There is something about a large crocodile that captures your attention every single time. A couple of mornings ago, while exploring the banks of the Sand River, I witnessed one of the biggest crocodiles I have ever seen throw itself out of the water and onto a sandbank. This beast was totally unbothered by our presence. As we sat watching him, a question came from the back of the vehicle, “How do crocodiles give birth?” A very good and thought-provoking question that sent my mind into thinking that in all my years guiding at Londolozi, witnessing a female crocodile nesting remains one of those experiences that has never presented itself. And the more the winter approaches, the possibilities increase.
Mating Crocodiles
Most people associate new life with summer. The rains, the vibrant bush, the baby impala on wobbly legs. And while that is all very much true at Londolozi, not everything follows that rule. As the winter months begin to show themselves on the horizon and the Sand River slowly recedes, exposing the sandy banks along its edges, female Nile Crocodiles are quietly preparing to do something extraordinary that almost nobody ever sees.
Finding an adequate den.
After mating, a female crocodile’s entire focus shifts to finding the perfect nest site. This is where she becomes almost impossible to observe. Female crocodiles are extraordinarily secretive, deliberately seeking out tucked-away, elevated banks that offer the right combination of warmth, drainage and concealment. They do not nest in the open. They choose spots hidden behind reeds, beneath overhanging vegetation, or wedged against the base of an embankment where predators are unlikely to stumble upon them.
The thought of finding a female in that moment, excavating a hole with her hind legs, is something I will always think about every time the Sand River banks come into view on a winter morning. Once satisfied with her chosen site, she will deposit a clutch of around 50 eggs before carefully covering them with sand and settling into a long and vigilant wait.
What makes the nesting even more remarkable is that the sex of the hatchlings will be determined entirely by the temperature of the sand around them. Nests sitting between 31 and 34 degrees Celsius tend to produce males, while cooler temperatures around 26 to 30 degrees produce females. By simply choosing where to dig, the female is shaping the outcome of her offspring in a way that feels almost deliberate. The incubation period stretches between 80 and 90 days, during which she rarely strays far, seeing off anything that comes too close with an aggression that catches most people off guard.
If witnessing the nesting would be special, what comes at the end of that 90-day wait is the stuff of bucket lists. As the hatchlings begin to call from within the eggs, a soft, high-pitched sound kicks the mother into excavating the nest. She then does something that goes against all our assumptions about crocodiles: she gently picks up her hatchlings in the same jaws capable of crushing bone and carefully carries them down to the water. A massive crocodile delicately carrying her young to the Sand River is something I have never heard of people witnessing here at Londolozi. It is easy to understand why it remains so elusive.
The coming weeks will have the Sand River banks under close watch. It is out there somewhere, happening quietly while we drive past. It is just a matter of being in the right place at the right time. Crossing fingers.
I’ve always thought it was so interesting that like most reptiles, crocodiles and alligators guard their nests. I once rode by an alligator nest in the Everglades on a tram, and that mother was not happy that we were driving by so closely. It made me glad to be elevated and on wheels as we moved along. I hadn’t heard about the sound coming from the hatchlings. What an incredible process that would be to witness—her excavating and then carrying them to the water in her mouth. Hopefully, someday one of you will be in the right place at the exact right moment to witness, capture and share that moment with us.
Great post Patrick!
Hi Patrick! Yes they are wonderful mothers indeed… and bigger than males, I watched them defending their eggs from monitor lizards and snakes… they have to run and swim back and forth, and eggs are so many… this is moving. So intriguing the sex ratio, in sea turtles it is the opposite, the higher the temperature more females to be born. And vice versa ….
Great blog, Patrick! Crocodiles are not really my favourite animals, but they are still absolutely fascinating.
Great post Patrick! It is amazing that not one ranger or tracker has witnessed the burying of the eggs, nor the trek from the nest to the water once they are viable to survive in the water. I’ve only observed the ritual via nature specials on my local PBS channel. It is fascinating to watch this mammoth reptile gather up all the hatchlings in her massive jaws and transport them to the water. Perhaps this will be your lucky year!!
Good luck! Hope you catch that so you can share!!
Hi Patrick, thanks for the informing on the crocodiles and the way they go about laying their eggs. It is truely fascinating to read about the temperature determines the sex of the baby crocodiles and where she lays the eggs. I am sure with close observation you will be able to view the mother protecting her eggs.