Aodhán Ó Gogáin, a PhD candidate in the School of Natural Sciences at Ireland’s Trinity College, uncovered an interesting new bit of information about a 300-million-year-old shark.
New fossils of faecal matter found in Canada revealed something a little unsettling — these sharks were feasting on their own young, possibly in times of low food supply. The findings were published Thursday in the journal Paleontology.
Within the fossils, there were loads of juvenile shark teeth. Scientists think that this species, Orthacanthus, lived in oily waters in swamps off the coast of Europe and North America, surrounded by hot jungles. When nothing else was available, these top predators might have dipped into their own population to keep from going hungry.
Scientists refer to this behaviour as “fillial cannibalism.”
Gogáin described what the shark would have looked like in a press release.
“Orthacanthus was a three-metre-long xenacanth shark with a dorsal spine, an eel-like body, and tricusped teeth,” he said. “There is already evidence from fossilized stomach contents that ancient sharks like Orthacanthus preyed on amphibians and other fish, but this is the first evidence that these sharks also ate the young of their own species.”
He said they were probably similar to the bull sharks of today, in the fact that they can survive in both brackish swamps and shallow oceans.Gogáin also mentioned that this may be part of the way fish started to colonize inland fresh waters.
Another co-author of the study, Dr. Howard Falcom-Lang of the Royal Holloway University of London, noted in the release that although the juvenile shark teeth were found in the faecal matter of adults, there is still some question as to why. But, because the time that these sharks lived at was also the time in which marine fish were moving into freshwater locations, there might have been a decreased food supply for the sharks. This could have caused them to eat their own young for survival — an ironic twist on trying to keep the species alive.
However, it looks like this isn’t the only time a species has been forced to cannibalise its own members in attempts to survive. Recently, seagulls in Washington State have started eating their own chicks, for example, because rising water temperatures have caused plankton, their main food source, to vanish.
So, while it may seem like an usually sinister phenomenon, cannibalistic ways appear to be a long-practiced final resort for animals who are trying to hold on in the face of changing environmental conditions.
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