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| Could Gorgosaurus survive in North America today?; This scenario has no people, so there is ice age megafauna | |
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| Tweet Topic Started: Jul 15 2012, 12:47 AM (7,201 Views) | |
| Admantus | Jul 15 2012, 12:47 AM Post #1 |
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Herbivore
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So, how would a population of gorgosaurus survive in north america today? Discuss. ( In this scenario, there are no humans alive and diseases don't count) Because gorgosaurus lived in the frigid north during the cretaceous, it'd have no problem surviving with it's feathered coat. Edited by Admantus, Jul 15 2012, 05:37 AM.
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| DinosaurMichael | Jul 15 2012, 07:50 PM Post #16 |
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Apex Predator
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Well it can happen, but it isn't common. You don't see Crocodiles eating Lions that much. Mostly just herbivores. |
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| Jinfengopteryx | Jul 15 2012, 09:56 PM Post #17 |
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Aspiring paleontologist, science enthusiast and armchair speculative fiction/evolution writer
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Same as with Cerato, but if it would luckily survive the new bacteria, it's immune system could adapt on them, however, it"s chances aren't very high. |
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| Ursus arctos | Jul 19 2012, 06:51 AM Post #18 |
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Autotrophic Organism
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I mean coolness of a possibility is weighed far more heavily than anything else. The views of the majority are just down right silly in their simplicity and lack of context. In the thread on Ceratosaurus, I discussed predictors of success of species introduced into new environments. Click this to view that post In it you can see how many factors that are considered important by posters in this thread, such as body size, were close to irrelevant. I would like to add some evidence of brain size being beneficial in practice. From "Large body and small brain and group sizes are associated with predator preferences for mammalian prey" by Susanne Shultz and Laura V. Finlayson. Large relative brain size was consistently associated with negative biases by predators. Thus, these results support Jerison’s (1973) conjecture that the evolutionary trend toward larger brains in prey species may be the result of a coevolutionary drive between predators and prey. Given that brain and body size appear to be strongly associated with predator diet choices, why do not all prey have relatively small body size and large brain size? The variation in body size biases shown by different predators indicates that there is unlikely to be an optimal body size that minimizes overall predation rates (except when body size is large enough to fall outside all/most predator body size ranges). Growing a large brain is a trickier proposition. Not only is it metabolically costly to invest in cognitive architecture but large brain size is also associated with a slowing down of maturation and first reproduction (Western 1979; Eisenberg and Wilson 1981; Isler and van Schaik 2009). Thus, life-history trade-offs, phylogenetic constraint, and multiple adaptive peaks result in some species opting out of a costly strategy and instead adopting alternative “fast” life-history strategies. In other words, species that have “cheap” behavioral characteristics are better off investing in maturing quickly and maximizing reproductive rates rather than maturing late and emphasizing survival. That small-brained species are associated with positive predator bias, which should consequently result in higher predation/mortality rates, is consistent with Sol et al. (2007), who demonstrated that large-brained bird species suffer lower mortality rates than smaller brained species. Thus, predation, in addition to other environmental factors, could be a mechanism for the differential mortality they reported. Although there were relationships between prey characteristics and selectivity, the strength of the relationships varied across predators. For example, although tigers showed significant biases toward terrestrial, large-bodied, and low-density prey, they did not appear to show any bias toward small-brained prey. The positive correlation between total brain size and selectivity is an artifact of body size effects as there was no relationship between residual brain size and selectivity. Conversely, canids, chimpanzees, and felids all showed biases toward small-brained prey. Canids also appear to be biased by prey group size and strata use and felids by population density and strata, whereas chimpanzees appear to be less influenced by other characteristics. Chimpanzees are very different from the other predators in that they are not obligate carnivores; vertebrate prey compose a seasonally variable (and minor) component of their overall diet. Thus, they may make decisions about prey choice using different criteria than the other predators. What these results do tell us is that predators key into prey characteristics differently, and any given antipredator strategy may not be effective against all predators. Brain size was negatively associated with predator biases in mixed and closed habitats, whereas group size was negatively associated with predator biases in open habitats. In complex mosaic habitats, a variety of potential escape strategies (e.g., refuge use, flight, crypsis) is likely to be of more benefit than in open habitats where the options would be limited to fleeing or safety in numbers. In open habitats, small-bodied species tended to gather in smaller groups than larger bodied species, even though group size was negatively associated with predator biases. There are several potential explanations for this behavior. The first is that the smaller bodied gazelles use mixed-species associations to augment group size (Fitzgibbon 1990b); thus, the average number of conspecific individuals within a group may not accurately reflect total group size. The second is that smaller bodied species are cryptic or restrict their habitat use to areas closer to cover, especially around calving where their young use “prone” responses by hiding in vegetation (Fitzgibbon 1990a). In contrast, larger bodied species are more likely to use open spaces and adopt communal defense against predators (especially in terms of protecting young) (Jarman 1974; Caro et al. 2004). For overall models, terrestrial strata use was associated with higher predator foraging biases than arboreal strata use. However, changing strata use to avoid the risks of terrestrial predators is an option for few of the prey species in our database (mainly primates). Interesting that tigers appear to be an exception among felids. Perhaps simply a result of chance, but perhaps the fact tigers also have a larger relative brain size than other felines reduces difficulties of taking larger brain prey. Now, lets move on to focus on competition among predators. In a simple example of there being a single shared prey species, and no other prey (including on intraguild predation) one animal having a higher predation rate on that prey will slowly increase its % of the relative predator biomass, until the other predator is extinct. This is the basic starting point. So far, the survival of a predator is determined not by whether it is capable of taking the prey, but if it is capable of locating, tracking, catching, and then finally killing prey more effectively than the other predators in the environment. Of course, things are more complicated than this. Niche separation allows many species to survive; one predator can be more effective in closed environments while another in open environments. Wolves prefer open environments and cougars more forested areas. Different predators can specialise on different species of prey. Where jaguars and cougars coexist, jaguars typically take larger prey and cougars smaller. However there is often still substantial overlap in niches-of course more direct competition helps explain. Intraguild predation models show how such systems can survive. The influence of vigilance on intraguild predation by Tristan Kimbrell, Robert D. Holt, and Per Lundberg is a great article. This raises a problem: IGP theory of two predator species sustained by a single prey resource predicts that such a system will be stable only if the intermediate predator is better at exploiting the shared prey than the top predator, and the top predator also gains significantly from consumption of the intermediate predator (Borer et al., 2003; Holt and Polis, 1997; Krˇ ivan and Diehl, 2005). The examples of Palomares and Caro (1999) suggest that in some cases mammalian top predator species kill but rarely consume intermediate predator species, and there is no indication that any of these interactions are unstable. To begin reconciling theory to observation, we start by considering why some mammalian predators go to the trouble of killing other predators and then not consuming them. The answer is killing of competitors. Further: Exploitative competition may not be the only process by which killing a competitor is important, however— vigilance levels of both the intermediate predator and the shared prey may be affected. If individual prey are vigilant, eliminating the intermediate predator could benefit the top predator by indirectly relaxing vigilance in the shared prey. Additionally, if eliminating individual intermediate pre- dators makes others of that species more vigilant, and there is a tradeoff between vigilance and exploitative abilities, the intermediate predator may become a less efficient compe- titor for the prey, again benefiting the top predator. Prey vigilance has been observed to be important for predator–prey interactions in a number of mammalian systems (FitzGibbon, 1989, 1990; Hunter and Skinner, 1998; Laundre et al., 2001). One consequence of prey vigilance is that prey have a reduced food intake rate because vigilance interferes with foraging (Fortin et al., 2004; Illius and FitzGibbon, 1994), but predators also have a reduced food intake rate due to the decrease in prey vulnerability (FitzGibbon, 1989). There is less direct evidence for top predator species inducing vigilance behavior in mammalian intermediate predator species. Durant (2000) found, however, that cheetahs listening to playbacks of lion vocalizations are much less likely to hunt after hearing the playback, and often move away from the area of the playback. Thus, vigilance by the intermediate predator to predation from a top predator may reduce its efficiency in hunting a shared prey species. Here is some example info on influence and types of vigilance behaviour, going beyond frequency of breaks to scan for predators: 1. Many studies have investigated why males and females segregate spatially in sexually dimorphic species. These studies have focused primarily on temperate zone ungulates in areas lacking intact predator communities, and few have directly assessed predation rates in different social environments. 2. Data on the movement, social affiliation, mortality and foraging of radio-collared African buffalo (Syncerus caffer) were collected from 2001-06 in the Kruger National Park, South Africa. 3. The vast majority of mortality events were due to lion (Panthera leo) predation, and the mortality hazard associated with being an adult male buffalo in a male-only 'bachelor' group was almost four times higher than for adult females in mixed herds. The mortality rates of adult males and females within mixed herds were not statistically different. Mortality sites of male and female buffalo were in areas of low visibility similar to those used by bachelor groups, while mixed herds tended to use more open habitats. 4. Males in bachelor groups ate similar or higher quality food (as indexed by percentage faecal nitrogen), and moved almost a third less distance per day compared with mixed herds. As a result, males in bachelor groups gained more body condition than did males in breeding herds. 5. Recent comparative analyses suggest the activity-budget hypothesis as a common underlying cause of social segregation. However, our intensive study, in an area with an intact predator community showed that male and female buffalo segregated by habitat and supported the predation-risk hypothesis. Male African buffalo appear to trade increased predation risk for additional energy gains in bachelor groups, which presumably leads to increased reproductive success. From here. Animal movements are very commonly linked to efforts to avoid predation risk. Examples are fairly easy to find. Back to the article on vigilance and intraguild predation. First it creates two models of a single prey species and two competing predators. Both are equally lethal to non-vigilant prey, but vigilance has a greater impact on the ability of the prey to avoid the top predator than to avoid the intermediate predator. In one model the vigilance of prey is made to be constant, and in the other it is vigilance of the intermediate predator. ![]() The top predator is unable to survive if it doesn't kill the intermediate predator. As a note, the article also contained another model, with two prey species. Trying to represent lions, cheetahs, Thomson's gazelle, and wildebeest the top predator was more effective at preying on one, and the intermediate predator a more effective predator than the other. Basically, compared to the above, they added a prey source the top predator is better at using than the intermediate. ![]() The important lesson here however is this: if a predator isn't as effective at catching and consuming the available prey than another, for it to be able to survive in the ecosystem it must also kill the other predators-to decrease the vigilance of the prey (which in the model decreased the difference in predatory ability between the two), increase vigilance of the predator (decreasing its predatory ability), as well as taking energy from the intermediate predator and giving some amount to the top (proportional to consumption rate in the graphs). How would Gorgosaurus compare to the other predators? Vigilance of prey would be much more effective at deterring Gorgosaurus predation than it would be at deterring any of the other mammalian predators. Gorgosaurus is far taller (especially compared to a crouching feline) and larger. Ignoring behavioral abilities and flexibility that could make differences. The lethality without influence of vigilance is also much loewr for Gorgosaurus for most prey animals. Gorgosaurus, while it would have been much better at the killing part, lags greatly in ability to catch prey. This goes beyond the running speed problem: separating out a members of a herd is not easy. Gorgosaurus would lag well behind the other predators in ability to catch most prey, putting it at a large disadvantage compared to them when it comes to lethality. The question is not whether gorgosaurus can, under certain circumstances, catch them at all-it is how it compares to the competition. Mammoths would be Gorgosaurus's best bet, but I wouldn't count on them being more effective predators on them than the likes of Homotherium (which were probably very effective predators of the young). Besides the problem of mammoth vigilance. Modern elephants can be extremely vigilant. In the book "Silent Thunder" the author Katy Payne, for example, recounts going on a trip to see the rare (heavily poached) desert elephants. During the week long journey they only saw two elephants: their guide pointed out, which they could see with their binocular, two elephants running away from them reaching their trunks into their mouths to draw up water from their stomachs and pouring it onto their backs to allow themselves to continue running in the heat. They recognized humans from a great distance away (remember: they needed binoculars) and immediately put extremely drastic effort into getting away. Elephants do not take risks (one problem is with people most elephants have know idea how dangerous we are-they see countless of us and get along fine, and then randomly someone with a gun shoots them all leaving no/few survivors to learn the lesson). They reproduce extremely slowly and late in their lives, and are adapted for not taking risks larger than what would allow them to live a very long one. Besides the life history of elephants being focused on avoiding risk/danger/death to live a long life at the cost of very low productivity, that last part is another problem: low productivity. Rabbits can support many predators, breeding very quickly-> a lot of rabbits that predators can kill and eat. Not the life history plan of an elephant, which can't support much mortality. Their focus is almost entirely on avoiding it. Not that rabbits aren't pretty good at avoiding it too-they're very fast and causing lots of trouble in places like Australia. So the question now is: how dangerous would Gorgosaurus be to the North American predators? Consider the vigilance shown by brown bears when they are aware they're being tracked (iffy with humans, due to how many of us their are that don't track them). Enos Mills tracking of the bear named "Old Timberline" is a great read, published in his book "The Grizzly" in the chapter "Trailing without a Gun" (old enough to be available in full on Google Books). Old Timberline becomes aware of his presence on page 127-and the bear's reaction to the circumstances truly demand respect. Well worth a read. I've also in the past posted the story of the Giefer Grizzly-a wild bear equipped with a radio collar sentenced to death, but managed to avoid all the professional hunters equipped with his frequency, countless traps, etc. In the end he was killed by a random bear hunter while in the safe haven of Canada (at one point in his life he learned that pursuit stops once he crosses the imaginary line separating the US and Canada)-one can't differentiate random civilians (who are no threat and a complete waste of time and energy to avoid) from random civilians with guns and a bear license. Bears are relatively larger brained, however the other carnivores (who are far closer to the bear than to Gorgosaurus) are also aided by speed, efficient locomotion, and (for some small ones) tree climbing or burrowing ability. What is the likelihood that they will let themselves be caught with any sort of regularity? It is likely that most predator species won't even need significant levels of vigilance to avoid predation. Wolves for example would have an easier time pestering gorgosaurus than they do bears (bears can rotate much more quickly, and wolves are more efficient and faster runners than both) and they do not make much of an effort at all to keep their distance-yet still suffer very few bear-caused mortalities. So, I've presented two methods of assessing the situation: a) Studies determining relationship between characteristics of introduced species and whether they succeed or fail to survive when introduced to a new environment. Result: extremely unlikely. b) Predator prey models that discuss circumstances needed for multiple competing species to coexist. Conclusion: unlikely. a) is of course better for predicting success than b) as a) attacks the problem directly (and if we tried b) on all the species used in the samples to produce the results of the studies falling under a) we wouldn't make predictions nearly as well because b) simply attacks a different problem than what we're discussing here), yet for some reason no other posters have given method a) much attention (or simply failed horribly at predicting the relative importance of the different factors). Yet, despite overwhelming evidence, because Gorgosaurus is cool most people vote for it as an animal better adapted to survive in today's environment than the modern animals whose much longer evolutionary histories have culminated to produce it. |
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| Superpredator | Jul 19 2012, 04:26 PM Post #19 |
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Apex Predator
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What Ursus Arctos said! What? How dare you accuse me of copying?!?! |
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| Admantus | Jul 20 2012, 01:57 AM Post #20 |
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Herbivore
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Click this to view that post In it you can see how many factors that are considered important by posters in this thread, such as body size, were close to irrelevant. I would like to add some evidence of brain size being beneficial in practice. From "Large body and small brain and group sizes are associated with predator preferences for mammalian prey" by Susanne Shultz and Laura V. Finlayson. Large relative brain size was consistently associated with negative biases by predators. Thus, these results support Jerison’s (1973) conjecture that the evolutionary trend toward larger brains in prey species may be the result of a coevolutionary drive between predators and prey. Given that brain and body size appear to be strongly associated with predator diet choices, why do not all prey have relatively small body size and large brain size? The variation in body size biases shown by different predators indicates that there is unlikely to be an optimal body size that minimizes overall predation rates (except when body size is large enough to fall outside all/most predator body size ranges). Growing a large brain is a trickier proposition. Not only is it metabolically costly to invest in cognitive architecture but large brain size is also associated with a slowing down of maturation and first reproduction (Western 1979; Eisenberg and Wilson 1981; Isler and van Schaik 2009). Thus, life-history trade-offs, phylogenetic constraint, and multiple adaptive peaks result in some species opting out of a costly strategy and instead adopting alternative “fast” life-history strategies. In other words, species that have “cheap” behavioral characteristics are better off investing in maturing quickly and maximizing reproductive rates rather than maturing late and emphasizing survival. That small-brained species are associated with positive predator bias, which should consequently result in higher predation/mortality rates, is consistent with Sol et al. (2007), who demonstrated that large-brained bird species suffer lower mortality rates than smaller brained species. Thus, predation, in addition to other environmental factors, could be a mechanism for the differential mortality they reported. Although there were relationships between prey characteristics and selectivity, the strength of the relationships varied across predators. For example, although tigers showed significant biases toward terrestrial, large-bodied, and low-density prey, they did not appear to show any bias toward small-brained prey. The positive correlation between total brain size and selectivity is an artifact of body size effects as there was no relationship between residual brain size and selectivity. Conversely, canids, chimpanzees, and felids all showed biases toward small-brained prey. Canids also appear to be biased by prey group size and strata use and felids by population density and strata, whereas chimpanzees appear to be less influenced by other characteristics. Chimpanzees are very different from the other predators in that they are not obligate carnivores; vertebrate prey compose a seasonally variable (and minor) component of their overall diet. Thus, they may make decisions about prey choice using different criteria than the other predators. What these results do tell us is that predators key into prey characteristics differently, and any given antipredator strategy may not be effective against all predators. Brain size was negatively associated with predator biases in mixed and closed habitats, whereas group size was negatively associated with predator biases in open habitats. In complex mosaic habitats, a variety of potential escape strategies (e.g., refuge use, flight, crypsis) is likely to be of more benefit than in open habitats where the options would be limited to fleeing or safety in numbers. In open habitats, small-bodied species tended to gather in smaller groups than larger bodied species, even though group size was negatively associated with predator biases. There are several potential explanations for this behavior. The first is that the smaller bodied gazelles use mixed-species associations to augment group size (Fitzgibbon 1990b); thus, the average number of conspecific individuals within a group may not accurately reflect total group size. The second is that smaller bodied species are cryptic or restrict their habitat use to areas closer to cover, especially around calving where their young use “prone” responses by hiding in vegetation (Fitzgibbon 1990a). In contrast, larger bodied species are more likely to use open spaces and adopt communal defense against predators (especially in terms of protecting young) (Jarman 1974; Caro et al. 2004). For overall models, terrestrial strata use was associated with higher predator foraging biases than arboreal strata use. However, changing strata use to avoid the risks of terrestrial predators is an option for few of the prey species in our database (mainly primates). Interesting that tigers appear to be an exception among felids. Perhaps simply a result of chance, but perhaps the fact tigers also have a larger relative brain size than other felines reduces difficulties of taking larger brain prey. Now, lets move on to focus on competition among predators. In a simple example of there being a single shared prey species, and no other prey (including on intraguild predation) one animal having a higher predation rate on that prey will slowly increase its % of the relative predator biomass, until the other predator is extinct. This is the basic starting point. So far, the survival of a predator is determined not by whether it is capable of taking the prey, but if it is capable of locating, tracking, catching, and then finally killing prey more effectively than the other predators in the environment. Of course, things are more complicated than this. Niche separation allows many species to survive; one predator can be more effective in closed environments while another in open environments. Wolves prefer open environments and cougars more forested areas. Different predators can specialise on different species of prey. Where jaguars and cougars coexist, jaguars typically take larger prey and cougars smaller. However there is often still substantial overlap in niches-of course more direct competition helps explain. Intraguild predation models show how such systems can survive. The influence of vigilance on intraguild predation by Tristan Kimbrell, Robert D. Holt, and Per Lundberg is a great article. This raises a problem: IGP theory of two predator species sustained by a single prey resource predicts that such a system will be stable only if the intermediate predator is better at exploiting the shared prey than the top predator, and the top predator also gains significantly from consumption of the intermediate predator (Borer et al., 2003; Holt and Polis, 1997; Krˇ ivan and Diehl, 2005). The examples of Palomares and Caro (1999) suggest that in some cases mammalian top predator species kill but rarely consume intermediate predator species, and there is no indication that any of these interactions are unstable. To begin reconciling theory to observation, we start by considering why some mammalian predators go to the trouble of killing other predators and then not consuming them. The answer is killing of competitors. Further: Exploitative competition may not be the only process by which killing a competitor is important, however— vigilance levels of both the intermediate predator and the shared prey may be affected. If individual prey are vigilant, eliminating the intermediate predator could benefit the top predator by indirectly relaxing vigilance in the shared prey. Additionally, if eliminating individual intermediate pre- dators makes others of that species more vigilant, and there is a tradeoff between vigilance and exploitative abilities, the intermediate predator may become a less efficient compe- titor for the prey, again benefiting the top predator. Prey vigilance has been observed to be important for predator–prey interactions in a number of mammalian systems (FitzGibbon, 1989, 1990; Hunter and Skinner, 1998; Laundre et al., 2001). One consequence of prey vigilance is that prey have a reduced food intake rate because vigilance interferes with foraging (Fortin et al., 2004; Illius and FitzGibbon, 1994), but predators also have a reduced food intake rate due to the decrease in prey vulnerability (FitzGibbon, 1989). There is less direct evidence for top predator species inducing vigilance behavior in mammalian intermediate predator species. Durant (2000) found, however, that cheetahs listening to playbacks of lion vocalizations are much less likely to hunt after hearing the playback, and often move away from the area of the playback. Thus, vigilance by the intermediate predator to predation from a top predator may reduce its efficiency in hunting a shared prey species. Here is some example info on influence and types of vigilance behaviour, going beyond frequency of breaks to scan for predators: 1. Many studies have investigated why males and females segregate spatially in sexually dimorphic species. These studies have focused primarily on temperate zone ungulates in areas lacking intact predator communities, and few have directly assessed predation rates in different social environments. 2. Data on the movement, social affiliation, mortality and foraging of radio-collared African buffalo (Syncerus caffer) were collected from 2001-06 in the Kruger National Park, South Africa. 3. The vast majority of mortality events were due to lion (Panthera leo) predation, and the mortality hazard associated with being an adult male buffalo in a male-only 'bachelor' group was almost four times higher than for adult females in mixed herds. The mortality rates of adult males and females within mixed herds were not statistically different. Mortality sites of male and female buffalo were in areas of low visibility similar to those used by bachelor groups, while mixed herds tended to use more open habitats. 4. Males in bachelor groups ate similar or higher quality food (as indexed by percentage faecal nitrogen), and moved almost a third less distance per day compared with mixed herds. As a result, males in bachelor groups gained more body condition than did males in breeding herds. 5. Recent comparative analyses suggest the activity-budget hypothesis as a common underlying cause of social segregation. However, our intensive study, in an area with an intact predator community showed that male and female buffalo segregated by habitat and supported the predation-risk hypothesis. Male African buffalo appear to trade increased predation risk for additional energy gains in bachelor groups, which presumably leads to increased reproductive success. From here. Animal movements are very commonly linked to efforts to avoid predation risk. Examples are fairly easy to find. Back to the article on vigilance and intraguild predation. First it creates two models of a single prey species and two competing predators. Both are equally lethal to non-vigilant prey, but vigilance has a greater impact on the ability of the prey to avoid the top predator than to avoid the intermediate predator. In one model the vigilance of prey is made to be constant, and in the other it is vigilance of the intermediate predator. ![]() The top predator is unable to survive if it doesn't kill the intermediate predator. As a note, the article also contained another model, with two prey species. Trying to represent lions, cheetahs, Thomson's gazelle, and wildebeest the top predator was more effective at preying on one, and the intermediate predator a more effective predator than the other. Basically, compared to the above, they added a prey source the top predator is better at using than the intermediate. ![]() The important lesson here however is this: if a predator isn't as effective at catching and consuming the available prey than another, for it to be able to survive in the ecosystem it must also kill the other predators-to decrease the vigilance of the prey (which in the model decreased the difference in predatory ability between the two), increase vigilance of the predator (decreasing its predatory ability), as well as taking energy from the intermediate predator and giving some amount to the top (proportional to consumption rate in the graphs). How would Gorgosaurus compare to the other predators? Vigilance of prey would be much more effective at deterring Gorgosaurus predation than it would be at deterring any of the other mammalian predators. Gorgosaurus is far taller (especially compared to a crouching feline) and larger. Ignoring behavioral abilities and flexibility that could make differences. The lethality without influence of vigilance is also much loewr for Gorgosaurus for most prey animals. Gorgosaurus, while it would have been much better at the killing part, lags greatly in ability to catch prey. This goes beyond the running speed problem: separating out a members of a herd is not easy. Gorgosaurus would lag well behind the other predators in ability to catch most prey, putting it at a large disadvantage compared to them when it comes to lethality. The question is not whether gorgosaurus can, under certain circumstances, catch them at all-it is how it compares to the competition. Mammoths would be Gorgosaurus's best bet, but I wouldn't count on them being more effective predators on them than the likes of Homotherium (which were probably very effective predators of the young). Besides the problem of mammoth vigilance. Modern elephants can be extremely vigilant. In the book "Silent Thunder" the author Katy Payne, for example, recounts going on a trip to see the rare (heavily poached) desert elephants. During the week long journey they only saw two elephants: their guide pointed out, which they could see with their binocular, two elephants running away from them reaching their trunks into their mouths to draw up water from their stomachs and pouring it onto their backs to allow themselves to continue running in the heat. They recognized humans from a great distance away (remember: they needed binoculars) and immediately put extremely drastic effort into getting away. Elephants do not take risks (one problem is with people most elephants have know idea how dangerous we are-they see countless of us and get along fine, and then randomly someone with a gun shoots them all leaving no/few survivors to learn the lesson). They reproduce extremely slowly and late in their lives, and are adapted for not taking risks larger than what would allow them to live a very long one. Besides the life history of elephants being focused on avoiding risk/danger/death to live a long life at the cost of very low productivity, that last part is another problem: low productivity. Rabbits can support many predators, breeding very quickly-> a lot of rabbits that predators can kill and eat. Not the life history plan of an elephant, which can't support much mortality. Their focus is almost entirely on avoiding it. Not that rabbits aren't pretty good at avoiding it too-they're very fast and causing lots of trouble in places like Australia. So the question now is: how dangerous would Gorgosaurus be to the North American predators? Consider the vigilance shown by brown bears when they are aware they're being tracked (iffy with humans, due to how many of us their are that don't track them). Enos Mills tracking of the bear named "Old Timberline" is a great read, published in his book "The Grizzly" in the chapter "Trailing without a Gun" (old enough to be available in full on Google Books). Old Timberline becomes aware of his presence on page 127-and the bear's reaction to the circumstances truly demand respect. Well worth a read. I've also in the past posted the story of the Giefer Grizzly-a wild bear equipped with a radio collar sentenced to death, but managed to avoid all the professional hunters equipped with his frequency, countless traps, etc. In the end he was killed by a random bear hunter while in the safe haven of Canada (at one point in his life he learned that pursuit stops once he crosses the imaginary line separating the US and Canada)-one can't differentiate random civilians (who are no threat and a complete waste of time and energy to avoid) from random civilians with guns and a bear license. Bears are relatively larger brained, however the other carnivores (who are far closer to the bear than to Gorgosaurus) are also aided by speed, efficient locomotion, and (for some small ones) tree climbing or burrowing ability. What is the likelihood that they will let themselves be caught with any sort of regularity? It is likely that most predator species won't even need significant levels of vigilance to avoid predation. Wolves for example would have an easier time pestering gorgosaurus than they do bears (bears can rotate much more quickly, and wolves are more efficient and faster runners than both) and they do not make much of an effort at all to keep their distance-yet still suffer very few bear-caused mortalities. So, I've presented two methods of assessing the situation: a) Studies determining relationship between characteristics of introduced species and whether they succeed or fail to survive when introduced to a new environment. Result: extremely unlikely. b) Predator prey models that discuss circumstances needed for multiple competing species to coexist. Conclusion: unlikely. a) is of course better for predicting success than b) as a) attacks the problem directly (and if we tried b) on all the species used in the samples to produce the results of the studies falling under a) we wouldn't make predictions nearly as well because b) simply attacks a different problem than what we're discussing here), yet for some reason no other posters have given method a) much attention (or simply failed horribly at predicting the relative importance of the different factors). Yet, despite overwhelming evidence, because Gorgosaurus is cool most people vote for it as an animal better adapted to survive in today's environment than the modern animals whose much longer evolutionary histories have culminated to produce it.[/quote]But here's the thing. This topic is not about how likely the given scenario is, it's about what would happen if the given scenario took place. If i wanted to ask how probable the scenario is, i would've asked. |
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| Ursus arctos | Jul 20 2012, 03:27 AM Post #21 |
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Autotrophic Organism
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Okay, there is obviously a failure in communication between the two of us, and I suspect it is more on your end. |
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| Admantus | Jul 20 2012, 03:37 AM Post #22 |
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Herbivore
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Please, explain on how i might be misinterpreting your post. I thank you for the elaborate graphs and articles on animal behavior and predator/prey relationships, but how does that correlate with the discussion? Edited by Admantus, Jul 20 2012, 03:47 AM.
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| Ursus arctos | Jul 20 2012, 05:43 AM Post #23 |
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Autotrophic Organism
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....asked in a poll "Could Gorgosaurus survive in North America today?"
How likely is the scenario of them surviving?
Cool, thanks for the responses!
Hey, we're not talking about probability and likeliness! Wtf? Hey, we obviously agree so I don't know what your problem is:
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| coherentsheaf | Jul 20 2012, 06:26 AM Post #24 |
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Kleptoparasite
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Excelent posts, Ursus. |
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| Admantus | Jul 20 2012, 06:51 AM Post #25 |
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Herbivore
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So wtf are you trying to get at urso? Look if you don't like this topic or simply want to make fun of it, just close it instead of pulling up unneeded info and going on and on about how coolness> facts, realism, or whatever the hell you're doing.
Edited by Admantus, Jul 20 2012, 07:30 AM.
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| Superpredator | Jul 20 2012, 06:31 PM Post #26 |
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Apex Predator
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What are you doing? He's(Ursus) is simply stating that Gorgosaurus simply could not survive. New prey, new predators and new diseases. Please tell us how it would overcome these factors. |
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| Admantus | Jul 20 2012, 09:12 PM Post #27 |
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Herbivore
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Well, for one, there's always adapting to new diseases. And ursus isn't simply stating the frickin obvious. He's poking fun at this topic. |
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| Megafelis Fatalis | Jul 21 2012, 12:51 AM Post #28 |
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Carnivore
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Actually Saber Toothed Cats (Smilodon Fatalis) will Prey on Gorgosaurus look at the size of Gorgosaurus, it doesn't seem really big to beat a saber toothed cats pack. |
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| Admantus | Jul 21 2012, 01:00 AM Post #29 |
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Herbivore
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Are you sure about that? Predators don't usually prey on other predators. And i know you greatly underestimate theropods, but a pack of saber tooths would be frightened of a creature like gorgosaurus. In fact, gorgosaurus may have hunted in packs. |
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| SpinoInWonderland | Jul 21 2012, 01:33 AM Post #30 |
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The madness has come back...
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smilodon fatalis is gorgosaurus food, you need smilodon populator and even then it's chances of victory are very low and prove that sabertoothed cats hunt in packs Edited by SpinoInWonderland, Jul 21 2012, 01:34 AM.
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