The causeway that crosses the Sand River is always a hive of activity. It is essential to take a slow drive across and spend more than a few minutes scanning around to see what is playing out in all directions.
We had been marvelling over a pod of hippo that were quite disturbed by the presence of a large bull in their vicinity when tracker Bennet Mathonsi drew our attention to a boulder just left of us. No more than two metres from us was a young water (nile) monitor lizard with a rather large meal in its jaws. It had managed to catch a freshwater crab.
We noticed that the crab was still moving its legs, with which the lizard would thrash the crab from side to side. Much the same way a bird tries to soften insect prey before swallowing it, the lizard was attempting to break through the hard shell. If one takes a look at the front left side of the crab’s carapace, there is a large crack from where the lizard must have initially grabbed the crab. With large pincers, crabs are very adept at holding their own against predators. For those that have seen crabs in rock pools along the coast, whenever they are threatened they will turn to face you with pincers at the ready. The lizard must have worked this out quickly, managing to flip the crab over to avoid the powerful pincers.
Water monitor lizards normally feed on aquatic insects, small fish, rodents and have been known to raid crocodiles nests, devouring a large portion of their eggs. They are lightning quick with sharp claws and a powerful bite, making them formidable predators. With a dorso-ventrally flattened tail, they are excellent swimmers and may take to the water to escape potential threats. Interestingly, they fall within the same genus (Varanus) as the infamous Komodo dragons. Recent studies have revealed that Varanus species in fact have small venom glands, which were previously thought to have occurred only in snakes and one small group of lizards known as Beaded Lizards. The presence of venom is thought to aid in digestion more so than in the killing of prey as in snakes. With their powerful bite and well developed claws, one can see that the venom may not really be of too much use!
We found ourselves so enthralled by the lizard that before we knew it, we had spent well over 20 minutes observing the reptile attempting to eat its meal. The next day, the monitor was on the same rock, full-bellied basking in the sun…