Nest predation and maternal care in the Nile crocodile (Crocodylus niloticus) at Lake St Lucia, South Africa.
Information regarding nest predation, nest abandonment, and maternal care in the Nile crocodile (Crocodylus niloticus) is largely restricted to anecdotal observations, and has not been studied quantitatively. Consequently, we investigated their nesting biology using camera-traps over four years at Lake St Lucia, South Africa. We obtained 4305 photographs (daylight captures=90.1%, nocturnal=9.9%) of 19 nest-guarding females. Of 19 monitored nests, 37% were raided by predators (mean=12.1±6.2days subsequent to camera placement). All females returned to their nests following first predation, and on average returned three times between predator raids before nest abandonment. Water monitors (Varanus niloticus) and marsh mongoose (Atilax paludinosus) were the main egg predators. Nesting raids lasted 5.9±1.6days. Diurnally females were seldom on the nest, except during cool/cloudy weather or rain, preferring to guard from nearby shade. Females defended nests aggressively against non-human intruders. Five Nile crocodile females were observed liberating their hatchlings from nests. A detailed sequence of a mother excavating and transporting hatchlings revealed 13 excursions between nest and water over 32.5h. This, after months of continual nest attendance and defence, is illustrative of the high level of maternal care in Nile crocodiles. Camera-trapping is an effective, non-invasive method for further crocodile nesting behaviour research.
School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa. Electronic address: xandercombrink@gmail.com.
Xander
X
Combrink
School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa. Electronic address: jonathan.k.warner@gmail.com.
Jonathan K
JK
Warner
School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa. Electronic address: downs@ukzn.ac.za.
Colleen T
CT
Downs
D000489:Alligators and Crocodiles / Q000502:physiology*; D000818:Animals; D005260:Female; D008425:Maternal Behavior / Q000502:physiology*; D009425:Nesting Behavior / Q000502:physiology*; D011235:Predatory Behavior / Q000502:physiology*; D013019:South Africa
Camera traps; Maternal care; Nest guarding; Nest liberation; Nest predation; Nesting biology; Nile crocodile; Remote monitoring