[♪ INTRO] The date was July 30th, 2020, around 1700 hours.

The location: Frégate Island in the  Seychelles, off the coast of East Africa. A baby tern had fallen from its nest  and taken refuge on a log, where it was pursued, killed, and eaten by an  unexpected predator. . . a giant tortoise.

Yeah, you may have heard the  news: predatory tortoises. The incident was caught on video and  reported in the journal Current Biology, and it’s the first time any tortoise  has been caught in the act of deliberately killing and eating prey. Now we already knew that these  tortoises aren’t strictly vegetarian.

They’ve been known to chow down on  carrion, bones, and snail shells, which can be valuable sources of extra nutrients. But until now, we only had anecdotal  reports of them actually hunting. The tortoise in question is a female  Seychelles giant tortoise, and the chick is a lesser noddy tern, a species  that nests in trees on that island.

In the video footage, the tortoise  climbs up onto the log where the chick is standing, and a low-speed chase ensues. As the chick hops along the  log, the tortoise follows, neck extended, mouth open, and tongue retracted. This posture is typical of  aggressive behavior in tortoises.

It’s a clear sign that this tortoise  wasn’t just reaching for food, but planning to attack. After a minute and a half of this pursuit,  the chick reaches the end of the log. But baby terns can’t fly, and they instinctively  avoid dropping down to ground level, so there was nowhere to go.

The tortoise catches up to the chick   and, well . . . goes for the head. A single bite crushes the chick’s skull,  and then the tortoise swallows it whole. It’s shocking to watch, but what’s  really striking is that the tortoise seemed to know what it was doing.

Trapping a chick on a log is a pretty  effective hunting strategy, which makes researchers suspect this wasn’t this  particular predator’s first feathery dinner. Given the anecdotal reports of other  hunting tortoises, this might actually be a common behavior, but one that we’ve only  recently had the opportunity to witness. See, Frégate is a private  island managed for ecotourism.

The video was actually  captured by the island’s deputy conservation and sustainability manager. Conservation efforts in  recent years have successfully revived declining populations  of seabirds and tortoises. Chick-hunting could be a strange new  behavior developing among these tortoises.

Or it could be something they’ve done  for a long time, and now that their populations are recovering from endangerment,  they’re back to their old habits. But whether it’s new or just newly observed,  conservation efforts are giving us a chance to observe these species  interacting like we never have before. These tortoises aren’t the first  supposed vegetarians to supplement their diet with prey.

Numerous other herbivores,  including deer, sheep, and cattle, have been reported to eat insects,  fish, baby birds, and eggs. It may sound unusual, but animal-based  foods can be high in protein and minerals like calcium and phosphorus. That can be helpful if the local  vegetation is lacking in minerals, or if it’s a strenuous time of  year, such as mating season.

As for the tortoises, there’s still more to learn. Like how common this behavior is, or how  much nutrition they get from baby birds, or if there are other critters on the menu. What we do know is that this one has  killed before. . . and she will kill again.

Ok, enough about birds in the mouths of tortoises. Let’s talk about bacteria in the mouths of bears. Another study in Current Biology explored  nearly two centuries of bear spit to track how humans have contaminated the environment  with antibiotic-resistant bacteria.

And no, I’m not making this  up. Let’s break it down. We humans use a lot of antibiotics  to fight off harmful bacteria in our bodies and our food.

But improper use tends to drive bacteria  to develop resistance to those antibiotics, potentially developing into  even more dangerous strains. Resistant bacteria that develop in  hospitals or farms can infect humans, but they can also get into the  water and soil and infect wildlife, who can spread the bacteria to  other wildlife and back to us. That means it could be very helpful to  understand how antibiotic-resistant bacteria spread to wildlife, and how we can stop it.

So, researchers delved into a place  most humans avoid: bear mouths! Specifically, they collected dental plaque  from more than 50 preserved specimens of Scandinavian brown bears in the  Swedish Natural History Museum. Plaque is a time capsule for bacteria.  It can last for thousands of years in well-preserved museum specimens, keeping  bacterial remains trapped inside.

And signals of antibiotic resistance  can be found in that bacterial DNA. From the 1800s to the mid-1900s,  the bears’ bacteria showed low levels of antibiotic resistance, consistent with what we would  expect to see occurring naturally. But starting in the 1950s,  resistant bacteria increased, around the same time humans in  Sweden started using antibiotics on industrial levels.

We were accidentally creating resistant bacteria and spreading them to local wildlife. In fact, we were spreading them  really far, way more than we expected. Bears that lived far away from  human settlements had about the same amount of resistant  bacteria as those who lived close by.

This was a surprise, because previous  studies of wild populations of foxes, deer, and even tapirs have  shown that there is a connection between proximity to humans and higher  levels of antimicrobial resistance. The researchers aren’t sure  what caused this difference, but it suggests that when antibiotic  resistance gets into the environment, it really gets in there. But there was good news, too.

Starting in the 2000s, resistance  levels in the bears’ bacteria decreased. This was about 15 years after  policy changes in Sweden began reducing the use of antibiotics  in medicine and agriculture. Which shows that our actions  can contaminate the environment, but also that this contamination can be reversed.

This kind of microbial study could  prove very useful in tracking ways we’ve contaminated and polluted our surroundings, and museums are full of handy research subjects. Which means old museum specimens  could find new life helping us protect the environment, and ourselves. If you’re thinking that predatory tortoises  and protecting the environment through century-old bear spit are the two  weirdest things you’ve heard all week, I think you’ll probably like our  podcast.

It’s called SciShow Tangents. It’s where a bunch of smart people compete  to show off the weirdest science facts they can find, and it’s brought to you  by the same folks who make SciShow. If you’re interested, check it  out wherever you find podcasts.

It’s called SciShow Tangents. It’s a lot of fun. [ OUTRO ]