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Size comparisons
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 (04-19-2022, 07:25 AM)Twico5 Wrote: I am not basing all of my statements off of two weights obviously because if I was then I would’ve started this convo by posting them. Do you have proof that belizean Jaguars are dwarfs? Maybe in a paper or something? You have no idea how the studies of prey base work, don't you? The example of the tiger that you put here shows your error. Using captive specimes is silly, as @Pckts also pointed out. They have different body plans and different metabolism, not even between the Panthera cats they are the same, imagin between a Panthera and an overgrow Felis. It seems that you don't understand hoy important is this point too. For example, a jaguar may be fee with 8 kg per day, and a puma with the same, but if they have different metabolist the jaguar may need more food than a puma of similar size, as they had more mass to sustain, or maybe is the contrary, the puma is more agile and the 8 kg that it eat is metaboliziced faster than the similar sized jaguar. As you can see, they are not the same, so can't compare captive animals even when they are feed the same. About the tigers, let me educate you how those figures work. First, the figure of 82 kg is not "low" as you may think, in fact even 6 kg for jaguars are not "low" as you want to show. You ignore how the scientists got these numers, don't you? You must learn that the scientists are not weighing every single animal preyed by the cats, that is imposible, they normally get the species preyed via scats (some times via kills) and then they calculate the percentage of consuption in relation with the other prey items (how ofter then kill animal "x" in relation with animal "y" and "z"). After that, the average weight is just estimated using 1/3 of the average weight of the females, for example if the female of a "x" species of deer weight 100 kg, then they will use 75 kg for the calculation with will represent the average weight of the species in the wild, including males/females/youngs, so is an average as a hole (in some documents the average for lions is 100 kg and tigers of 113 kg, to give you an idea). Then they use formulas to calculate the weight in relation with the percetage of consumption (based in numbers of prey hunted, not the actual food intake) and then they calculate the average weight. In the case of Pench, the figure of 82 kg shows that the average prey that tigers weight are about that size, showing a bias for prey of that size as is the most available in the area (certainly chital deer with had an average between 50 - 80 kg adult females and males). However these type of studies can only inform about the prey available, the selectivity of the predator and how often they hunt it in relation with population and density, but do not show how often they kill in relation with food consumption. In this case, the Pench tigers may hunt a prey of 82 kg every week to sustain they need (5 - 7 kg per day) so they cover the basics, but certainly that doesn't say how often they kill it and do not say if they kill bigger prey too. So, for a population of tigers with an average of 113 kg overall (males, females, subadults and cubs included), a random prey of 82 kg is more than enoght to sustain it, based in numbers, but certainly males hunt bigger prey than females, they have different huting rates and consumption, and sttudies like that of Dr Chundawat in Pann TR shows those variations. So no, you example of tigers is futile to explain your point of view. So, a jaguar with an average prey of 6 kg probaby will fill they needs killing one animal per day but latter killing a large pecari eery week to sustain. Scats analisys tend to overestimate small prey based in the hair present in the feces, that is why is good to compensate with killls. Also only kills overestimate large animals over the smalls. In that scenario jaguars in Belize are ok with that prey base, but you don't know how often they hunt it, there is where you fail, because you don't take in count the full spectrum of the situation, you just mention the numbers, but you don't have the backup to prove that pumas an jaguars had the same food consuption, or the same kiling rate, or the same food intake. Saying that Pantanal and Venezuela jaguars are "abnormal" is completelly false, as @Pckts and @"LoveAnimals" showed to you, the main prey base are wild animals. But prey base and food consumption is not all, as a Belize jaguar will not grow to the same size as Pantanal until several generations enjoyed the prey base, and the same with the Pantanal jaguars became like Belize in size. However, again, you see that the biggest pumas in Alberta, Washington or Chile, even with a good prey base and large prey items, they do not weight as the largest jaguars. About the Sonora jaguars and pumas, I don't see your point. If jaguars are killing cattle is obviously because they wild prey is low, that is a penomenon with any large cat (tiger, lions, leopards, etc). Meanwhile the pumas are better adapted for smaller prey and its consuption in cattle is smaller. Also, as I told you before, the bigger cat probably had more needs, so jaguars need to kill bigger prey to live and that is why they prefer cattle when is available, after all Hayward et al. (2016) explain this phenomenon as the jaguar evolved to kill bigger prey, not the prey that is living in America in these time. Pumas, on the other hand, evolved to kill small prey and is until now that bigger cats got extinct that they started to kill bigger prey. Two oposite situations, two completelly different body plans and two different metabolisms. The "countless" studies that you posted do not show that you pretend, for the contrary, only with the correct interpretation is that we manage to understand the full aspect and you can't use only the plan values if you don't have the other details that I mentioned you before. Is like the case of your comparative images, without real proof of the sex, age, health status and location, you can't actually compare the two species. I think that I am done with this, there is no point in this discussion. I will focus in the Smilodon issue, if it continue of course. |
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