TY - JOUR
T1 - Aggressive behaviour in immature captive Nile crocodiles, Crocodylus niloticus, in relation to feeding
AU - Morpurgo, B.
AU - Gvaryahu, G.
AU - Robinzon, B.
PY - 1993/6
Y1 - 1993/6
N2 - This study presents five aspects of aggressive behaviour in juveenile Nile crocodiles, Crocodylus niloticus, as observed in five cohorts of 6-18 month-old animals. During this period, the animals grew from a range of 35-55 cm, to a range of 65-115 cm. 1) Stock density related to aggression: decrease in density resulted in significant decrease in the frequency of agonistic events, with 0.64 events/100 crocodiles/min observed in a density of 6.7 crocodiles/m2, compared to 0.26 events/100 crocodiles/min observed in a density of 4.7 crocodiles/m2. 2) Aggression during feeding: in all five groups, there was a significantly higher level of aggression during feeding times. 3) Aggression related to body size: the largest crocodiles were the most aggressive group in agonistic events, mainly against the smallest ones. The largest group, the medium sized, was the least involved in agonistic events. 4) Aggression related to food preference: crocodile food preference was live fish > live chicks > dead fish > ground meat. Except for one food type (live chicks), a significant (p < 0.05) correlation was found between food preference and feeding related aggression in the prey diet groups. 5) Aggression related to an artificial selection for size: removal of the largest crocodiles (which formed 30% of the stock) from the population caused a dramatic decrease in all forms of aggressive behaviour.
AB - This study presents five aspects of aggressive behaviour in juveenile Nile crocodiles, Crocodylus niloticus, as observed in five cohorts of 6-18 month-old animals. During this period, the animals grew from a range of 35-55 cm, to a range of 65-115 cm. 1) Stock density related to aggression: decrease in density resulted in significant decrease in the frequency of agonistic events, with 0.64 events/100 crocodiles/min observed in a density of 6.7 crocodiles/m2, compared to 0.26 events/100 crocodiles/min observed in a density of 4.7 crocodiles/m2. 2) Aggression during feeding: in all five groups, there was a significantly higher level of aggression during feeding times. 3) Aggression related to body size: the largest crocodiles were the most aggressive group in agonistic events, mainly against the smallest ones. The largest group, the medium sized, was the least involved in agonistic events. 4) Aggression related to food preference: crocodile food preference was live fish > live chicks > dead fish > ground meat. Except for one food type (live chicks), a significant (p < 0.05) correlation was found between food preference and feeding related aggression in the prey diet groups. 5) Aggression related to an artificial selection for size: removal of the largest crocodiles (which formed 30% of the stock) from the population caused a dramatic decrease in all forms of aggressive behaviour.
KW - Aggression
KW - Crocodilia
KW - Feeding behavior
KW - Nile crocodile
UR - http://www.scopus.com/inward/record.url?scp=0027336060&partnerID=8YFLogxK
U2 - 10.1016/0031-9384(93)90373-N
DO - 10.1016/0031-9384(93)90373-N
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C2 - 8346299
AN - SCOPUS:0027336060
SN - 0031-9384
VL - 53
SP - 1157
EP - 1161
JO - Physiology and Behavior
JF - Physiology and Behavior
IS - 6
ER -