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Modern Weights and Measurements of Wild Lions
Modern Weights and Measurements of Wild Lions
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Modern Weights and Measurements of Wild Lions
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 (03-28-2022, 08:51 PM)GuateGojira Wrote:(03-28-2022, 02:54 AM)LoveAnimals Wrote: @GuateGojira The note that LoveAnimals included indicates that it was an intentional choice by whoever wrote those down, not really an error. It looks like they wanted to see how recent weights reported in various parks compare with the large Smuts dataset (Smuts being the standard accepted as reliable in many scientific publications). Of course, gathering examples together from multiple small samples has many caveats compared to a big sample directly weighed by one team of scientists, because unlike in the latter case there’s no consistent standardisation - you don’t know if the people reporting the data followed the same procedures, whether they had the same quality of scales, and so on… (That said, that overall range isn’t really anything out of the ordinary - males do tend to range between 170-250kg, with some exceptions on either side. The biggest difference is that it is skewed to the right - published samples tend to be skewed more to the left, averaging at about 190kg.)  (03-30-2022, 03:44 AM)LandSeaLion Wrote: The note that LoveAnimals included indicates that it was an intentional choice by whoever wrote those down, not really an error. It looks like they wanted to see how recent weights reported in various parks compare with the large Smuts dataset (Smuts being the standard accepted as reliable in many scientific publications). Normally I am agree with you, but not this time, not entirely. There are errors, but I suspect that are intencional, there are incorrect values included, estimations and young specimens included just because they are big. Like I say, I will provide an analisys about this information and will also provide more information about who made these calculations. 
I would like to move on from this circular debate.Settle any disputes in private messaging.
 (04-05-2022, 06:56 AM)Lycaon Wrote: Thread is closed. And Yusuf is out. This thread was created to collect reliable information about the length and weight of wild lions. Not something else. Thread will be cleaned by Lycaon. Lycaon, by the way, has been promoted to global mod. He now is responsible for all lion and tiger threads. Next time you see trouble coming in lion or tiger country, contact him right away. 
I asked about this male who was said to be 220kg
Marnus works at EWT with Constant, unfortunately they don't actually weigh their cats, just estimate.  *This image is copyright of its original author Hopefully he gets back to me in regards to how they estimate and with some body dimensions, but we'll see. I'm trying to contact the actual vets involved as well and will advise if I get anything. 
CHEST CIRCUMFERENCE OF NGORONGORO CRATER LIONS.
From Dr. Craig Packer, we have following two equations for estimating weight of lions using their chest circumference - First equation is based on Dr. Bertram et al. 1975 (Weights and measures of lions from Serengeti) and the second one comes from Smithsonian (as told by Dr. Packer). Correct me if I'm wrong, it is unsure which one was implemented in the research study of Dr. Brown et al. 1991. We also have two ranges for chest circumference of lions from this area. First one is 127 - 134 cm (apparently this was the range included in Dr. Brown et al. 1991) and second one is 120 - 143 cm which was told by Dr. Packer recently. It may also be possible that the range from 1991 research study is a misprint, as to my knowledge there hasn't been any other research on crater lions since then and the research study has other misprints too (eg. - the equation mentioned). The total range may be 120 - 143 cm only. From the second range, we know the exact value of chest circumference of 5 largest lions - 134.5 cm, 135 cm, 136 cm, 138 cm and 143 cm. These are large but nothing exceptional. This has been reached by lions from other regions too eg. 148 cm (Namibia) and 139 cm (Rhodesia / Zimbabwe). Value of smaller ones (under 130 cm) is unknown. So if one tries to calculate the mean from available individuals (n = 8) the result will be 133.4 cm which is false, leaning to the higher side. Other way one can try to find the mean is through using the estimated mean weight from Dr. Brown et al. 1991, which was 212 kg (n = 6) adult lions and then reversing the equations provided by Dr. Packer. 1. Using equation 1 a. When implementing the estimated weight of 212 kg, we get a mean chest circumference of 126.3 cm. - This is only possible if the range was 120 - 143 cm. In the other smaller range, the smallest value was 127 cm which alone makes the mean of 126.3 cm impossible. 2. Using equation 2 a. When we implement the estimated weight of 212 kg here, we get a mean chest circumference of 127.7 cm. - This is possible only in the case that 5 out of 6 lions in the range of 127 - 134 cm had chest circumference of 127 cm which is highly unlikely. b. Assuming that lions of 120 cm, 134.5 cm, 135 cm, 136 cm, 138 cm and 143 cm were NOT included, the final is 131 cm (n = 12). This is again not the proper result as the chest circumference of smaller lions is unknown. Conclusion - The lions used in Dr. Brown et al. 1991 most likely already include all the lions ranging from 120 - 143 cm. Based on the regression equation used, mean chest circumference of lions from Ngorongoro Crater is 126.3 - 127.7 cm (n = 6-12+) and up to 131 cm (n = 12). 131 cm is based on the assumption that larger lions aren't already included in the 1991 research study, and is not the proper result as it is based on larger individual lions. Hence the proper value will be lesser than 130 cm. This is negligibly larger than lions from other region (difference of only 1-3 cm). (04-12-2022, 11:37 AM)Khan85 Wrote: Conclusion - I think that 127 cm is a reliable average for the chest girth of male lions in Ngorongoro.
I was revising the calculations I did for crater lions.
In the paper of 1991, Dr. Brown used the chest regression equation by U.S. Seal which was as following :- (y = 1.84x - 189.11) where x = chest circumference and y = weight. This equation as given in the research paper is wrong, which I assume you people know by now. The problem I think is in the last part (189.11). To try and figure out the correct number, I did the most obvious correction: move the decimal point. y = 1.84x - 18.91 Instead of 189.11, I used 18.91. The results were better, much better. Now for a weight of 212 kg, I was getting chest circumference as 125.5 cm vs 12.44 which we would get using the wrong formula. But, if you remember, apparently the range of chest circumference of lions measured for the 1991 paper was 127-134 cm (n = 6). So this would mean if the range was indeed 127-134 cm, mean of 125.5 cm is false. But I haven't seen any source or evidence that said the chest circumference of the six measured lions were 127-134 cm. @GuateGojira @peter since you guys were there when the discussion on size of crater lions first started nearly 10 yrs ago, do you know from where was the range of 127-134 cm chest circumference of crater lions sourced? That would be really helpful. (05-12-2022, 07:57 PM)Khan85 Wrote: I was revising the calculations I did for crater lions. That range of 127-134 cm came from an old email of Dr Packer and do not have any sample size or any extra detail, it only says that the chest girts were between those numbers. However a personal email to me, from Dr Packer, says that the actual range of chest girths for male lions in the Crater is between 120 - 143 cm, but do not specify the sample size, average of any other detail. (05-12-2022, 10:09 PM)GuateGojira Wrote:(05-12-2022, 07:57 PM)Khan85 Wrote: I was revising the calculations I did for crater lions. In a recent email Dr. Packer says "around 8 males" and 5 of which were 134.5 cm, 135 cm, 136 cm, 137 cm and 143 cm. (05-12-2022, 11:44 PM)Khan85 Wrote: In a recent email Dr. Packer says "around 8 males" and 5 of which were 134.5 cm, 135 cm, 136 cm, 137 cm and 143 cm. Interesting. I will like to read the paper of Dr Yamaguchi, as Dr Packer says that he mentioned those males, sadly the paper is in Japanese and while I am using Google translate to read it, I still don't reach the part of the Crater lions. (05-13-2022, 02:07 AM)GuateGojira Wrote:(05-12-2022, 11:44 PM)Khan85 Wrote: In a recent email Dr. Packer says "around 8 males" and 5 of which were 134.5 cm, 135 cm, 136 cm, 137 cm and 143 cm. Can you tell me the name of the paper? I'd also try to read it. If it's the paper comparing sizes of lions and tigers, then I already tried my luck with that. Vertical writing makes it almost impossible to translate properly.
Chest circumference of Ngorongoro Crater Lions - Part 2
A simple regression done by me, on lions measured in Dr. Bertram et al. 1975a has cleared almost everything. Following were the results - The equation I got was: y = 3.6117x - 261.56 (where y = weight of the lion in kg and x = chest circumference of the lion in cm) Now, if you put y = 212 kg (as was obtained in the 1991 research paper), we get x = 131.1 cm Mean chest circumference of lions from Ngorongoro crater at 131.1 cm (weight = 212 kg) falls right in the range of 127 - 134 cm as told by Dr. Packer years ago. BINGO! Other lions we have are - 5 large lions: 134.5 cm, 135 cm, 136 cm, 137 cm and 143 cm; one smaller lion: 120 cm and the 6 young adult lions with mean chest circumference = 127.79 cm (using the same equation; weight = 200 kg). We get total mean chest circumference for crater lions (>4 yrs of age) as 131.05 cm (n = 18) and a range of 120 - 143 cm. Hope this clears up the confusions we were having while implementing other equations. Let me know what you think! |
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