WEBVTT - Squirrels: The Return 0:00:03.040 --> 0:00:06.800 Welcome to Stuff to Blow Your Mind, the production of iHeartRadio. 0:00:13.200 --> 0:00:14.880 Hey, welcome to Stuff to Blow your Mind. 0:00:15.000 --> 0:00:18.320 My name is Robert liamb and I am Joe McCormick. 0:00:18.360 --> 0:00:20.800 And today we are coming at you with the return 0:00:21.200 --> 0:00:24.319 of Squirrels to Stuff to Blow your Mind. If you 0:00:24.440 --> 0:00:27.159 are newer to the show and your memory does not 0:00:27.240 --> 0:00:31.080 go back this far, what year was it? Was it 0:00:31.120 --> 0:00:33.639 in twenty eighteen that we did a pair of episodes 0:00:33.640 --> 0:00:36.360 on squirrels that turned out to be real fan favorites, 0:00:36.400 --> 0:00:39.640 and I'll say host favorites too. We think about squirrels 0:00:39.920 --> 0:00:42.159 quite often, and I've never really thought about them the 0:00:42.200 --> 0:00:44.680 same way ever since we did those shows. 0:00:45.400 --> 0:00:51.640 That's right. They were quite popular talking about squirrels, their history, 0:00:51.840 --> 0:00:56.200 human and squirrel interactions, and what exactly squirrels eat. 0:00:56.840 --> 0:00:59.960 Yes, one of the big revelations from our research hall 0:01:00.120 --> 0:01:04.680 for those episodes it was about well, I don't know. 0:01:05.240 --> 0:01:07.240 I was going to say the darker side of squirrels, 0:01:07.280 --> 0:01:09.120 but I don't know. It's not dark, it's just nature. 0:01:09.160 --> 0:01:12.560 It's the more violent side of squirrels, the more carnivorous 0:01:12.560 --> 0:01:16.440 side of squirrels. The thing most people don't think of 0:01:16.480 --> 0:01:19.120 when they think of squirrels, which is scavenging meat from 0:01:19.200 --> 0:01:23.600 dead animals, attacking baby birds in their nests, maybe even 0:01:23.640 --> 0:01:27.680 preying on their own kind some kind, sometimes just squirrels 0:01:27.760 --> 0:01:29.680 eating of the flesh. 0:01:29.880 --> 0:01:32.000 Yeah, yeah, I know a lot of this breaks down 0:01:32.080 --> 0:01:35.160 just to the basic idea that squirrels are more complex 0:01:35.880 --> 0:01:38.840 then a lot of people give them credit for. You know, 0:01:39.640 --> 0:01:41.880 it's easy to look at a squirrel and think, oh, 0:01:41.959 --> 0:01:45.360 that's cute, without of course realizing that this is a 0:01:45.360 --> 0:01:52.160 wild animal. And yeah, they're not pure herbivores either, as 0:01:52.200 --> 0:01:55.840 we discussed in those episodes. But the thing about those 0:01:55.840 --> 0:01:57.800 episodes is that I think for many of us they 0:01:57.800 --> 0:02:00.760 made squirrels a lot cooler because if you did kind 0:02:00.760 --> 0:02:04.240 of dismiss squirrels as just, oh, well, they're the these 0:02:04.640 --> 0:02:06.920 who we see them every day. They're mundane. You know, 0:02:06.960 --> 0:02:09.600 they're out there trying to eat the bird seed. They're annoying, 0:02:09.600 --> 0:02:11.600 but that's it. You know. It gave us maybe a 0:02:11.600 --> 0:02:15.959 little more room to appreciate them. And a part of 0:02:16.000 --> 0:02:18.359 our appreciation that grew out of that is we busted 0:02:18.400 --> 0:02:21.040 out i think two different T shirt designs for our 0:02:21.080 --> 0:02:24.520 T shirt store. We don't promote our T shirt store 0:02:24.560 --> 0:02:26.840 as much as our T shirt store would like us to, 0:02:27.600 --> 0:02:30.080 in part because we don't depend upon it. It's just 0:02:30.120 --> 0:02:32.920 for fun. But if you go to our tea public 0:02:32.960 --> 0:02:34.560 store you can find a link at stuff to Blow 0:02:34.560 --> 0:02:36.359 your Mind dot com or check out the link tree 0:02:36.720 --> 0:02:40.600 on our Instagram. At STBYM podcast you'll see I moved 0:02:40.600 --> 0:02:42.079 them up to the top so you can see them 0:02:42.320 --> 0:02:44.480 rather easily. We have one that is the squirrels are 0:02:44.480 --> 0:02:46.840 Not what they seem and the other one is scug 0:02:47.000 --> 0:02:49.440 King of Rats. These are both squirrel shirts. They're both 0:02:49.520 --> 0:02:53.520 kind of metal looking. They're pretty good designs. I think 0:02:53.520 --> 0:02:54.440 people had some fun with. 0:02:54.400 --> 0:02:58.160 Them, agree. But there have been recent developments that caused 0:02:58.240 --> 0:03:00.840 us to return to the issue of squirrel once again. 0:03:01.240 --> 0:03:05.560 Multiple listeners over the past few weeks have excitedly gotten 0:03:05.600 --> 0:03:09.280 in touch to share news reports about a scientific paper 0:03:09.320 --> 0:03:12.800 out just this month in the Journal of Ethology, which 0:03:12.880 --> 0:03:17.160 returns to the topic of squirrels eating meat, and not 0:03:17.280 --> 0:03:21.640 just eating meat, but hunting and killing prey. So one 0:03:21.680 --> 0:03:25.359 of these messages, for example, came from our listener Daniel. 0:03:26.200 --> 0:03:28.880 He provided a link to the paper and said predatory 0:03:28.880 --> 0:03:32.720 carnivorous squirrels observed for the first time love the show. Ps, 0:03:32.760 --> 0:03:35.360 there's a Mountain Goats album called Beat the Champ and 0:03:35.440 --> 0:03:39.680 it is entirely about lucha libre no synth though off 0:03:39.680 --> 0:03:42.240 topic for today, but good to know. Nonetheless, Thank you, 0:03:42.320 --> 0:03:45.880 Thank you, Daniel. So if you are Daniel or any 0:03:45.920 --> 0:03:49.000 of the other listeners who sent this news our way, 0:03:49.600 --> 0:03:51.760 thanks for letting us know. And yep, you got your 0:03:51.760 --> 0:03:53.160 way here we are talking about it. 0:03:53.600 --> 0:03:55.480 We may have heard from a few other listeners over 0:03:55.520 --> 0:03:58.960 the years too, occasionally sending in some squirrel news I 0:03:59.000 --> 0:04:01.800 have found in homing through the squirrel news since twenty 0:04:01.840 --> 0:04:07.160 eighteen is that generally squirrels make headlines when there is 0:04:07.160 --> 0:04:10.960 blood involved. Yeah, so we'll be touching on a few 0:04:11.000 --> 0:04:12.080 different shades of this. 0:04:12.720 --> 0:04:16.279 Yeah. Warning that today's episode will include some gory details. 0:04:16.320 --> 0:04:19.400 But it's all nature, folks, and we got to face 0:04:19.520 --> 0:04:23.000 nature at some point, that's right. So what was found 0:04:23.080 --> 0:04:26.640 in this new predatory squirrel research. Well, let's go straight 0:04:26.640 --> 0:04:28.599 to the paper and have a look. So this paper 0:04:28.680 --> 0:04:30.360 has a long list of authors, but I'm going to 0:04:30.400 --> 0:04:33.720 read their names today. So this is by Jennifer E. Smith, 0:04:33.800 --> 0:04:39.680 Joey E. Ingbritson, Mackenzie m Minor, lc O Striker, Mari L. Podas, 0:04:39.800 --> 0:04:43.919 Tia A. Rivara, Lupen, mL tell Us, Jada C. Wall, 0:04:44.080 --> 0:04:47.200 Lucy M. Todd, and Sonya Wild And the paper is 0:04:47.240 --> 0:04:51.680 called Vole Hunting Novel, Predatory and Carnivorous Behavior by California 0:04:51.720 --> 0:04:56.120 Ground Squirrels, published in the Journal of Ethology twenty twenty four. 0:04:56.440 --> 0:04:58.080 As I said, I think it was out just this month, 0:04:58.120 --> 0:05:01.080 in December twenty twenty four. And so actually, I think 0:05:01.120 --> 0:05:04.000 this paper is really interesting because it's not just a 0:05:04.080 --> 0:05:09.360 documentation of a surprisingly violent behavior being carried out by squirrels. 0:05:09.360 --> 0:05:11.000 I mean, that's kind of that would be an interesting 0:05:11.040 --> 0:05:13.120 thing if that's all it were, But it actually places 0:05:13.160 --> 0:05:17.960 it within some bigger theoretical framework about mammal behavior. So 0:05:18.200 --> 0:05:22.440 the authors begin by talking about ways that animals adapt 0:05:22.440 --> 0:05:25.960 to their behavior to respond to changes within their environment. 0:05:26.400 --> 0:05:29.920 Sometimes we can have this misconception that humans are really 0:05:29.960 --> 0:05:34.520 the only animals that can adapt substantially to changing pressures 0:05:34.520 --> 0:05:36.760 in the world around them, and that all of the 0:05:36.800 --> 0:05:39.080 other animals are well, you know, they're not as smart 0:05:39.080 --> 0:05:41.680 as us, and their behavior is produced by a system 0:05:41.720 --> 0:05:44.640 of fixed instincts that are fundamentally rigid, so they just 0:05:44.680 --> 0:05:47.440 can't really change very much, even if it would benefit 0:05:47.480 --> 0:05:50.760 them to do so. Now, I think it's true that 0:05:50.880 --> 0:05:55.840 humans are especially adaptable. The flexibility of human behavior is 0:05:55.880 --> 0:05:58.200 really one of the things that makes us special in 0:05:58.200 --> 0:06:01.080 the animal kingdom and allows us to survive in basically 0:06:01.080 --> 0:06:05.120 any climate or ecological situation. But I think sometimes the 0:06:05.240 --> 0:06:07.960 knowledge of our specialness in this regard can lead us 0:06:07.960 --> 0:06:14.120 to underestimate the fascinating behavioral flexibility of other animals, especially 0:06:14.160 --> 0:06:19.680 other mammals, even superficially unassuming mammals like squirrels. So just 0:06:19.720 --> 0:06:22.400 because we're really good at something doesn't mean other animals 0:06:22.440 --> 0:06:25.640 can't do it at all. And as one kind of 0:06:25.680 --> 0:06:28.279 illustration here, early in the introduction of the paper, the 0:06:28.279 --> 0:06:32.560 authors bring up a really interesting animal behavior concept that 0:06:32.680 --> 0:06:35.080 I don't believe I had ever heard of before. If 0:06:35.080 --> 0:06:37.200 I had heard of it, I'd forgotten about it, and 0:06:37.320 --> 0:06:39.560 by the time I read this. But the concept is 0:06:39.560 --> 0:06:43.360 called the ecology of fear. And this is a bit 0:06:43.400 --> 0:06:45.440 of a tangent from the main paper here, But I 0:06:45.480 --> 0:06:47.520 thought this was so interesting I wanted to get into 0:06:47.560 --> 0:06:50.440 it in some detail. So one of the references they 0:06:50.480 --> 0:06:53.919 cite introducing this idea of the ecology of fear is 0:06:53.960 --> 0:06:57.000 a paper from the Journal of Mammalogy published in nineteen 0:06:57.080 --> 0:07:01.680 ninety nine by Brown, Landree, and Gurung called the Ecology 0:07:01.680 --> 0:07:05.520 of Fear, Optimal Foraging, Game Theory, and Trophic Interactions. What 0:07:05.600 --> 0:07:08.000 the authors of this paper point out is that it's 0:07:08.080 --> 0:07:12.520 easy to have an oversimplified view of how the presence 0:07:12.600 --> 0:07:16.920 of a predator can impact prey availability within an area. 0:07:17.520 --> 0:07:19.120 So I'm going to make up an example, and this 0:07:19.160 --> 0:07:21.920 scenario might not be perfectly valid in nature for the 0:07:21.960 --> 0:07:24.320 specific animals I'm using, but this is just to illustrate 0:07:24.320 --> 0:07:27.960 the principle. So imagine you've got a little park area 0:07:28.320 --> 0:07:32.000 and a bunch of rabbits living spread out across it, 0:07:32.440 --> 0:07:34.680 and they are being preyed on by a band of 0:07:34.760 --> 0:07:39.520 local foxes, and you're studying the predator prey interaction between 0:07:39.560 --> 0:07:43.360 the rabbits and the foxes. And then suddenly a new 0:07:43.480 --> 0:07:47.480 predator is introduced into this local environment. It's a cougar, 0:07:48.040 --> 0:07:50.600 and the cougar eats rabbits too. The foxes and the 0:07:50.640 --> 0:07:53.680 cougar both compete for the rabbits, So how does the 0:07:53.760 --> 0:07:57.640 cougar affect the availability of food for the foxes? A 0:07:57.840 --> 0:08:01.400 simple way of thinking is that the cougar kills and 0:08:01.480 --> 0:08:04.480 eats some of the rabbits. Thus some of the rabbits 0:08:04.480 --> 0:08:08.040 are removed from the population. Thus the number of rabbits 0:08:08.080 --> 0:08:11.320 available for the foxes to hunt is reduced. But the 0:08:11.360 --> 0:08:15.080 authors here point out that reality is more complicated than that. 0:08:15.720 --> 0:08:18.480 In the example I made up, the cougar might eat 0:08:18.520 --> 0:08:21.480 some of the rabbits, but the actual number that it 0:08:21.600 --> 0:08:24.360 kills and consumes compared to the total number of rabbits 0:08:24.400 --> 0:08:27.680 is relatively small. And yet the presence of the cougar 0:08:27.760 --> 0:08:31.600 could still greatly impact the availability of rabbit prey for 0:08:31.720 --> 0:08:35.080 the foxes. Now how would that be. It would be because, 0:08:35.240 --> 0:08:38.360 as the authors of this nineteen ninety nine paper say, quote, 0:08:38.640 --> 0:08:44.320 mammalian predator prey systems are behaviorally sophisticated games of stealth 0:08:44.520 --> 0:08:48.160 and fear. So what they're saying here is that prey 0:08:48.200 --> 0:08:52.880 mammals are not inert resources that are consumed like cookies 0:08:52.920 --> 0:08:56.000 from a jar. These are cookies that react. You know, 0:08:56.040 --> 0:08:58.680 they react to the fact that they are being eaten, 0:08:59.040 --> 0:09:01.360 and they are too very carrying degrees. Depending on the 0:09:01.400 --> 0:09:05.960 species adaptable, they can change their behavior in response to 0:09:06.000 --> 0:09:10.240 a threat. So the authors say that when studying predator 0:09:10.280 --> 0:09:14.320 prey interactions. In nature, there's actually a spectrum of different 0:09:14.440 --> 0:09:18.640 kinds of systems. So at one end of the spectrum 0:09:19.040 --> 0:09:23.079 you would have what the authors call population driven systems, 0:09:23.720 --> 0:09:25.880 and then at the other end of the spectrum you 0:09:25.960 --> 0:09:30.160 have what the authors call fear driven systems. In population 0:09:30.280 --> 0:09:34.480 driven systems, the main dynamic is predators killing prey, So 0:09:34.520 --> 0:09:36.600 the main variables are going to be like the number 0:09:36.640 --> 0:09:39.760 of predators and the number of prey, how many prey 0:09:39.800 --> 0:09:44.400 animals the predators eat, Whereas in fear driven systems, the 0:09:44.440 --> 0:09:50.120 presence of predators creates a condition of fear among prey, 0:09:50.559 --> 0:09:55.080 which causes prey to become harder to catch. So to 0:09:55.120 --> 0:09:57.559 go back to our example, if you have a cougar 0:09:57.640 --> 0:10:00.599 suddenly show up in this park, it could cause the 0:10:00.720 --> 0:10:04.640 rabbits to become significantly less available as prey, not just 0:10:04.760 --> 0:10:08.200 because they're literally disappearing from the population by being eaten, 0:10:08.600 --> 0:10:12.160 but because the rabbits are becoming more vigilant and more cautious. 0:10:12.440 --> 0:10:15.000 They're venturing out of shelter less. They might change what 0:10:15.160 --> 0:10:18.199 times of day they do things, they might change their 0:10:18.240 --> 0:10:21.959 foraging strategies. They might hide more or move away from 0:10:22.040 --> 0:10:28.960 any suspected predator earlier, earlier in possible detection. So in reality, 0:10:29.040 --> 0:10:33.280 a predator can functionally deplete the supply of prey animals 0:10:33.320 --> 0:10:36.480 in an area, not just by eating them, but by 0:10:36.480 --> 0:10:37.199 frightening them. 0:10:37.880 --> 0:10:41.400 Huh. I can't help but imagine a scenario where it's 0:10:41.400 --> 0:10:45.640 Gotham City, right, yeah, and maybe you're the local police force, 0:10:45.679 --> 0:10:49.160 and you have various stakeouts in place, you have various 0:10:49.280 --> 0:10:52.400 pending cases and so forth, and then there's a batman, 0:10:53.440 --> 0:10:59.600 essentially a new super predator preying on the criminal population 0:10:59.679 --> 0:11:03.480 of this and yeah, this's going to potentially interfere with 0:11:03.559 --> 0:11:06.800 everything that was going on. It's going to change the 0:11:07.360 --> 0:11:08.960 local criminal ecology. 0:11:09.320 --> 0:11:13.240 Yes, yeah, it'll change like police joker interactions. Not just 0:11:13.440 --> 0:11:15.920 because all of your local jokers and riddlers have been 0:11:15.920 --> 0:11:19.160 put in Arkham Asylum, but they might actually stop doing 0:11:19.280 --> 0:11:22.160 crimes or something, or do them in a less easy 0:11:22.200 --> 0:11:26.360 to detect way. Yeah, for another not quite perfect, but 0:11:26.400 --> 0:11:29.400 I think interesting analogy. I was thinking just about supply 0:11:29.440 --> 0:11:32.840 and demand in human economies. When you have a lot 0:11:32.840 --> 0:11:35.160 of people who want to buy the same product and 0:11:35.200 --> 0:11:39.000 that product is in limited supply, the buyers can end 0:11:39.080 --> 0:11:43.559 up limiting access to that product, not just by literally 0:11:43.640 --> 0:11:46.640 buying up and hoarding all of the products that exist, 0:11:47.080 --> 0:11:50.800 but by the secondary effect of driving up the price. 0:11:51.400 --> 0:11:53.880 Sellers realize demand is high, They're like, oh, a lot 0:11:53.880 --> 0:11:56.160 of people want to buy this, So the sellers raise 0:11:56.240 --> 0:11:59.040 their prices as much as they can, and this limits 0:11:59.080 --> 0:12:02.120 access to the product, even though the product doesn't actually 0:12:02.240 --> 0:12:05.280 vanish from the market, is just too expensive for a 0:12:05.320 --> 0:12:07.679 lot of the people who want it. Similarly, I think 0:12:07.679 --> 0:12:11.640 you could think of a predator as a predator by 0:12:11.679 --> 0:12:15.160 its presence bidding up the price of prey. It's not 0:12:15.240 --> 0:12:17.760 that the prey animals no longer exist. Some of them 0:12:17.800 --> 0:12:21.199 don't exist anymore, but for most of them they're still there, 0:12:21.559 --> 0:12:26.079 but they are increasingly expensive to acquire because they adjusted 0:12:26.120 --> 0:12:29.880 their behavior in response to a predator. And so the 0:12:29.920 --> 0:12:32.560 authors of this nineteen ninety nine paper summarize the effect 0:12:32.559 --> 0:12:37.160 by saying behavior buffers the system. A reduction in predator 0:12:37.280 --> 0:12:41.600 numbers should rapidly engender less vigilant and more catchable prey. 0:12:42.040 --> 0:12:46.600 The ecology of fear explains why big, fierce carnivores should 0:12:46.640 --> 0:12:50.800 be and can be rare in carnivore systems ignore the 0:12:50.840 --> 0:12:54.800 behavioral game at one's peril. So how does this tie 0:12:54.880 --> 0:12:57.800 into the study about squirrels where well, the authors of 0:12:57.840 --> 0:13:01.040 this twenty twenty four paper cite the ecology of fear 0:13:01.160 --> 0:13:05.200 as an example of how prey animals, including squirrels, are 0:13:05.440 --> 0:13:09.880 not well modeled by thinking of them as rigid, inflexible 0:13:09.960 --> 0:13:13.880 machines or as like a just an innert resource like 0:13:13.920 --> 0:13:17.560 cookies in a jar. Instead, we should understand that, to 0:13:17.920 --> 0:13:22.320 varying extents, squirrel species and other mammalian prey can change 0:13:22.360 --> 0:13:26.880 their behavior patterns when different pressures appear in surprising or 0:13:26.880 --> 0:13:31.640 perhaps even alarming ways. But mammals like squirrels don't only 0:13:31.800 --> 0:13:34.640 change their behavior in response to the threat of a predator, 0:13:35.120 --> 0:13:38.880 they also alter their behavior in response to changes in 0:13:38.920 --> 0:13:43.000 the availability of food. So from here the authors go 0:13:43.120 --> 0:13:46.320 into a big catalog of let's talk about all the 0:13:46.400 --> 0:13:51.120 documented instances of squirrels, specifically, in their case, the California 0:13:51.160 --> 0:13:55.600 ground squirrel eating meat. That's where they're going from here, 0:13:55.600 --> 0:13:57.200 and so they end up citing a paper that we 0:13:57.320 --> 0:14:01.760 talked about extensively in our older series on squirrels from 0:14:01.800 --> 0:14:06.080 twenty eighteen. The paper is called Squirrels as Predators by J. R. 0:14:06.200 --> 0:14:10.120 Callahan published in The Great Basin Naturalist nineteen ninety three. 0:14:10.160 --> 0:14:12.160 You remember this one, Rob Oh, absolutely, yeah. 0:14:12.200 --> 0:14:15.360 And of course if you're reading any subsequent papers about 0:14:15.679 --> 0:14:18.040 squirrels as predators, they all cited this one. 0:14:18.280 --> 0:14:19.400 Yeah, this seemed to be. 0:14:19.400 --> 0:14:23.400 A major publication in the world of squirrel predator research. 0:14:23.920 --> 0:14:26.840 Callahan really seemed to do the legworking cataloging all these 0:14:27.200 --> 0:14:30.480 different examples not just of squirrels eating meat, but actually 0:14:30.520 --> 0:14:35.000 functioning as predators. Now, there's an important distinction to make here, 0:14:35.040 --> 0:14:37.760 which is the difference between what you might call it 0:14:37.800 --> 0:14:44.360 just standard predation versus what is called facultative predation. An 0:14:44.360 --> 0:14:49.000 animal is generally categorized as a predator if it needs 0:14:49.080 --> 0:14:51.680 to be a predator, if it can be expected to 0:14:51.800 --> 0:14:54.160 catch and kill prey as a regular part of its 0:14:54.200 --> 0:14:56.240 behavior across its geographic range. 0:14:56.640 --> 0:14:59.440 Yeah, especially in the case of obligate carnivores. You know, 0:14:59.480 --> 0:15:03.280 where this creature has to hunt. Meat is what it eats. 0:15:03.640 --> 0:15:06.160 But also, I think you can think of some omnivores 0:15:06.240 --> 0:15:09.880 as just straight up predators if predation is a regular 0:15:09.960 --> 0:15:14.960 part of their acquisition of food. Meanwhile, a facultative predator 0:15:15.560 --> 0:15:20.840 is an animal that can sometimes optionally engage in predation 0:15:21.160 --> 0:15:24.920 if the circumstances are right, and that's typically what we're 0:15:24.920 --> 0:15:27.040 looking at with squirrels. I'm not aware of any squirrels 0:15:27.320 --> 0:15:31.240 that are consistent obligate predators, but there are a bunch 0:15:31.240 --> 0:15:34.200 of squirrels where the evidence is pretty good that while 0:15:34.200 --> 0:15:39.320 they are primarily herbivores, they will be omnivores when they 0:15:39.400 --> 0:15:42.480 need to be. And that's you know, the occasions might 0:15:42.520 --> 0:15:45.720 be rare, but many of them will shift strategies to 0:15:45.840 --> 0:15:49.160 eat foraged meat and sometimes even actively catch and kill 0:15:49.240 --> 0:15:53.520 live prey on an as needed or as available basis. 0:15:54.280 --> 0:15:57.160 Now this came up in our older episodes, but Callahan 0:15:57.240 --> 0:16:00.800 lists a bunch of different squirrel prey animals for the literature, 0:16:01.520 --> 0:16:11.200 just to gloss over them quickly. This includes birds, frogs, rats, lizards, rabbits, gophers, moles, snakes, fish, voles, ducks, 0:16:11.320 --> 0:16:17.280 wild turkeys, turtles, crabs, and salamanders. And sometimes this would 0:16:17.640 --> 0:16:20.520 this eating would involve the eating of the flesh, eating 0:16:20.600 --> 0:16:23.120 the meat. Sometimes it seems to be focused more on 0:16:23.360 --> 0:16:28.040 bones or joints, possibly for mineral supplementation in some squirrel species. 0:16:28.640 --> 0:16:31.160 But if you look at all of the previous research 0:16:31.240 --> 0:16:35.680 on squirrel predation. Taken together, it emphasized that the vast 0:16:35.800 --> 0:16:40.400 majority of the hunting done by squirrels was targeted at 0:16:40.440 --> 0:16:43.480 first of all insects or invertebrates, and then if you're 0:16:43.520 --> 0:16:47.080 looking at vertebrate prey, it would be relatively helpless juvenile 0:16:47.120 --> 0:16:50.920 prey such as actually eggs like bird eggs or bird 0:16:51.000 --> 0:16:52.440 hatchlings in the nest. 0:16:53.120 --> 0:16:55.760 Yeah, so memory serves this paper and also a paper 0:16:55.760 --> 0:16:58.560 that I'll be referring to later, looked at the fact 0:16:58.560 --> 0:17:00.680 that when you're studying all this, yeah, you do have 0:17:01.520 --> 0:17:05.720 reports of squirrel predation and squirrels eating meat and and 0:17:06.000 --> 0:17:08.719 and so forth. But then also you have a lot 0:17:08.760 --> 0:17:12.199 of data that has arrived at via analyzing the stomach 0:17:12.280 --> 0:17:17.040 contents of harvest squirrels. And of course that data doesn't 0:17:17.040 --> 0:17:19.639 all provide a lot of context. Like you you can 0:17:19.680 --> 0:17:21.320 look at it and say, well, they still mostly eat 0:17:21.520 --> 0:17:24.480 seeds or plants or whatever, but there is a certain 0:17:24.520 --> 0:17:27.560 amount of meat. As to how that meat was obtained, 0:17:29.400 --> 0:17:33.200 you have to draw conclusions sometimes because yeah, there's there there. 0:17:33.240 --> 0:17:36.520 Of course, you can scavenge, you can take out prey 0:17:36.640 --> 0:17:40.160 that are just weak or helpless, juvenile and so forth. 0:17:41.359 --> 0:17:43.760 But then there is that threshold, right that you cross 0:17:44.240 --> 0:17:51.480 into potentially actively hunting prey, actively hunting something that is 0:17:51.640 --> 0:17:54.760 that is not like wounded or dying, but is to 0:17:54.800 --> 0:17:58.600 some degree like a like a valid, healthy prey creature. 0:17:59.040 --> 0:18:01.760 That's right, And to some extent this ambiguity remained up 0:18:01.880 --> 0:18:04.840 until the time of this new paper. So the authors 0:18:04.880 --> 0:18:09.239 describe the landscape of squirrel meat eating research before their 0:18:09.280 --> 0:18:13.960 paper as follows. They write, quote, despite the growing consensus 0:18:14.000 --> 0:18:18.600 that many squirrel species opportunistically consume meat, much of the 0:18:18.640 --> 0:18:23.400 early evidence for predation is based on stomach contents or 0:18:23.760 --> 0:18:29.560 the killing of heterospecifics in captive settings eg. Zoos or traps. 0:18:30.359 --> 0:18:34.760 This makes it challenging to distinguish between scavenging and direct predation. 0:18:34.960 --> 0:18:37.320 So this is what you're saying, Rob, We're in this 0:18:37.400 --> 0:18:40.320 situation where you can find squirrels and like cut open 0:18:40.359 --> 0:18:42.320 their stomachs and say, oh, there's some meat in there, 0:18:42.320 --> 0:18:44.520 but we can't tell did it actually kill something, or 0:18:44.560 --> 0:18:47.000 did it just find something dead and eat part of it, 0:18:48.080 --> 0:18:51.199 or in these other cases, you might have evidence that 0:18:51.240 --> 0:18:53.840 the squirrel did kill and eat an animal, but it 0:18:53.880 --> 0:18:57.119 was an animal that was caught in a trap or something. 0:18:57.080 --> 0:18:58.840 Right, And I want to add an important caveat here 0:18:58.880 --> 0:19:01.639 about predation. I don't want to make it sound like 0:19:01.680 --> 0:19:05.960 true predation is a fair fight. We've covered enough examples 0:19:05.960 --> 0:19:07.800 of predation in the past to know that there are 0:19:07.800 --> 0:19:12.680 plenty of obligate carnivores, obligate predators who are still They're 0:19:12.720 --> 0:19:14.400 obviously not going to go out and say, all right, 0:19:14.480 --> 0:19:17.120 show me the strongest of the pack. No, the one 0:19:17.119 --> 0:19:19.320 I shall fight today. No, no, no, They're still they're 0:19:19.359 --> 0:19:23.560 still going after off you know, weekend, young, old, and 0:19:23.600 --> 0:19:29.520 so forth, because they're inherent increased risks involved in going 0:19:29.560 --> 0:19:30.480 after stronger prey. 0:19:30.800 --> 0:19:33.919 Predators use their coupons, they are looking for the super 0:19:33.920 --> 0:19:37.760 saver options. Yes, oh, but anyway, the authors here continue 0:19:37.800 --> 0:19:42.040 quote the direct study of hunting behavior by squirrels remains rare, 0:19:42.480 --> 0:19:45.159 and most reports in field settings are still limited to 0:19:45.200 --> 0:19:49.280 a single depredation event. So one thing this does bring up. 0:19:49.280 --> 0:19:53.000 I've seen a few people kind of comment that like, oh, 0:19:53.119 --> 0:19:56.119 you know, this isn't new. We have examples from before 0:19:56.680 --> 0:19:59.960 of squirrels eating meat, or squirrels, you know, report isolated 0:20:00.200 --> 0:20:03.680 reports of squirrels killing and eating animals. That is true, 0:20:03.720 --> 0:20:06.040 We do have these reports But what this new study 0:20:06.080 --> 0:20:12.439 contributes is extensive direct documentation, including video footage, of a 0:20:12.520 --> 0:20:16.119 specific species of squirrel, in this case, the California ground 0:20:16.160 --> 0:20:22.440 squirrel or Odospermophilus beachyi, hunting, killing, and eating adult vertebrate 0:20:22.520 --> 0:20:26.800 prey animals, specifically voles in the study. So how is 0:20:26.840 --> 0:20:29.080 this different than what we had before. Well, it's just 0:20:29.240 --> 0:20:34.280 a lot more observations of the predation behavior compared to 0:20:34.359 --> 0:20:37.800 the previous reports that were usually fairly isolated, and we 0:20:37.880 --> 0:20:41.000 have video evidence here. And they're not just going after 0:20:41.160 --> 0:20:43.679 juveniles or something that's caught in a trap or whatever. 0:20:43.880 --> 0:20:58.520 They're going after adult vertebrate prey animals. So a little sidebar, 0:20:58.760 --> 0:21:02.280 who are these California round squirrels the Odospermophylis beachy I. 0:21:03.440 --> 0:21:06.199 First of all, yes, they're cute. According to me, at 0:21:06.280 --> 0:21:08.520 least that's that's my opinion, Rob. I don't know if 0:21:08.560 --> 0:21:11.520 you share it, but yeah, they're cute little guys. 0:21:11.960 --> 0:21:15.440 I mean, yeah, I guess, I don't know. I feel 0:21:15.440 --> 0:21:17.320 like I'm you know, I'm not used to being around 0:21:18.560 --> 0:21:21.800 these California squirrels, but the squirrels i'm around here in Georgia, 0:21:22.480 --> 0:21:25.880 I think of them as I just know too much 0:21:25.920 --> 0:21:28.080 about them, and I see them too often. I think 0:21:28.119 --> 0:21:30.280 of them as like, it's hard for me to imagine 0:21:30.320 --> 0:21:34.000 someone thinking they're straight up adorable, because like I hear 0:21:34.080 --> 0:21:36.959 them on the fence, I see the effects of their 0:21:37.000 --> 0:21:39.879 claws on the fence. They're like furry grappling hooks, you know, 0:21:40.640 --> 0:21:42.920 like they're they're clearly tough creatures. I saw one fight 0:21:42.960 --> 0:21:47.040 off a hawk once in my backyard. Oh yeah, it's 0:21:47.680 --> 0:21:51.560 they're they're rough and tumble. So yes, cute, but with 0:21:51.640 --> 0:21:54.280 a number of caveats as far as my opinion of 0:21:54.320 --> 0:21:55.000 them goes. 0:21:54.920 --> 0:21:56.879 Well, I think it's going to be all caveats from 0:21:56.920 --> 0:22:00.639 here on out. So yes, they're cute. But I included 0:22:00.680 --> 0:22:02.399 for you to look at here in our outline. I 0:22:02.440 --> 0:22:05.879 found a picture hosted on the University of California Integrated 0:22:05.920 --> 0:22:10.080 Pest Management Program website. It's a picture of an avocado 0:22:10.240 --> 0:22:12.960 that has been gnawed on by a California ground squirrel. 0:22:13.400 --> 0:22:16.000 And I thought this picture was I don't know, it 0:22:16.119 --> 0:22:19.000 just struck me. It looks both beautiful the pattern that 0:22:19.080 --> 0:22:22.000 emerges and the different colors of the avocado flesh as 0:22:22.040 --> 0:22:25.520 it has been gouged and carved out by the rodent's teeth. 0:22:25.800 --> 0:22:29.359 But also I think it's hauntingly sad. 0:22:29.960 --> 0:22:32.719 Yeah, I have a real visceral reaction to this. There 0:22:32.760 --> 0:22:36.600 is something heartbreaking about it, potentially wasted avocado. I feel 0:22:36.600 --> 0:22:39.040 this one, like this one is saveable. I think I 0:22:39.040 --> 0:22:40.800 could get in there with a with a with a 0:22:40.920 --> 0:22:44.560 with a knife, cut off the part that's been fouled 0:22:44.600 --> 0:22:47.439 by the squirrel and you know, have plenty leftover for 0:22:47.480 --> 0:22:48.520 sandwiches and whatnot. 0:22:48.720 --> 0:22:50.480 You better do a good job because you don't know 0:22:50.520 --> 0:22:52.840 what the squirrel has been eating before. The avocado. 0:22:53.200 --> 0:22:54.960 Well, I think it's only going to seep in so far, 0:22:55.040 --> 0:22:57.520 and I'm gonna cut that part off and spread the rest. 0:22:59.280 --> 0:22:59.399 So. 0:22:59.640 --> 0:23:03.359 These California ground squirrels, the adults typically grow to around 0:23:03.440 --> 0:23:06.600 twenty two thirty centimeters long in the body, plus another 0:23:07.240 --> 0:23:10.320 half body length or so again with the tail. They 0:23:10.359 --> 0:23:13.400 have a modeled gray and brown fur on their backs 0:23:13.440 --> 0:23:16.000 and on the flanks, with usually lighter colored fur on 0:23:16.040 --> 0:23:19.240 the underside. They have a bushy tail. A couple of 0:23:19.280 --> 0:23:21.679 the sources I looked at mentioned that the tail is 0:23:21.720 --> 0:23:24.760 not as bushy as the common tree squirrels that you'll see, 0:23:24.800 --> 0:23:27.520 but it is bushy nonetheless, I don't know, medium bushy. 0:23:27.560 --> 0:23:31.200