Our recent study on cannibalism in southern African cobras caused quite a stir in the media. The work has been featured in a range of print media and we have even had airtime on some local radio shows. All the while, our radio-telemetered cape cobras were hanging out at Tswalu Kahalari Reserve doing cobra things. One of those cobras, a young male of a little over a meter in length, plain yellow in colour, with a faint juvenile throat band, is known to us as NN017. While all the media coverage about cannibal cobras was going on, the radio signal from NN017 seemed to disappear. It took some effort, but last February his signal was tracked to a deep burrow quite far outside of his typical (based on around 8 months of movement data and in situ observation) home range.
Fast forward to a few days ago when lab members Thilo and Mareike relocated him in a sociable weaver colony. Needing to retrieve the thermal data-logger surgically implanted into the snake, Thilo and Mareike captured it. There was only one small problem. Although the radio signal for NN017 was obviously coming from the snake they captured, that snake was absolutely not NN017! The snake emitting the radio signal was a much larger male, with a bright orange base-colour and intense black flecking, and importantly, no surgical scar! NN017 had been cannibalized by a larger male.
Although the radio signal for NN017 was obviously coming from the snake they captured, that snake was absolutely not NN017!
Left: NN017; Right: the source of NN017’s signal
Despite having one of our animals predated, we are delighted about this observation. Why? Well, in our paper on cannibalism we make several claims. Firstly, we claim that cannibalism is a common occurrence in our study system. If that claim is true, there is a fair expectation that one of our snakes would soon fall prey to another cobra. We know that the now-famous Hannibal (NN011) has eaten conspecifics, but had failed to find evidence for other cannibalism events in our telemetered snakes. Until now. Secondly, we speculate in the paper that cannibalism might be linked to intrasexual competition in male cobras. Importantly, NN017 was male, and this new snake (NN045) is male, providing another data point in favour of our hypothesis.
NN017 was male, and this new snake (NN045) is male, providing another data point in favour of our hypothesis.
It’s going to be fascinating to see how often we can detect such events, and it sure is fun speculating on how cannibalism (especially sex-biased cannibalism) influences population structure and interspecific interactions in our fascinating cobras.