Oh Noes! Not The Otters!

Ever since I worked in an aquarium which had a strong focus on conservation, I’ve been trying to get people to stop being afraid of sharks. Their bad rep is largely to due with movies like Jaws, where in reality they only kill 2-3 people a year, that’s far less than alligators, dogs, even coke machines kill, whereas humans kill between 40 and 100 million sharks a year. Not to mention the fact that there are hundreds of species of shark out there, and there are only really 3 you need to worry about when it comes to shark attacks.

But when I see stories like this, I feel my audience slipping away and back to their original notion that sharks are the bad guy. It seems as though the white sharks in California are murdering sea otters. I say murdered, because they don’t seem to be eating them, or killing them for any particuar reason.


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.”


Dammit white sharks. Otters are one of the cutest animals on the planet. You are not helping your rep in the slightest by massacring the little fur balls.

So, you may ask, if they’re not eating the otters, why are they just killing them? The fact is, no one really knows for sure. There are a couple of theories floating around, though


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.

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.


It could well be a combination of multiple factors, I guess. Although, if they are simply mistaking otters for sea lions, I hope they figure it out soon. It would be excellent irony if successful conservation campaigns of the two species simply results in one species killing off the other.




  1. Ichthyic says

    thanks for this. Interesting issue, to be sure.

    to the list of possibles I would add:

    -a large cohort of young white sharks due to increasing water temps being more favorable for white shark breeding (not generally from GW, but more due to the last eEl Niño). if the otter attacks drop off by next year, I would consider that support for this, provided there is control for the actual number of otters left. The large cohort should move on to larger and better prey quickly. the otters should bounce back after that.

  2. blf says

    The mildly deranged penguin explains that cheese and duck eggs and cheese, with scrambled twice–shark-bit otter and moar cheese, is a tasty breakfast. The otters in the OP are ones who got away.

    Alternatively, it’s the shark’s revenge for shark-fin soup.

  3. says

    Some species fight and kill other species to eliminate competition for food and resources. The diets of otters and sharks may be almost completely different, but that doesn’t mean sharks couldn’t mistake them for competition.

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