Scientists in California have been left perplexed by a wave of fatal shark attacks on sea otters, despite the fact that the predators have no interest in actually feeding on their furry victims. Talking to National Geographic, Tim Tinker of the US Geological Survey's Western Ecological Research Center explained that “as far as we can tell, a white shark has never eaten a sea otter,” and whenever a deadly attack takes place “we always get the whole animal back.”
While the odd shark taking out its aggression on another animal probably wouldn’t arouse too much confusion, the number of otters currently being massacred by Californian sharks is skyrocketing at a bafflingly sharp pace. According to Tinker, “shark-bitten animals now account for more than half of the [otter] carcasses we find,” and “exceeds all other sources of death combined.”
As a consequence, sea otter populations in parts of California have taken a hit, leading to concern among conservationists.
Researchers are able to discern the cause of death from the fact that bite marks on the otters’ bodies match those of white sharks, while several have also been found with teeth lodged in their fur and flesh. However, since the animals are little more than oversized hairballs, offering very little nutrition to predators, researchers are stumped as to why local sharks seem to have taken up this murderous fad.
One theory is that the sharks are simply mistaking otters for more nutritious prey like seals and sea lions, which are packed with calorific blubber. Only after biting them, however, do the sharks realize their mistake, and therefore leave their hairy leftovers to simply float away.
However, while this theory – which is also used to explain most shark attacks on humans – may well hold water, Tinker insists that we can’t be sure of the real reason behind this phenomenon, saying “the truth is, we’re in deep I-just-don’t-know land.”
The second part of the mystery concerns why such a sudden increase in shark attacks on otters is being observed right now. One potential explanation could be that successful conservation in recent years has led to increases in both white shark and otter populations, making encounters between the two more likely. An alternative theory, however, is that climate change is driving sharks further north, leading to increasing excursions into the otters’ habitat.
[H/T: National Geographic]