One Bibron's thick-toed gecko, two fork-marked sand snakes, one inevitable outcome: an expired lizard.
On a recent visit to the Kgalagadi Transfrontier Park – a 38,000-square-kilometre spread of sandy savannah that straddles the South Africa-Botswana border in the south of the Kalahari Basin – Soo and Martyn Stroud just about stood on a pair of hunting snakes while exploring the area around their safari camp. The fork-marked sand snakes (Psammophis trinasalis) appeared to have teamed up for the hunt, but quickly slithered from view into some nearby vegetation before the Strouds could get a closer look.
"We went back about ten minutes later to see if they were still around," Soo Stroud told Wild Magazine, "and what do you know … one had started feasting on a tailless Bibron’s gecko (Chondrodactylus bibronii) from the head-end."
The Bibron's gecko – a member of one of South Africa's stockiest gecko species – had shed its tail in a failed attempt to escape the danger. This anti-predator tactic, known as "caudal autotomy", is common among these lizards ... but clearly the strategy is not always successful.
"Pretty soon we saw the second snake hovering around, waiting for a piece of the action," Stroud recalls. "It then moved in and went for the gecko's body section."
Snakes swallow their prey whole, which makes for a strict no-share policy when eating. The second sand snake was forced to abandon its attempted theft, retreating to some nearby vegetation to watch its rival scoff down the meal.
Fork-marked sand snakes are mildly venomous colubrids; however, their bites do not pose a threat to humans. Found from northwestern South Africa up into the Kalahari thornveld of Botswana and Namibia, the striking serpents dine mostly on lizards and rodents.
As for cooperative hunting, it's more likely that this was simply an opportunistic attempt by a second snake to nab an easy meal, rather than a genuine example of reptilian teamwork. In fact, according to Johan Marais, herpetologist and founder of the African Snakebite Institute, incidents like this sometimes result in one snake swallowing the other.
"I have found a pair of sand snakes sharing the same rock crevice," Marais adds, pointing out that it's possible that these snakes were hanging out together to take advantage of a fertile hunting ground.
To date, the only reliable evidence of coordinated hunting in the reptile realm comes to us from Cuban boas. In a study published last year, researchers observed the hunting habits of these bat-munching snakes in a cave in the West Indies, and found that the animals would deliberately position themselves close to one another to form a kind of "curtain of predation" dangling from the cave roof.
"They position themselves in a way that allows them to form a barrier across a cave passage," explains Vladimir Dinets of the University of Tennessee in Knoxville, who spent time observing the predators. "This significantly improves the effectiveness of the hunt, apparently because they can most effectively block the prey's flight path and easily intercept passing bats."
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Header image: Soo Stroud
Animal Behaviour
Predator vs Prey
In The Field
