Microcarbo africanus) and white-breasted cormorants (Phalacrocorax lucidus), followed by various waterfowl, including most breeding geese and ducks in Africa. Slow-swimming pelicans are also vulnerable to crocodiles.{{cite book |title=Crocodiles and Alligators |editor1-last=Ross |editor1-first=Charles A |editor2-last=Garnett |editor2-first=Stephen |publisher=Checkmark Books |year=1989 |isbn=978-0816021741 |url-access=registration |url=https://archive.org/details/crocodilesalliga0000unse}} Nile crocodiles apparently frequently station themselves underneath breeding colonies of darters, cormorants, herons, egrets, and stork and presumably snatch up fledgling birds as they drop to the water before they can competently escape the saurian, as has been recorded with several other crocodilians.

Wading birds, even large and relatively slow-moving types such as the goliath heron (Ardea goliath), tend to be highly cautious in avoiding deep water in crocodile-occupied wetlands, whereas cormorants and waterfowl forage over deeper water and are easier for crocodiles to ambush, with Egyptian geese (Alopochen aegyptiaca) and spur-winged geese (Plectropterus gambensis) recorded as being taken largely while flightless due to molting their flight feathers.{{cite journal|author=McKinney, F.|author2=Buitron, D.|author3=Derrickson, S. R.|name-list-style=amp |year=1990|title= Persistent quacking in dabbling ducks: a predator-luring signal? |url=http://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/839|journal=Wildfowl|volume=41|issue=41|pages= 92–98}}{{cite journal|author=Pitman, C. C. |year=1965|title= The nesting and some other habits of Alopochen, Nettapus, Plectropterus and Sarkidiornis|journal=Wildfowl|volume=16|issue=16|pages= 7|url=http://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/288}}{{cite journal|author=Mock, D. W.|author2=Mock, K. C.|name-list-style=amp |year=1980|title=Feeding behavior and ecology of the Goliath Heron|journal= The Auk|pages= 433–448|volume=97|issue=3|jstor=4085837 |url=https://sora.unm.edu/node/23426}}{{cite journal|author=Petri, S. |year=1998|title=Molt patterns of nonbreeding white-faced whistling-ducks in South Africa|url=https://sora.unm.edu/sites/default/files/journals/auk/v115n03/p0774-p0780.pdf|journal= The Auk|volume= 115|issue=3|pages= 774–780|jstor=4089428|doi=10.2307/4089427 |hdl=1808/16595|hdl-access=free}}Todd, F.S. ed. (1996). Natural History of the Waterfowl. San Diego Natural History Museum, San Diego, California and Ibis Publishing Company. {{ISBN|0-934797-11-0}}. In one case, a crocodile was filmed capturing a striated heron (Butorides striata) in mid-flight.{{cite web |url=https://www.youtube.com/watch?v=Hk2pGJNIpL8 |title=Crocodile snaps heron from air |date=11 January 2011 |publisher=YouTube.com |access-date=1 January 2015}} Ospreys (Pandion haliaetus) are known to be grabbed while they dive for fishPoole, Alan F., Rob O. Bierregaard and Mark S. Martell. (2002). Osprey (Pandion haliaetus). The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. as are possibly African fish eagles (Haliaeetus vocifer), while crowned eagles (Stephanoaetus coronatus) have reportedly been ambushed on land at carrion.{{cite web |url=http://www.africanraptors.org/simon-thomsett-on-the-african-crowned-eagle-part-2/ |title=Simon Thomsett on the African Crowned Eagle |author=Simon Thomsett |date=6 June 2011 |publisher=African Raptors |access-date=1 January 2015}} Crocodiles are occasionally successful in grabbing passerines such as weaver birds, including the abundant red-billed quelea (Quelea quelea), and swallows, having been observed to breach the water and in a matter of seconds sweep off a branch full of birds with remarkable success.{{cite journal|author=Attwell, R. I. G. |title=Crocodiles feeding on weaver birds |journal=Ibis |volume=96 |issue=3 |pages=485–486 |year=2008 |doi=10.1111/j.1474-919X.1954.tb02342.x}}Thiollay, J. M. (1989). Natural predation on quelea. Quelea quelea. Africa's Bird Pest 216–229.Baker, S. W. (1891). Wild beasts and their ways: reminiscences of Europe, Asia, Africa and America. Macmillan and co. Larger land birds, such as bustards, guineafowl, ground hornbills (Bucorvus spp.) and ostriches (Struthio camelus), may be taken when they come to water to drink, but like most birds, are seldom harassed and a minor part of the diet.

Determining the percentage of any specific food item in a crocodile's diet is difficult because their defecation in water makes scat analysis impossible, and capturing individual animals to analyze their stomach contents is painstaking. In addition, as an animal that feeds rarely, sometimes only a few times in a year, even the individual stomach content examinations sometimes prove to be unsuccessful. However, as crocodiles grow, relying solely on small and agile food items such as fish becomes difficult, this causes a shift in the diet as the animal matures, for energy conservation purposes, as in other predators. Nonetheless, starting around {{convert|1.5|m|ftin|0|abbr=on}}, they can become capable mammalian hunters and their ability to overpower a wide range of mammals increases along with their size. Crocodiles less than {{convert|3|m|ftin|0|abbr=on}} may take a variety of medium–sized mammals up to equal their own mass, including various monkeys, duikers,{{cite book |author=Kingdon, J. |author2=Happold, D. |author3=Butynski, T. |author4=Hoffmann, M. |author5=Happold, M. |author6=Kalina, J. |name-list-style=amp |year=2013 |title=Mammals of Africa |volume=1 |publisher=A&C Black}} rodents, hares, pangolins, bats, dik-dik, suni (Neotragus moschatus),Schütze, H. (2002). Field Guide to the Mammals of the Kruger National Park. Struik. oribi (Ourebia ourebi){{cite journal|author=Tekalign, W.|author2=Bekele, A.|name-list-style=amp |url=http://www.ajol.info/index.php/sinet/article/view/78229|year=2011|title= Population Status, Foraging and Diurnal Activity Patterns of Oribi (Ourebia ourebi) in Senkele Swayne's Hartebeest Sanctuary, Ethiopia|journal=SINET: Ethiopian Journal of Science|volume=34|issue=1|pages= 29–38}} and other small ungulates up to the size of a Thomson's gazelle (Eudorcas thomsonii).

Rodents and shrews may enter the diet of juvenile crocodiles, i.e. {{convert|1.0|to|1.5|m|ftin|0|abbr=on}}, and become commonplace in subadult and small adult crocodiles. Species recorded include the Natal multimammate mouse (Mastomys natalensis), African marsh rat (Dasymys incomtus), common rufous-nosed rat (Oenomys hypoxanthus), and savanna swamp shrew (Crocidura longipes). In many areas, the cane rats are a particular favorite mammalian food for crocodiles, particularly the relatively large greater cane rat (Thryonomys swinderianus). In Uganda and Zambia, the latter species are the leading overall mammalian prey type for crocodiles and one Kenyan crocodile of {{convert|2.7|m|ftin|0|abbr=on}} in length had 40 greater cane rats in its stomach.Fonck, H. (1910). Deutsch-Ost-Afrika: eine Schilderung deutscher Tropen nach 10 Wanderjahren. Vossische. Berlin. Cape porcupines (Hystrix africaeaustralis) are known to have been preyed on several times in Kruger National Park, their quills apparently being an insufficient defense against the tough jaws and digestive systems of crocodiles.Grenard, S. (1991). Handbook of alligators and crocodiles. Malabar, FL: Krieger. Small carnivores are readily taken opportunistically, including both African clawless otters (Aonyx capensis){{cite journal|author=Larivière, S.|year=2001|title=Aonyx capensis|journal=Mammalian Species|volume=671|pages=1–6|url=http://www.science.smith.edu/msi/pdf/671_Aonyx_capensis.pdf|doi=10.1644/1545-1410(2001)671<0001:ac>2.0.co;2|s2cid=198968982|access-date=2021-12-19|archive-date=2015-09-19|archive-url=https://web.archive.org/web/20150919153420/http://www.science.smith.edu/msi/pdf/671_Aonyx_capensis.pdf|url-status=dead}} and spotted-necked otters (Hydrictis maculicollis), as well as water mongoose (Atilax paludinosus), African wildcats (Felis lybica) and servals (Leptailurus serval).{{cite journal|author=Geertsema, A. A. |year=1976|title= Impressions and observations of serval behavior in Tanzania, East Africa|journal=Mammalia|volume= 40 |pages=13–19 |doi=10.1515/mamm.1976.40.1.13 |s2cid=84461675}}

Adult Nile crocodiles, i.e. at least {{convert|3.05|m|ftin|0|abbr=on}}, are apex predators. While adults can and will consume nearly all types of prey consumed by the younger specimens, as adult crocodiles gain bulk, they lose much of the necessary maneuverability to capture agile prey such as fish and are not likely to meet their dietary needs by consuming small prey and may expel unnecessary amounts of energy, so take them secondarily to larger prey. Primates of various sizes may be taken by subadult or adult crocodiles. In some areas, some number of baboons are taken, such as in Okavango Delta, where chacma baboons (Papio ursinus) are eaten and Uganda, where olive baboons (Papio anubis) are taken.{{cite journal|author=Cheney, D. L.|author2=Seyfarth, R. M.|author3=Fischer, J.|author4=Beehner, J.|author5=Bergman, T.|author6=Johnson, S. E.|author7=Silk, J. B.|name-list-style=amp |title=Factors affecting reproduction and mortality among baboons in the Okavango Delta, Botswana|journal=International Journal of Primatology|volume=25|issue=2|pages=401|doi=10.1023/B:IJOP.0000019159.75573.13|url=http://www.rci.rutgers.edu/~palombit/Cheney_et_al_2004.pdf|year=2004|citeseerx=10.1.1.486.5396|s2cid=17070708}}{{cite journal|author=Rowell, T.E. |title=Forest living baboons in Uganda|journal=Journal of Zoology|volume=149|issue=3|pages=344–364|doi=10.1111/j.1469-7998.1966.tb04054.x|year=2009}} No records of them hunting apes (other than humans) have been made, but based on a strong reluctance to cross waters with crocodiles and a violent reaction to the visual stimuli of crocodiles, chimpanzees (Pan troglodytes) and gorillas (Gorilla beringei) are thought to consider Nile crocodiles a serious threat.{{cite journal|author=Klailova, M.|author2=Casanova, C.|author3=Henschel, P.|author4=Lee, P.|author5=Rovero, F.|author6=Todd, A.|name-list-style=amp |pmid=23363591|title= Non-human predator interactions with wild great apes in Africa and the use of camera traps to study their dynamics|journal=Folia Primatologica|volume=83|issue=3–6|pages=312–28|year=2012|doi=10.1159/000342143|s2cid=1759228}} Few details are known about the dietary habits of Nile crocodiles living in Madagascar, although they are considered potential predators of several lemur species.Small, E. (2013). Steven M. Goodman', Sheila O'Connor, and Olivier Langrand Field Museum of Natural History. Lemur Social Systems and Their Ecological Basis, 51.Goodman, S. M., O'Connor, S., & Langrand, O. (1993). "A review of predation on lemurs: implications for the evolution of social behavior in small, nocturnal primates", pp. 51–66 in Lemur social systems and their ecological basis. Springer US. Other nonungulate prey known to be attacked by Nile crocodiles includes aardvarks (Orycteropus afer)Knöthig, J. (2005). [http://www.tierseiten.com/roehrenzaehner/aardvark.pdf Biology of the Aardvark (Orycteropus afer)] {{webarchive|url=https://web.archive.org/web/20080414134457/http://www.tierseiten.com/roehrenzaehner/aardvark.pdf |date=14 April 2008 }}. Ruprecht-Karls-Universität, Heidelberg, Germany (MSc thesis). and African manatees (Trichechus senegalensis).Dodman, T., Dagou Diop, N.M. & Khady, S. (eds.). (2008). Conservation Strategy for the West African Manatee. UNEP, Nairobi, Kenya andWetlands International Africa, Dakar, Senegal.

File:Crocodile attack during Mara River crossing - frame 1 - Flickr - Lip Kee.jpg crossing the Mara River, attacked by crocodiles]]

Among the mammals, the bulk of the prey for adults are antelope. In particular, the genus Kobus is often among the most vulnerable because it forages primarily in wetland areas and seeks to evade more prolific mammalian predators (such as hyenas, lions, etc.) by traveling along waterways. In some cases in Kruger National Park, antelope have been driven into water while being pursued by packs of African wild dogs (Lycaon pictus), which hunt by endurance, engaging prey in a grueling chase until it is exhausted (a very successful hunting style), only to be killed by opportunistic crocodiles. While not as extensively aquatic as the genus Kobus, the reedbucks and the impala (Aepyceros melampus) have both shown a partiality for grasslands adjoining wetlands and riparian zones, so are also very commonly recorded prey items. In Kruger National Park, over the course of 22 years of discontinuous observation, 60% of the large-game kills observed as perpetrated by crocodiles consisted of impala, while more than 15% of observed kills were made up of waterbuck (Kobus ellipsiprymnus), the largest of the genus Kobus at more than {{convert|200|kg|lb|abbr=on}} in weight. Elsewhere, the waterbuck appears to be the most significant mammalian prey for large adult crocodiles, such as in Uganda and Zambia (although due to more sporadic general ungulate populations in those countries, ungulates are less common as prey than in some other countries), as well as in Hluhluwe–iMfolozi Park, South Africa.{{cite journal|author=Melton, D. A.|author2=Melton, C.|name-list-style=amp |doi=10.1111/j.1365-2028.1982.tb00279.x|title= Condition and mortality of waterbuck (Kobus ellipsiprymnus) in the Umfolozi Game Reserve|journal=African Journal of Ecology|volume=20|issue=2|pages=89|year=1982|bibcode=1982AfJEc..20...89M }} Other antelopes recorded as prey including gazelles, bushbuck (Tragelaphus scriptus), sitatunga (Tragelaphus spekii), kudu (Tragelaphus strepsiceros),{{cite journal|author=Cronje, H. P.|author2=Reilly, B. K.|author3=MacFadyen, I. D.|name-list-style=amp |title=Natural mortality {{sic|amou|ng|nolink=y}} four common ungulate species on Letaba Ranch, Limpopo Province, South Africa|journal=Koedoe|volume=45|doi=10.4102/koedoe.v45i1.12|year=2002|doi-access=free}} steenbok (Raphicerus campestris),Schaller, G. B. (2009). The Serengeti lion: a study of predator-prey relations. University of Chicago Press. eland (Taurotragus oryx), gemsbok (Oryx gazella),{{cite web |url= http://www.crocodilesoftheworld.co.uk/animals/crocodylus-niloticus.html |title=Nile Crocodile |publisher=Crocodiles of the World, Crocodile Conversation and Education Centre |access-date=1 January 2015}} sable (Hippotragus niger) and roan antelopes (Hippotragus equinus), up to a half dozen types of duiker, topi (Damaliscus lunatus),Anthony, S. B. (2011). [http://repository.sustech.edu/bitstream/handle/123456789/6585/The%20feed%20and%20...%20.pdf?sequence=1&isAllowed=y The feed and feeding Habits of Tiang (Damaliscus korrigrum) in the Sudd Region–Sudan] (Doctoral dissertation, Sudan University of Science and Technology). hartebeest (Alcelaphus buselaphus) and both species of wildebeest (Connochaetes sp.).{{cite journal|author=Mills, M. G. L. |author2=Biggs, H. C.|name-list-style=amp |year=1993|title= Prey apportionment and related ecological relationships between large carnivores in Kruger National Park |journal=Symposia of the Zoological Society of London|volume=65|pages= 253–268}}

Other ungulates are taken by Nile crocodile more or less opportunistically. These may include Grévy's (Equus grevyi)Moehlman, P. D. R. (2002). [http://www.equids.org/docs/Moehlman_02_Low.pdf Equids: zebras, asses, and horses: status survey and conservation action plan]. IUCN. and plains zebras (Equus quagga),Marshall Cavendish Corporation, 2004. Encyclopedia of the Aquatic World. New York: Marshall Cavendish. pygmy hippopotamus (Choeropsis liberiensis),Eltringham, S. K. (1999). The hippos: natural history and conservation. Princeton University Press. warthogs (Phacochoerus africanus), bushpigs (Potamochoerus larvatus) and red river hogs (Potamochoerus porcus). In Maasai Mara, Tanzania, large crocodiles congregate at river crossings used by migrating herds of Burchell's zebras and blue wildebeests (Connochaetes taurinus), picking off hundreds of these large ungulates annually.Kennedy, A. S., & Kennedy, V. (2013). [https://books.google.com/books?isbn=1400844916 Animals of the Masai Mara]. Princeton University Press. All domesticated ungulates and pet animals will on occasion be hunted by Nile crocodiles, up to the size of dromedary camels (Camelus dromedarius){{cite journal | author = Owen T. R. H. | year = 1951 | title = Notes on the feeding and other habits of the crocodile | journal = Sudan Wild Life and Sport | volume = 2 | issue = 2| pages = 33–5}} and cattle (Bos taurus){{cite journal|author=Aust, P.|author2=Boyle, B.|author3=Fergusson, R.|author4=Coulson, T.|name-list-style=amp|title=The impact of Nile crocodiles on rural livelihoods in northeastern Namibia|journal=South African Journal of Wildlife Research|volume=39|pages=57–69|doi=10.3957/056.039.0107|year=2009|s2cid=86595859}} In Tanzania, up to 54 head of cattle may be lost to crocodiles annually, increasing the human-crocodile conflict level. Goats (Capra hircus), donkeys (Equus asinus) and dogs (Canis familiaris) may also rank among the most regularly recorded domesticated animals to be taken by Nile crocodiles.{{cite journal |author=Baldus R.D. |year=2005 |title=Community in Tanzania to Harvest Problem Crocodiles |journal=African Indaba E-Newsletter |volume=3 |issue=3 |page=20}}

Particularly large adults, on occasion, take on even larger prey, such as giraffe (Giraffa sp.),{{cite web|url=http://www.philadelphiazoo.org/zoo/Meet-Our-Animals/Reptiles/Crocodiles-and-Alligators/Nile-crocodile.htm |title=Nile crocodile |publisher=Philadelphiazoo.org |date=25 July 2003 |access-date=25 April 2013}} Cape buffalo (Syncerus caffer), and young African bush elephants (Loxodonta africana).{{cite book |last=Macdonald |first=David |year=2001 |title=The new encyclopedia of mammals |publisher=Oxford University Press |isbn=9780198508236}}{{cite web|url=http://www.switcheroozoo.com/profiles/africanelephant.htm |title=African Elephant – Animal Facts |publisher=Switcheroozoo.com |access-date=25 April 2013}} Even heavier prey, such as black rhinoceros (Diceros bicornis), have been killed by crocodiles. In one case in the Tana River of Kenya, as observed by Max Fleishmann (communicated via letter to Theodore Roosevelt), a Nile crocodile was able to bring down one of these huge herbivores by the help of muddy bank terrain, the adult female rhino's poor decision to enter deeper water rather than retreat to land and finally having been joined in drowning the animal by one to two other crocodiles.Selous, F. C. (1908). African nature notes and reminiscences. Galago. An additional case of predation on an adult black rhino was reportedly observed in northern Zambia. A bull giraffe that lost his footing on a river bank in Kruger National Park was seen to be killed by a large crocodile, while in another case there, a healthy bull buffalo was seen to be overpowered and killed by an average-sized adult male crocodile measuring {{convert|4.25|m|ftin|0|abbr=on}} after a massive struggle, an incident less commonly seen at this size. Since crocodiles are solitary hunters, the Nile crocodile is the only predator in Africa known to attack full-grown Cape buffaloes alone, compared to the preferred pride attack method of lions.Notling, M. (2013) African Safari Journal and Field Guide. Global Travel Publishers, {{ISBN|093989517X}}.

Although Nile crocodiles occasionally prey on hippo calves, even large adult crocodiles rarely attack them because of the aggressive defense by mother hippos and the close protection of the herd, which pose a serious threat. Hippo calves have been observed to at times act brazenly around crocodiles, foraging without apparent concern and even bumping into the reptiles. However, some large Nile crocodiles have been recorded as predators of subadult hippos; anecdotally, the infamous giant crocodile Gustave was reported to have been seen killing adult female hippos.Quammen, D. (2004). Monster of God: the man-eating predator in the jungles of history and the mind. WW Norton & Company. A {{convert|5|m|ftin|0|adj=mid|abbr=on}} specimen from Zambia was found to have eaten a "half-grown hippo". At the no-longer-existent Ripon Falls in Uganda, one adult bull hippo was seen to be badly injured in a mating battle with a rival bull hippo, and was then subsequently attacked by several crocodiles, causing it to retreat to a reedbed. When the male hippo returned to the water, it was drowned and killed by the group of Nile crocodiles amid "a truly terrifying commotion". However, other than rare instances, adults of megafauna species such as hippopotamuses, rhinoceroses, and elephants are not regular prey and are not typically attacked, with the exception of giraffes, since their anatomy makes them vulnerable to attack while taking a drink.

Nile crocodiles occasionally prey on big cats including lions and leopards.Bailey, T. N. (1993). The African leopard: ecology and behavior of a solitary felid. Columbia University Press. However, in order to save energy, crocodiles do not prefer such agile animals, as most attacks will end before they can strike. Thus they usually attack agile prey in the absence of regular prey items. Other large carnivores that dwell in Africa near the top of the food chain can also on occasion fall prey to crocodiles. Such predators that can find themselves victim to crocodiles include hyenas (3 out of 4 species reported as prey for Nile crocodiles, only the desert-dwelling brown (Parahyaena brunnea) being excluded),Brottman, M. (2013). Hyena. Reaktion Books. African wild dogs, jackals, and cheetahs (Acinonyx jubatus).

In the Nile crocodile as well as in at least 13 other species of crocodilian, a variety of fruit (mostly fleshy) has been found in stomach content. While these are probably sometimes used as gastroliths, they are likely often ingested for their nutritional value. Based on these findings, it has also been suggested that crocodiles may act as seed dispersers.{{cite journal|first1=S. G. |last1=Platt|first2=R. M.|last2=Elsey|first3=H.|last3=Liu|first4=T. R.|last4=Rainwater|first5=J. C.|last5=Nifong|first6=A. E.|last6=Rosenblatt|first7=M. R.|last7=Heithaus|first8=F. J.|last8=Mazzotti|title=Frugivory and seed dispersal by crocodilians: an overlooked form of saurochory? |journal=Journal of Zoology |volume=291|issue=2|pages=87–99|year=2013|doi=10.1111/jzo.12052|doi-access=free}}

{{reflist}}

Category:Crocodylidae

Category:Eating behaviors

Category:Predation