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25 Dec 2021	Mathchan is launched into public

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Why do Humans have descended testes but elephants don't ? Anonymous July 25, 2022 (Mon) 05:33:58 No. 5

>>6 >>9 >>11

- It is a well known fact that the main reason why testes in humans and most of the animals descend is to regulate the temperature of testes
- The functionality of sperms in temperature more than or equal to body is greatly reduced, the efficiency of sperms is so drastically reduced that artificial heating of testes is also been researched as a possible contraceptive methods
- Testes usually descend in the 7th - 8th month of gestation period due to the major influence of androgens (T) in the fetus, the condition in which the testes do not descend is known as "Cryptorchidism" which majorly affects the fertility of an individual

But, this behavior is not observed in mammals such as elephants, dolphins and whales
The case of aquatic mammals can be possibly ignored due to the fact that they live underwater hence they don't have to care much about the temperature regulation of their testes but what about elephants (https://www.publish.csiro.au/rd/pdf/srb03ab59)

(1/3)

Anonymous July 25, 2022 (Mon) 05:34:50 No. 6 >>7 >>9

File: 1657862520542s.jpg ( 1.73 KB , 125x89 , 1658727290944.jpg )

>>5
So, why didn't the testes of elephant descend ? don't they need to regulate the temp. of their testes too ? apparently not because some researches claim that their (Cetaceans like elephant, whales and dolphin) ancestors entered the waters 60 million years ago and hence were forced keep their testes in the intra abdominal cavity because physiologically testes are more sensitive to cold than hot
But then why didn't their testes evolved to descend unlike other mammals even if they have left their aquatic (cool) habitat a long time ago ? some researchers claim that their kidneys being closer to their intra abdominal testes helps the testes stay cool through the counter current mechanism of kidney [i cant find the study backing up tho :( ]
- But, so does the human fetus
- The testes of a human fetus descend in the 7th month of gestation and the kidneys are developed by the 2nd month
- This suggests that the undeveloped state of kidneys is not responsible for descending of testes in humans

(2/3)

Anonymous July 25, 2022 (Mon) 05:35:24 No. 7 >>8 >>9

File: 1657862651516s.jpg ( 1.76 KB , 108x125 , 1658727324347.jpg )

>>6
- Then why did the testes of humans descended in the first place ? duh huh its because of muh temp. regulation
- Then why didn't the testes of elephants descend ? because of muh aquatic ancestry
- But they left the aquatic ancestry a long time ago for much dryer habitats like deserts
- And as i stated above from that unfindable study, why tf did they develop a counter current mechanism around their testes if heat wasn't their first issue in the water itself as stated here (https://www.publish.csiro.au/rd/pdf/srb03ab59)
- Hippos who have much closer ancestry to aquatics have semi descended testes but they are almost 80% of the time in water so their need for low temp and habitat preference can justify their semi descended testes

(3/3)

Anonymous July 25, 2022 (Mon) 05:36:00 No. 8 >>9

File: 1657864026241s.jpg ( 2.38 KB , 95x125 , 1658727360825.jpg )

>>7
+ If we ignore the affects of temperature on fertility of an organism
1) Is there any evolutionary advantage / disadvantage of descended testes or presence of a scrotal sac ?
2) Is there any evolutionary advantage / disadvantage of non descended testes or absence of a scrotal sac ?

only one i can think of is that descended testes in scrotums can be easily damaged in some accident and the person can immediately lose his biological rights to being a father

Anonymous July 25, 2022 (Mon) 05:38:17 No. 9

File: IMG20211231164027.jpg ( 1.39 MB , 4000x3000 , 1658727496972.jpg )

>>5
>>6
>>7
>>8
i made this thread on /sci/ but got really vague and bs answers so i would like to ask Mchan's opinion on this

thread -->(https://warosu.org/sci/thread/S14661729#p14663812)

Anonymous July 28, 2022 (Thu) 13:23:50 No. 11 >>12

>>5
Why not make the comparison against other large herbivorous mammals that share their terrain like african buffalo instead of humans?

Anonymous July 30, 2022 (Sat) 03:36:45 No. 12

>>11
i took humans just for the sake of it and the difference between the morphology and physiology of buffalo testes and human testes is not that much so taking a buffalo won't be a bad idea but at the same time choosing humans also doesn't disapprove my arguments

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