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Uploaded:2018-06-12
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If gulls just stole some of your chips while you were out trying to enjoy your lunch, you should feel lucky, because one species has recently developed a taste for live mammal meat!

Hosted by: Hank Green

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Sources:
http://www.icb.org.ar/descargas/Kelp%20gulls%20(Larus%20dominicanus)%20feeding%20on%20southern%20right.pdf
https://www.tandfonline.com/doi/abs/10.2989/1814232X.2015.1071718
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0139291
https://news.nationalgeographic.com/2015/08/150817-seals-seagulls-animals-science-predators-prey/
http://www.iucnredlist.org/details/22694329/0

Image Source:
https://commons.wikimedia.org/wiki/File:Arctocephalus_pusillus_2.jpg
[ ♪ INTRO ].

When you’re out enjoying a nice picnic on the beach you might occasionally find a gull trying to grab some of your chips. And you are like, “get away, just...stop bothering us!,” you know?

But just imagine for a moment that instead of your picnic basket those gulls were after... your flesh. Because one particular species of gull has recently developed a taste for live mammal meat, revealing just how adaptable these animals are. Most gulls eat fish or invertebrates like crabs, though they’ll occasionally snack on carcasses if they wash up.

They’re considered generalist, opportunistic feeders—they’ll pretty much take whatever they can get. But in the past 50 years or so, one species—the kelp gull—has developed a fondness for mammalian flesh, and learned just how to get it. It all started in Península Valdés, Argentina, a birthing ground for Southern right whales.

Giving birth is exhausting for everyone involved, so both new mamas and their babies like to relax and rest near the ocean surface. And that’s precisely when the gulls attack. These half a meter long, roughly 1 kilogram birds land on the whales’ backs and peel off pieces of skin until the wound becomes big enough that they can dig into the blubber underneath.

Gross, and mean! They mostly attack calves, because the babies haven’t learned how to arch their back or flick off the gulls off like their moms have. But what’s really terrifying, is that the gulls’ hunger for flesh is growing stronger!

Between 2003 and 2014, more than 50 calves died per year on average in Valdés, compared to only 8 per year the decade before. People aren’t 100 percent certain that all those deaths were caused by gulls, but scientists have noted an increase in the number and severity of attacks. The percentage of whales with gull-inflicted wounds rose from 2% in 1970s to a gruesome 99% in the 2000s according to a 2015 PLoS ONE study.

And the situation is now so bad that the gulls are considered a significant threat to right whale populations in the area. These guys got too smart! So since 2012, local governments have been culling some of these murder birds to try and protect the whales.

But... it’s not just Argentinian whales that have to keep an eye on the skies. Kelp gulls in Namibia have recently discovered a taste for… baby fur seal eyeballs. Like in something out of Alfred Hitchcock’s film The Birds, the gulls will repeatedly swoop down and peck at the eyeballs of unattended cape fur seal pups until the pups go blind.

Once they’re unable to see, more gulls join the feast and peck at juicy… wait I’m gonna stop I’m not gonna read what script even says it’s too sad. Let’s just say that the pups don’t make it. And since we’ve only known that gulls are preying on seal pups since 2014, no one knows yet if seal numbers will be affected.

These chilling behaviors likely developed in part because gulls have such a generalist diet, but also because quite good at observational learning, meaning they can learn new behaviors just from watching other gulls. So just a few likely discovered that squishy eyeballs and hunks of blubber are great sources of protein, fat and fluid, and others quickly cottoned onto the new snacks. Which explains why the behaviors are pretty much only seen in the same areas they began, though they could spread.

And we might also be to blame for the increase in the gull’s murderous behavior. Because of our activities, their usual prey is harder to come by. But this hasn’t hurt their numbers, as these flexible birds have learned to that our refuse is full of potential food.

So unlike many species, they do well in the places we’ve figuratively and literally trashed. I guess we should count ourselves lucky that they haven’t figured out what human eyeballs taste like… yet. Just have a… have a chip.

Have a chip. It’s fine, you can have my chips. Oh my god….

Thanks for watching this episode of SciShow! I know, it made your day so much better. If you like learning about wild animals and all of those wonderful and terrible things about world we live in, you might want to click on that subscribe button!

I know I did! [ ♪OUTRO ].