Naked Science Forum
General Science => Question of the Week => Topic started by: nudephil on 09/12/2020 12:11:50
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Our latest question of the week comes from listener Jordan:
Why do females produce eggs inside the body at body temperature, but males have to produce sperm outside the body at a lower temperature?
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Because male sperm dies or becomes weak at a warmer temperature that's why the balls as they say I don't no the medical term are outside the body.
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At this time, no-one really knows.
There are a variety of suggestions in Wikipedia:
- Birds and many mammals have internal testes, eg whales, elephants. Some mammals with internal testes have specialized blood flow to keep them cool.
- Enzymes work better at lower temperatures?
- Mammal ancestors were small and needed big testes, so they moved outside the body?
- They could be damaged by pressure changes inside the abdomen while running and jumping (but why not ovaries?)
- More DNA damage (mutations) occur at body temperature
https://en.wikipedia.org/wiki/Testicle#Location
This article suggests that sperm are activated by a sudden increase in temperature, such as occurs during insemination.
- For this trigger to work well, sperm need to be kept below body temperature.
See: https://blogs.scientificamerican.com/bering-in-mind/why-do-human-testicles-hang-like-that/
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Asked and answered on this week's show! You can find the answer here https://www.thenakedscientists.com/podcasts/question-week/why-are-sperm-made-below-body-temperature
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According to my understanding, I guess sperms are created or developed best at a lower temperature than the core. Therefore the so-called testicles are kept externally to keep sperm cells at a lower temperature since the internal is at a higher temperature.