Crocodile digestive system

Raka; Our Resident Crocodile

Raka; Our Resident Crocodile

The warm weather has touched the landscape across the Crocodile River and the cold-blooded reptilians slide onto the sandbanks from the cool water to bask in the sunlight. Like logs, the creatures lie almost lifeless, soaking up the rays of sunshine with beady-eyes seemingly staring blankly ahead. Raka; our resident crocodile, slides his huge body out of the water; he is the largest of the crocodiles on this stretch and dominates many of the smaller crocs in these waters.

On this particular morning one of our guests, Tommy Weys, captures some incredible photographs of Raka in his natural habitat. An unfortunate impala has wandered too close and has been snagged. A fully grown crocodile, like Raka, will consume 20% of his body mass in a single sitting. While his main diet subsists of fish, birds and smaller antelope, he is not impartial to establishing his dominance over the River by consuming smaller crocodiles as well.

Raka’s digestive system is a well-oiled machine; perfected through thousands of years of evolution. His jaw cannot move other than to clamp down or open up; he therefore swallows prey whole. The meal will reach his stomach, and be met by hydrochloric stomach acid, as well as small stones (that he swallows) which help him to grind the food; due to an inability to chew. What’s even more interesting about this process is that his blood plays a vital role. Crocodiles have a special valve in the heart muscle linked to an aorta leading directly to the stomach, which miss the lungs completely. The blood that travels along to the stomach is thus rich in carbon dioxide, a crucial component in releasing more acid into the stomach to disintegrate prey. The influx in gastric acid means that Raka can devour and digest his prey faster than any other animal and dissolve bones that have made it into his system.

On further inspection of this prehistoric creature paleo-biologists discovered that a crocodile’s bite force averages around 16 460 newton’s; 10 000 newton’s more than that of a lion or hyena. Interestingly though, the muscles to open the jaws are not nearly as strong, which is why conservationists recorded relocating crocs by simply holding their mouths shut.

This by no means diminishes a crocodiles dangerousness; Raka will stalk his prey from below the water’s surface and lash out quickly, clamping his strong jaws shut around his victim, before pulling it back into the water where it will drown. Once shut, his jaws act as a vice-grip and will be near impossible to open.

Raka may remain in the River whilst feasting on his prize, but this is to minimise his vulnerability to other crocodiles attempting to make a claim on his meal. Once he is satisfied, he drags his large body from the cool waters and basks in the sun to digest his food. The warm rays of the sun, and the special second aorta, work in conjunction to speed up digestion; without these tools Raka’s meal would putrefy in his stomach.

As he lies along the lazy Crocodile River, we begin to notice how he, and other crocodiles around him, seem to share the same vacant expression and wide-open mouth. This social behaviour is not at all random, and shares with us another glimpse into the marvellous evolution these creatures have experienced. We already know that crocodiles are cold-blooded, so their body temperature is directly proportional to that of their environment. Along the Crocodile River, temperatures can sky-rocket to over 40° Celcius and Raka, as well as his other scaly comrades, can overheat. Lying on the sandbanks with their mouths agape works similarly to that of a dog panting; the cool breeze ripples over the crocodile’s mouth and cools the blood flowing around its brain. Once thoroughly cooled, the crocodiles will return to the depths of the Crocodile River.

Each day we watch, eagerly, as crocodilians put on a show for the Lodge’s visitors along the meandering Crocodile River. Raka; our resident crocodile and fiercest mascot, makes regular appearances to amaze and instill a sense of wonder and awe in those lucky enough to behold him; a living, breathing dinosaur of the deep.

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