Aggressive behaviour in immature captive Nile crocodiles, Crocodylus niloticus, in relation to feeding

B. Morpurgo*, G. Gvaryahu, B. Robinzon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)1157-1161
Number of pages5
JournalPhysiology and Behavior
Volume53
Issue number6
DOIs
StatePublished - Jun 1993

Keywords

  • Aggression
  • Crocodilia
  • Feeding behavior
  • Nile crocodile

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