Crocodilians: Natural History & Conservation: Crocodiles, Caimans, Alligators, Gharials

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Crocodilian images which reveal fascinating stories told from a visual perspective.

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"Can't I sleep in a bit?"

Baby saltwater crocodile hatching

It's May, and the last of the saltwater crocodile eggs are starting to hatch. This little hatchling doesn't look too enthusiastic about getting up just yet, though. Saltwater crocodile eggs take around 80 days to hatch, although incubation time is influenced by incubation temperature - warmer nests have faster development. Once the embryo's metabolism reaches a stage where available resources (e.g. oxygen) cannot be fulfilled, it's time to hatch! Up to 30 minutes before hatching, our intrepid baby crocodile starts to vocalise - a "pre-hatching" call which not only alerts the adult female, but also triggers nearby crocs to call from within their eggs. Upon hearing these musical pleas, the adult female walks determinedly over to the nest and begins to break it open - digging into the hardened mud and vegetation with her claws, and biting great chunks off using her jaws. It's clear why the hatchlings call the adult to open the nest - they'd never be able to break out by themselves.

In opening the nest, the female is inadvertantly triggering hatching - the vibrations she causes with her movement and digging are strong signals which cause most eggs to hatch. Those eggs which don't hatch, she picks up in her jaws and gently crushes the shell, assisting the baby crocodile to leave the egg. Once the nest is open, she seizes several visible or calling crocodiles in her jaws and carries them down to the water, making several trips to collect the rest. Those which she misses make their own way into the water, finding their siblings through the use of contact calls - special vocalisations which keep baby crocodiles together and close to the watchful gaze of their mother who can remain with them for several months.