WEBVTT - From the Vault: More Squirrels Eating Meat 0:00:06.240 --> 0:00:09.799 Hey, welcome to Stuff to Blow your Mind. It is Saturday, 0:00:09.800 --> 0:00:11.520 so we have a vault episode for you. This is 0:00:11.560 --> 0:00:15.160 going to be more squirrels eating meat than I think. 0:00:15.240 --> 0:00:20.040 The original publishing publication title was Squirrels the Return. This 0:00:20.079 --> 0:00:23.599 originally published one to twenty twenty five. This is where 0:00:23.600 --> 0:00:27.000 we're picking up on a topic we discussed in past 0:00:27.040 --> 0:00:32.640 episodes about research into to what degree squirrels eat meat 0:00:33.000 --> 0:00:34.440 and do they hunt well? 0:00:34.600 --> 0:00:35.120 Find out. 0:00:38.680 --> 0:00:49.040 Welcome to Stuff to Blow your Mind, the production of iHeartRadio. Hey, 0:00:49.120 --> 0:00:50.520 welcome to Stuff to Blow your Mind. 0:00:50.640 --> 0:00:53.960 My name is Robert liamb and I am Joe McCormick, 0:00:54.000 --> 0:00:56.440 and today we are coming at you with the return 0:00:56.840 --> 0:01:00.720 of Squirrels to Stuff to Blow Your Mind. Are newer 0:01:00.760 --> 0:01:03.280 to the show and your memory does not go back 0:01:03.320 --> 0:01:07.199 this far? What year was it? Was it in twenty 0:01:07.240 --> 0:01:10.080 eighteen that we did a pair of episodes on squirrels 0:01:09.920 --> 0:01:12.479 that turned out to be real fan favorites, and I'll 0:01:12.480 --> 0:01:16.199 say host favorites too. We think about squirrels quite often, 0:01:16.280 --> 0:01:18.440 and I've never really thought about them the same way 0:01:18.520 --> 0:01:20.320 ever since we did those shows. 0:01:21.040 --> 0:01:27.280 That's right, they were quite popular talking about squirrels, their history, 0:01:27.480 --> 0:01:31.880 human and squirrel interactions and what exactly squirrels eat. 0:01:32.480 --> 0:01:35.679 Yes, one of the big revelations from our research hall 0:01:35.760 --> 0:01:40.320 for those episodes it was about well, I don't know. 0:01:40.880 --> 0:01:42.880 I was going to say the darker side of squirrels, 0:01:42.920 --> 0:01:44.760 but I don't know. It's not dark, it's just nature. 0:01:44.800 --> 0:01:47.480 It's it's the more violent side of squirrels, the more 0:01:47.520 --> 0:01:51.960 carnivorous side of squirrels. The thing most people don't think 0:01:52.000 --> 0:01:54.560 of when they think of squirrels, which is scavenging meat 0:01:54.640 --> 0:01:59.000 from dead animals, attacking baby birds in their nests, maybe 0:01:59.040 --> 0:02:02.600 even preying on their own kind, some kind sometimes just 0:02:02.760 --> 0:02:05.120 squirrels eating of the flesh. 0:02:05.520 --> 0:02:07.800 Yeah, yeah, And a lot of this breaks down just 0:02:07.800 --> 0:02:11.720 to the basic idea that squirrels are more complex then 0:02:12.120 --> 0:02:14.440 a lot of people give them credit for. You know, 0:02:14.520 --> 0:02:17.600 they it's easy to look at a squirrel and think, oh, 0:02:17.600 --> 0:02:21.000 that's cute, without of course realizing that this is a 0:02:21.000 --> 0:02:27.799 wild animal. And yeah, they're not pure herbivores either, as 0:02:27.840 --> 0:02:31.480 we discussed in those episodes. But the thing about those 0:02:31.520 --> 0:02:33.440 episodes is that I think for many of us, they 0:02:33.440 --> 0:02:36.359 made squirrels a lot cooler because if you did kind 0:02:36.400 --> 0:02:39.959 of dismiss squirrels as just Oh, well, they're the these 0:02:40.320 --> 0:02:42.560 pre We see them every day. They're mundane, you know, 0:02:42.760 --> 0:02:45.240 they're out there trying to eat the bird seed. They're annoying, 0:02:45.240 --> 0:02:47.240 but that's it. You know. It gave us maybe a 0:02:47.240 --> 0:02:51.640 little more room to appreciate them, and a part of 0:02:51.639 --> 0:02:54.000 our appreciation that grew out of that is we busted 0:02:54.040 --> 0:02:56.680 out I think two different T shirt designs for our 0:02:56.720 --> 0:03:00.000 T shirt store. We don't promote our T shirts store 0:03:00.120 --> 0:03:02.200 or as much as our T shirt store would like 0:03:02.280 --> 0:03:05.440 us to, in part because we don't depend upon it. 0:03:05.440 --> 0:03:07.920 It's just for fun. But if you go to our 0:03:07.960 --> 0:03:09.960 tea public store, you can find a link at stuff 0:03:09.960 --> 0:03:11.760 to Blow Yourmind dot com or check out the link 0:03:11.800 --> 0:03:16.000 tree on our Instagram. At STBYM podcast, you'll see I 0:03:16.040 --> 0:03:17.560 moved them up to the top so you can see 0:03:17.560 --> 0:03:19.960 them rather easily. We have one that is the Squirrels 0:03:20.000 --> 0:03:22.040 are Not what they seem and the other one is 0:03:22.080 --> 0:03:24.919 scug King of Rats. These are both squirrel shirts. They're 0:03:24.960 --> 0:03:29.000 both kind of metal looking. They're pretty good designs. I 0:03:29.040 --> 0:03:30.079 think people had some fun with. 0:03:30.040 --> 0:03:33.800 Them, agree. But there have been recent developments that caused 0:03:33.880 --> 0:03:36.480 us to return to the issue of squirrels once again. 0:03:36.920 --> 0:03:41.200 Multiple listeners over the past few weeks have excitedly gotten 0:03:41.240 --> 0:03:44.960 in touch to share news reports about a scientific paper 0:03:44.960 --> 0:03:48.440 out just this month in the Journal of Ethology, which 0:03:48.520 --> 0:03:52.800 returns to the topic of squirrels eating meat, and not 0:03:52.920 --> 0:03:57.280 just eating meat, but hunting and killing prey. So one 0:03:57.320 --> 0:04:01.000 of these messages, for example, came from our listener Daniel. 0:04:01.840 --> 0:04:04.520 He provided a link to the paper and said, predatory 0:04:04.520 --> 0:04:07.720 carnivorous squirrels observed for the first time. Love the show. 0:04:07.880 --> 0:04:10.800 Ps there's a Mountain Goats album called Beat the champ 0:04:10.880 --> 0:04:13.880 and it is entirely about lucha libre no synth though 0:04:15.080 --> 0:04:17.880 off topic for today, but good to know. Nonetheless, Thank you, 0:04:17.960 --> 0:04:21.480 Thank you, Daniel. So if you are Daniel or any 0:04:21.560 --> 0:04:24.640 of the other listeners who sent this this news our way, 0:04:25.240 --> 0:04:27.400 thanks for letting us know. And yep, you got your 0:04:27.400 --> 0:04:28.840 way here we are talking about it. 0:04:29.240 --> 0:04:31.120 We may have heard from a few other listeners over 0:04:31.160 --> 0:04:34.599 the years too, occasionally sending in Some squirrel news I 0:04:34.640 --> 0:04:37.440 have found in combing through the squirrel news since twenty 0:04:37.480 --> 0:04:42.760 eighteen is that generally squirrels make headlines when there is 0:04:42.800 --> 0:04:46.560 blood involved. Yeah, so we'll be touching on a few 0:04:46.640 --> 0:04:47.720 different shades of this. 0:04:48.400 --> 0:04:51.920 Yeah, warning that today's episode will include some gory details. 0:04:51.960 --> 0:04:55.039 But it's all nature, folks, and we got to face 0:04:55.160 --> 0:04:58.640 nature at some point, that's right. So what was found 0:04:58.720 --> 0:05:02.279 in this new predatory squirrel research. Well, let's go straight 0:05:02.279 --> 0:05:04.239 to the paper and have a look. So this paper 0:05:04.320 --> 0:05:06.000 has a long list of authors, but I'm going to 0:05:06.040 --> 0:05:09.360 read their names today. So this is by Jennifer E. Smith, 0:05:09.440 --> 0:05:15.320 Joey E. Ingbritson, Mackenzie, M. Minor, LC oh Striker, Mari L. Podas, 0:05:15.440 --> 0:05:19.559 Tia A. Rivara Lupin, mL tell Us, Jada C. Wall, 0:05:19.720 --> 0:05:22.840 Lucy M. Todd, and Sonya Wild. And the paper is 0:05:22.880 --> 0:05:27.320 called Vole Hunting Novel Predatory and Carnivorous Behavior by California 0:05:27.360 --> 0:05:31.760 Ground Squirrels, published in the Journal of Ethology twenty twenty four. 0:05:32.080 --> 0:05:33.719 As I said, I think it was out just this month, 0:05:33.760 --> 0:05:36.720 in December twenty twenty four. And so actually I think 0:05:36.760 --> 0:05:39.640 this paper is really interesting because it's not just a 0:05:39.720 --> 0:05:45.000 documentation of a surprisingly violent behavior being carried out by squirrels. 0:05:45.000 --> 0:05:46.640 I mean, that's kind of that would be an interesting 0:05:46.680 --> 0:05:48.760 thing if that's all it were, but it actually places 0:05:48.800 --> 0:05:52.360 it within some some bigger theoretical framework about mammal behavior. 0:05:53.480 --> 0:05:57.560 So the authors begin by talking about ways that animals 0:05:57.640 --> 0:06:01.600 adapt to their behavior to respond it changes within their environment. 0:06:02.040 --> 0:06:05.559 Sometimes we can have this misconception that humans are really 0:06:05.600 --> 0:06:10.160 the only animals that can adapt substantially to changing pressures 0:06:10.160 --> 0:06:12.400 in the world around them, and that all of the 0:06:12.440 --> 0:06:14.719 other animals are well, you know, they're not as smart 0:06:14.720 --> 0:06:17.279 as us, and their behavior is produced by a system 0:06:17.360 --> 0:06:20.320 of fixed instincts that are fundamentally rigid, so they just 0:06:20.320 --> 0:06:23.080 can't really change very much, even if it would benefit 0:06:23.120 --> 0:06:26.400 them to do so. Now, I think it's true that 0:06:26.520 --> 0:06:31.480 humans are especially adaptable. The flexibility of human behavior is 0:06:31.520 --> 0:06:33.839 really one of the things that makes us special in 0:06:33.839 --> 0:06:36.719 the animal kingdom and allows us to survive in basically 0:06:36.760 --> 0:06:40.800 any climate or ecological situation. But I think sometimes the 0:06:40.880 --> 0:06:43.600 knowledge of our specialness in this regard can lead us 0:06:43.600 --> 0:06:49.760 to underestimate the fascinating behavioral flexibility of other animals, especially 0:06:49.800 --> 0:06:55.320 other mammals, even superficially unassuming mammals like squirrels. So just 0:06:55.360 --> 0:06:58.000 because we're really good at something doesn't mean other animals 0:06:58.080 --> 0:07:01.240 can't do it at all. And as one kind of 0:07:01.320 --> 0:07:03.919 illustration here, early in the introduction of the paper, the 0:07:03.960 --> 0:07:08.200 authors bring up a really interesting animal behavior concept that 0:07:08.320 --> 0:07:10.720 I don't believe I had ever heard of before. If 0:07:10.720 --> 0:07:12.840 I had heard of it, I'd forgotten about it and 0:07:12.960 --> 0:07:15.200 by the time I read this. But the concept is 0:07:15.240 --> 0:07:19.040 called the ecology of fear, and this is a bit 0:07:19.040 --> 0:07:21.080 of a tangent from the main paper here, But I 0:07:21.120 --> 0:07:23.160 thought this was so interesting I wanted to get into 0:07:23.200 --> 0:07:26.080 it in some detail. So one of the references they 0:07:26.120 --> 0:07:29.560 cite introducing this idea of the ecology of fear is 0:07:29.600 --> 0:07:32.680 a paper from the Journal of Mammalogy published in nineteen 0:07:32.720 --> 0:07:37.320 ninety nine by Brown, Landrei, and Gurung called the Ecology 0:07:37.360 --> 0:07:41.160 of Fear Optimal Foraging, Game Theory and Trophic Interactions. What 0:07:41.240 --> 0:07:43.640 the authors of this paper point out is that it's 0:07:43.720 --> 0:07:48.160 easy to have an oversimplified view of how the presence 0:07:48.280 --> 0:07:52.560 of a predator can impact prey availability within an area. 0:07:53.160 --> 0:07:54.760 So I'm going to make up an example, and this 0:07:54.800 --> 0:07:57.560 scenario might not be perfectly valid in nature for the 0:07:57.600 --> 0:07:59.880 specific animals I'm using, but this is just to illustrate 0:07:59.880 --> 0:08:03.160 the principle. So imagine you've got like a little park 0:08:03.240 --> 0:08:07.640 area and a bunch of rabbits living spread out across it, 0:08:08.120 --> 0:08:10.320 and they are being preyed on by a band of 0:08:10.400 --> 0:08:15.200 local foxes, and you're studying the predator prey interaction between 0:08:15.200 --> 0:08:19.000 the rabbits and the foxes. And then suddenly a new 0:08:19.120 --> 0:08:23.120 predator is introduced into this local environment. It's a cougar, 0:08:23.680 --> 0:08:26.240 and the cougar eats rabbits too. The foxes and the 0:08:26.280 --> 0:08:29.360 cougar both compete for the rabbits. So how does the 0:08:29.400 --> 0:08:33.280 cougar affect the availability of food for the foxes. A 0:08:33.480 --> 0:08:37.040 simple way of thinking is that the cougar kills and 0:08:37.120 --> 0:08:40.120 eats some of the rabbits. Thus, some of the rabbits 0:08:40.120 --> 0:08:43.679 are removed from the population. Thus the number of rabbits 0:08:43.720 --> 0:08:46.960 available for the foxes to hunt is reduced. But the 0:08:47.000 --> 0:08:50.760 authors here point out that reality is more complicated than that. 0:08:51.360 --> 0:08:54.120 In the example I made up, the cougar might eat 0:08:54.160 --> 0:08:57.120 some of the rabbits, but the actual number that it 0:08:57.240 --> 0:08:59.960 kills and consumes compared to the total number of rabbits 0:09:00.160 --> 0:09:03.600 relatively small. And yet the presence of the cougar could 0:09:03.640 --> 0:09:08.680 still greatly impact the availability of rabbit prey for the foxes. Now, 0:09:08.679 --> 0:09:11.120 how would that be. It would be because, as the 0:09:11.160 --> 0:09:14.839 authors of this nineteen ninety nine paper say, quote, mammalian 0:09:14.960 --> 0:09:20.840 predator prey systems are behaviorally sophisticated games of stealth and fear. 0:09:21.760 --> 0:09:24.640 So what they're saying here is that prey mammals are 0:09:24.679 --> 0:09:29.160 not inert resources that are consumed like cookies from a jar. 0:09:29.760 --> 0:09:32.640 These are cookies that react. You know, they react to 0:09:32.720 --> 0:09:35.199 the fact that they are being eaten, and they are 0:09:35.240 --> 0:09:38.880 two varying degrees depending on the species adaptable. They can 0:09:39.000 --> 0:09:43.120 change their behavior in response to a threat. So the 0:09:43.160 --> 0:09:47.360 authors say that when studying predator prey interactions in nature, 0:09:47.679 --> 0:09:52.520 there's actually a spectrum of different kinds of systems. So 0:09:52.720 --> 0:09:55.320 at one end of the spectrum you would have what 0:09:55.360 --> 0:10:00.040 the authors call population driven systems, and then at the 0:10:00.080 --> 0:10:02.600 other end of the spectrum you have what the authors 0:10:02.640 --> 0:10:07.160 call fear driven systems. In population driven systems, the main 0:10:07.320 --> 0:10:11.199 dynamic is predators killing prey, So the main variables are 0:10:11.200 --> 0:10:13.240 going to be like the number of predators and the 0:10:13.320 --> 0:10:17.000 number of prey, how many prey animals the predators eat, 0:10:17.240 --> 0:10:22.840 Whereas in fear driven systems, the presence of predators creates 0:10:22.880 --> 0:10:27.520 a condition of fear among prey, which causes prey to 0:10:27.600 --> 0:10:31.880 become harder to catch. So, to go back to our example, 0:10:32.280 --> 0:10:34.920 if you have a cougar suddenly show up in this park, 0:10:35.280 --> 0:10:39.079 it could cause the rabbits to become significantly less available 0:10:39.080 --> 0:10:42.440 as prey, not just because they're literally disappearing from the 0:10:42.480 --> 0:10:45.840 population by being eaten, but because the rabbits are becoming 0:10:45.920 --> 0:10:49.880 more vigilant and more cautious. They're venturing out of shelter less. 0:10:49.880 --> 0:10:52.360 They might change what times of day they do things. 0:10:52.960 --> 0:10:56.400 They might change their foraging strategies. They might hide more 0:10:56.480 --> 0:11:01.920 or move away from any suspected predator more earlier, earlier 0:11:01.920 --> 0:11:06.559 in possible detection. So, in reality, a predator can functionally 0:11:06.840 --> 0:11:10.160 deplete the supply of prey animals in an area, not 0:11:10.440 --> 0:11:12.839 just by eating them, but by frightening them. 0:11:13.520 --> 0:11:14.160 Huh. 0:11:13.840 --> 0:11:18.560 I can't help but imagine a scenario where it's Gotham City, right, Yeah, 0:11:18.559 --> 0:11:21.880 and maybe you're the local police force, and you you 0:11:21.920 --> 0:11:25.720 have various stakeouts in place, you have various pending cases 0:11:25.760 --> 0:11:29.840 and so forth, and then there's a batman, essentially a 0:11:29.880 --> 0:11:35.920 new super predator preying on the criminal population of the city. 0:11:36.360 --> 0:11:40.760 And yeah, it's going to potentially interfere with everything that 0:11:40.320 --> 0:11:44.600 was going on. It's going to change the local criminal ecology. 0:11:44.960 --> 0:11:48.920 Yes, yeah, it'll change. Like police joker interactions, not just 0:11:49.080 --> 0:11:51.560 because all of your local jokers and riddlers have been 0:11:51.559 --> 0:11:54.800 put in Arkham Asylum, but they might actually stop doing 0:11:54.920 --> 0:11:57.079 crimes or something, or do them in a in a 0:11:57.160 --> 0:12:01.880 less easy to detect way. Yeah, for another not quite perfect, 0:12:01.920 --> 0:12:04.400 but I think interesting analogy. I was thinking just about 0:12:04.640 --> 0:12:08.360 supply and demand in human economies. When you have a 0:12:08.360 --> 0:12:10.440 lot of people who want to buy the same product, 0:12:10.640 --> 0:12:14.280 and that product is in limited supply, the buyers can 0:12:14.480 --> 0:12:18.480 end up limiting access to that product, not just by 0:12:18.679 --> 0:12:22.199 literally buying up and hoarding all of the products that exist, 0:12:22.720 --> 0:12:26.440 but by the secondary effect of driving up the price. 0:12:27.040 --> 0:12:29.520 Sellers realize demand is high, They're like, oh, a lot 0:12:29.520 --> 0:12:31.800 of people want to buy this, So the sellers raise 0:12:31.880 --> 0:12:34.680 their prices as much as they can, and this limits 0:12:34.720 --> 0:12:37.760 access to the product, even though the product doesn't actually 0:12:37.880 --> 0:12:40.920 vanish from the market, is just too expensive for a 0:12:40.960 --> 0:12:43.319 lot of the people who want it. Similarly, I think 0:12:43.320 --> 0:12:47.280 you could think of a predator as a predator by 0:12:47.320 --> 0:12:50.800 its presence bidding up the price of prey. It's not 0:12:50.880 --> 0:12:53.400 that the prey animals no longer exist. Some of them 0:12:53.480 --> 0:12:56.839 don't exist anymore, but for most of them, they're still there. 0:12:57.200 --> 0:13:01.160 But they are increasingly expensive to a qui because they 0:13:01.200 --> 0:13:05.400 adjusted their behavior in response to a predator, and so 0:13:05.480 --> 0:13:07.839 the authors of this nineteen ninety nine paper summarize the 0:13:07.840 --> 0:13:12.280 effect by saying behavior buffers the system. A reduction in 0:13:12.360 --> 0:13:17.240 predator numbers should rapidly engender less vigilant and more catchable prey. 0:13:17.679 --> 0:13:22.240 The ecology of fear explains why big, fierce carnivores should 0:13:22.280 --> 0:13:26.440 be and can be rare in carnivore systems ignore the 0:13:26.480 --> 0:13:30.520 behavioral game at one's peril. So how does this tie 0:13:30.520 --> 0:13:33.439 into the study about squirrels where well, the authors of 0:13:33.480 --> 0:13:36.680 this twenty twenty four paper cite the ecology of fear 0:13:36.800 --> 0:13:40.840 as an example of how prey animals, including squirrels, are 0:13:41.080 --> 0:13:45.520 not well modeled by thinking of them as rigid, inflexible 0:13:45.600 --> 0:13:48.840 machines or as like a you know, just an innert 0:13:48.880 --> 0:13:52.839 resource like cookies in a jar. Instead, we should understand that, 0:13:53.120 --> 0:13:57.360 to varying extents, squirrel species and other mammalian prey can 0:13:57.520 --> 0:14:02.160 change their behavior patterns when different pressures appear in surprising 0:14:02.400 --> 0:14:06.840 or perhaps even alarming ways. But mammals like squirrels don't 0:14:06.880 --> 0:14:09.640 only change their behavior in response to the threat of 0:14:09.679 --> 0:14:13.600 a predator. They also alter their behavior in response to 0:14:13.800 --> 0:14:18.120 changes in the availability of food. So from here the 0:14:18.160 --> 0:14:21.480 authors go into a big catalog of let's talk about 0:14:21.560 --> 0:14:25.880 all the documented instances of squirrels, specifically, in their case, 0:14:25.960 --> 0:14:30.880 the California ground squirrel eating meat. That's where they're going 0:14:30.880 --> 0:14:32.600 from here. And so they end up citing a paper 0:14:32.640 --> 0:14:35.840 that we talked about extensively in our older series on 0:14:36.200 --> 0:14:40.240 squirrels from twenty eighteen. The paper is called Squirrels as 0:14:40.440 --> 0:14:44.040 Predators by J. R. Callahan, published in The Great Basin 0:14:44.120 --> 0:14:47.840 Naturalist nineteen ninety three. You remember this one, Rob, Oh, absolutely, yeah. 0:14:47.840 --> 0:14:51.000 And of course if you're reading any subsequent papers about 0:14:51.320 --> 0:14:54.560 squirrels as predators, they all cited this one. Yeah, this 0:14:54.640 --> 0:14:57.680 seemed to be a major publication in the world of 0:14:57.760 --> 0:14:59.040 squirrel predator research. 0:15:00.120 --> 0:15:03.200 Really seem to do the legworking cataloging all these different 0:15:03.200 --> 0:15:06.720 examples not just of squirrels eating meat, but actually functioning 0:15:06.880 --> 0:15:10.680 as predators. Now, there's an important distinction to make here, 0:15:10.680 --> 0:15:13.440 which is the difference between what you might call it 0:15:13.440 --> 0:15:19.960 just standard predation versus what is called facultative predation. An 0:15:20.000 --> 0:15:24.680 animal is generally categorized as a predator if it needs 0:15:24.720 --> 0:15:27.320 to be a predator if it can be expected to 0:15:27.440 --> 0:15:29.800 catch and kill prey as a regular part of its 0:15:29.840 --> 0:15:31.880 behavior across its geographic range. 0:15:32.280 --> 0:15:35.080 Yeah, especially in the case of obligate carnivores. You know 0:15:35.160 --> 0:15:38.200 where it has this creature has to hunt. Meat is 0:15:38.240 --> 0:15:38.920 what it eats. 0:15:39.280 --> 0:15:41.800 But also, I think you can think of some omnivores 0:15:41.880 --> 0:15:45.520 as just straight up predators if predation is a regular 0:15:45.600 --> 0:15:50.600 part of their acquisition of food. Meanwhile, a facultative predator 0:15:51.200 --> 0:15:56.480 is an animal that can sometimes optionally engage in predation 0:15:56.800 --> 0:16:00.800 if the circumstances are right. And that's what we're looking 0:16:00.800 --> 0:16:03.040 at with squirrels. I'm not aware of any squirrels that 0:16:03.160 --> 0:16:07.000 are consistent obligate predators, but there are a bunch of 0:16:07.040 --> 0:16:10.000 squirrels where the evidence is pretty good that while they 0:16:10.040 --> 0:16:15.320 are primarily herbivores, they will be omnivores when they need 0:16:15.360 --> 0:16:18.640 to be. And that's you know, the occasions might be rare, 0:16:18.960 --> 0:16:22.280 but many of them will shift strategies to eat foraged 0:16:22.320 --> 0:16:25.560 meat and sometimes even actively catch and kill live prey 0:16:26.080 --> 0:16:30.600 on an as needed or as available basis. Now this 0:16:30.680 --> 0:16:33.320 came up in our older episodes, but Callahan lists a 0:16:33.360 --> 0:16:37.240 bunch of different squirrel prey animals from the literature just 0:16:37.520 --> 0:16:46.840 to gloss over them quickly. This includes birds, frogs, rats, lizards, rabbits, gophers, moles, snakes, fish, voles, ducks, 0:16:46.960 --> 0:16:52.880 wild turkeys, turtles, crabs, and salamanders. And sometimes this would 0:16:53.280 --> 0:16:56.160 this eating would involve the eating of the flesh, eating 0:16:56.240 --> 0:16:58.760 the meat. Sometimes it seems to be focused more on 0:16:59.000 --> 0:17:03.680 bones or joints, possibly for mineral supplementation in some squirrel species. 0:17:04.280 --> 0:17:06.800 But if you look at all of the previous research 0:17:06.880 --> 0:17:11.320 on squirrel predation taken together, it emphasized that the vast 0:17:11.440 --> 0:17:16.040 majority of the hunting done by squirrels was targeted at 0:17:16.080 --> 0:17:19.119 first of all insects or invertebrates. And then if you're 0:17:19.160 --> 0:17:22.720 looking at vertebrate prey, it would be relatively helpless juvenile 0:17:22.760 --> 0:17:26.600 prey such as actually eggs like bird eggs or bird 0:17:26.640 --> 0:17:28.080 hatchlings in the nest. 0:17:28.760 --> 0:17:31.359 Yeah, so memory serves this paper and also a paper 0:17:31.400 --> 0:17:34.200 that I'll be referring to later, looked at the fact 0:17:34.200 --> 0:17:36.320 that when you're studying all this, Yeah, you do have 0:17:37.160 --> 0:17:42.919 reports of squirrel predation and squirrels eating meat and so forth, 0:17:43.359 --> 0:17:44.840 But then also you have a lot of data that 0:17:44.920 --> 0:17:49.920 has arrived at via analyzing the stomach contents of harvest squirrels, 0:17:50.119 --> 0:17:53.680 and of course that data doesn't all provide a lot 0:17:53.720 --> 0:17:56.040 of context, Like you can look at it and say, well, 0:17:56.080 --> 0:17:59.399 they still mostly eat seeds or plants or whatever, but 0:17:59.480 --> 0:18:02.440 there's a amount of meat. As to how that meat 0:18:02.520 --> 0:18:07.440 was obtained, you have to draw conclusions sometimes because yeah, 0:18:07.440 --> 0:18:10.800 there's there there. Of course, you can scavenge, you can 0:18:11.320 --> 0:18:14.919 take out prey that are just weak or helpless, juvenile 0:18:15.119 --> 0:18:18.720 and so forth. But then there is that threshold, right 0:18:18.760 --> 0:18:26.160 that you cross into potentially actively hunting prey, actively hunting 0:18:26.200 --> 0:18:29.159 something that is that is not like wounded or dying, 0:18:29.800 --> 0:18:32.800 but is to some degree like a like a valid, 0:18:33.080 --> 0:18:34.280 healthy prey creature. 0:18:34.680 --> 0:18:37.399 That's right, And to some extent this ambiguity remained up 0:18:37.520 --> 0:18:40.480 until the time of this new paper. So the authors 0:18:40.520 --> 0:18:44.920 describe the landscape of squirrel meat eating research before their 0:18:44.920 --> 0:18:49.600 paper as follows. They write, quote, despite the growing consensus 0:18:49.640 --> 0:18:54.240 that many squirrel species opportunistically consume meat, much of the 0:18:54.280 --> 0:18:59.040 early evidence for predation is based on stomach contents or 0:18:59.400 --> 0:19:04.320 the killing of heterospecifics in captive settings e g. Zoos 0:19:04.480 --> 0:19:09.000 or traps. This makes it challenging to distinguish between scavenging 0:19:09.160 --> 0:19:11.800 and direct predation. So this is what you're saying, Rob. 0:19:12.520 --> 0:19:14.959 We're in this situation where you can find squirrels and 0:19:15.000 --> 0:19:17.359 like cut open their stomachs and say, oh, there's some 0:19:17.400 --> 0:19:19.240 meat in there, but we can't tell did it actually 0:19:19.359 --> 0:19:21.800 kill something, or did it just find something dead and 0:19:21.880 --> 0:19:25.800 eat part of it, or in these other cases, you 0:19:25.920 --> 0:19:28.640 might have evidence that the squirrel did kill and eat 0:19:28.680 --> 0:19:30.800 an animal, but it was an animal that was like 0:19:30.880 --> 0:19:32.360 caught in a trap or something. 0:19:32.720 --> 0:19:34.479 Right, And I want to add an important caveat here 0:19:34.520 --> 0:19:37.280 about predation. I don't want to make it sound like 0:19:37.320 --> 0:19:41.600 true predation is a fair fight. We've covered enough examples 0:19:41.600 --> 0:19:43.399 of predation in the past to know that there are 0:19:43.440 --> 0:19:48.320 plenty of obligate carnivores, obligate predators who are still They're 0:19:48.359 --> 0:19:50.040 obviously not going to go out and say all right, 0:19:50.119 --> 0:19:52.760 show me the strongest of the pack. No, the one 0:19:52.760 --> 0:19:54.960 I shall fight today. No no, no, there's still they're 0:19:55.000 --> 0:19:59.800 still going after off weekend, young old and so forth, 0:20:00.280 --> 0:20:05.400 because they are inherent increased risks involved in going after 0:20:05.480 --> 0:20:06.120 stronger prey. 0:20:06.440 --> 0:20:09.560 Predators use their coupons, they are looking for the super 0:20:09.560 --> 0:20:13.840 savior options. Yes, oh, but anyway, the authors here continue quote, 0:20:14.000 --> 0:20:17.680 the direct study of hunting behavior by squirrels remains rare, 0:20:18.119 --> 0:20:20.800 and most reports in field settings are still limited to 0:20:20.840 --> 0:20:24.919 a single depredation event. So one thing this does bring up. 0:20:24.960 --> 0:20:28.640 I've seen a few people kind of comment that like, oh, 0:20:28.760 --> 0:20:31.800 you know, this isn't new. We have examples from before 0:20:32.359 --> 0:20:35.760 of squirrels eating meat, or squirrels, you know, report isolated 0:20:35.800 --> 0:20:39.280 reports of squirrels killing and eating animals. That is true, 0:20:39.359 --> 0:20:41.679 we do have these reports. But what this new study 0:20:41.720 --> 0:20:48.119 contributes is extensive direct documentation, including video footage, of a 0:20:48.160 --> 0:20:51.760 specific species of squirrel, in this case, the California ground 0:20:51.800 --> 0:20:58.080 squirrel or Odospermophilus beachyi, hunting, killing and eating adult vertebrate 0:20:58.160 --> 0:21:02.600 prey animals voles in the study. So how is this 0:21:02.640 --> 0:21:05.000 different than what we had before. Well, it's just a 0:21:05.040 --> 0:21:10.080 lot more observations of the predation behavior compared to the 0:21:10.119 --> 0:21:13.600 previous reports that were usually fairly isolated, and we have 0:21:13.720 --> 0:21:17.480 video evidence here. And they're not just going after juveniles 0:21:17.600 --> 0:21:19.720 or something that's caught in a trap or whatever. They're 0:21:19.760 --> 0:21:34.160 going after adult vertebrate prey animals. So a little sidebar, 0:21:34.400 --> 0:21:39.320 who are these California ground squirrels the Odospermophylis BEACHYI. First 0:21:39.400 --> 0:21:42.200 of all, yes, they're cute. According to me, at least 0:21:42.280 --> 0:21:44.679 that's my opinion, Rob, I don't know if you share it, 0:21:44.720 --> 0:21:47.080 but yeah, they're cute little guys. 0:21:47.600 --> 0:21:50.560 I mean, yeah, I guess, I don't know. 0:21:50.760 --> 0:21:52.280 I feel like i'm you know, I'm not used to 0:21:52.320 --> 0:21:56.520 being around these California squirrels. But the squirrels i'm around 0:21:56.520 --> 0:22:01.040 here in Georgia, I think of them as I just 0:22:01.080 --> 0:22:03.399 know too much about them and I see them too often. 0:22:03.480 --> 0:22:05.359 I think of them as like, it's hard for me 0:22:05.440 --> 0:22:09.280 to imagine someone thinking they're straight up adorable, because like 0:22:09.280 --> 0:22:12.359 I hear them on the fence, I see the effects 0:22:12.400 --> 0:22:14.879 of their claws on the fence. They're like furry grappling hooks, 0:22:15.320 --> 0:22:18.360 you know, like they're clearly tough creatures. I saw one 0:22:18.359 --> 0:22:21.320 fight off a hawk once in my backyard. Oh yeah, 0:22:22.240 --> 0:22:27.199 it's they're rough and tumble. So yes, cute, but with 0:22:27.280 --> 0:22:29.919 a number of caveats as far as my opinion of 0:22:29.960 --> 0:22:30.640 them goes. 0:22:30.560 --> 0:22:32.560 Well, I think it's going to be all caveats from 0:22:32.560 --> 0:22:35.840 here on out. So yes, they're cute, But Rob, I 0:22:35.880 --> 0:22:37.720 included for you to look at here in our outline. 0:22:37.960 --> 0:22:40.920 I found a picture hosted on the University of California 0:22:41.000 --> 0:22:44.960 Integrated Pest Management Program website. It's a picture of an 0:22:45.000 --> 0:22:48.600 avocado that has been gnawed on by a California ground squirrel. 0:22:49.040 --> 0:22:51.639 And I thought this picture was I don't know, it 0:22:51.760 --> 0:22:54.639 just struck me. It looks both beautiful the pattern that 0:22:54.720 --> 0:22:57.640 emerges and the different colors of the avocado flesh as 0:22:57.680 --> 0:23:01.159 it has been gouged and carved out by the rodent's teeth. 0:23:01.440 --> 0:23:05.000 But also I think it's it's it's hauntingly sad. 0:23:05.600 --> 0:23:08.280 Yeah, I have a real visceral reaction to this. It 0:23:08.400 --> 0:23:12.240 is something heartbreaking about it. Potentially wasted avocada. I feel 0:23:12.240 --> 0:23:14.040 this one, like this one is saveable. 0:23:14.359 --> 0:23:15.280 I think I could get in. 0:23:15.200 --> 0:23:17.560 There with a with a with a with a knife, 0:23:18.119 --> 0:23:21.200 cut off the part that's been fouled by the squirrel 0:23:21.320 --> 0:23:24.160 and you know, have plenty leftover for sandwiches and whatnot. 0:23:24.359 --> 0:23:26.119 You better do a good job because you don't know 0:23:26.160 --> 0:23:28.480 what the squirrel has been eating before. The avocado. 0:23:28.840 --> 0:23:30.600 Well, I think it's only going to seep in so far, 0:23:30.680 --> 0:23:32.760 and I'm going to cut that part off and spread 0:23:32.760 --> 0:23:33.160