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How were mammals able to reproduce; after the comet hit earth, with out a period of light?

Within the context of mammalian reproduction, the pineal gland depends on a complete photo period of light and darkness. So if the comet that caused a mass extinction blocked out the sunlight. How where mammals able to reproduce and lead the way for future mammals? Does that mean that there was primitive estrous cycle not present in mammals today?


  1. The mammals that survived may have been subterranean or underground living. Those mammals likely evolved to not need light to regulate breeding??

  2. There is no evidence that the comet blocked out all light. There is no evidence that all mammalian life was extinct. There is no evidence that a comet caused the extinction of the dinosaurs. Any more questions??

  3. Actually there is a lot of evidence that it WAS a comet that caused the extinction of dinosaurs. And I don’t think that’s your point.
    Well, I guess not all sunlight was blocked. The hit caused a coating of dust to cover the planer, but this doesn’t mean that earth didn’t receive any light. If that was true, ALL creatures would be extinct.
    Probably, those who survived were small ones without much need for light, they managed to get through with a little bit of it.

  4. “It has been estimated that after the collision there was so much dust in the atmosphere that the entire planet was completely dark for 1-3 months. The lack of sunlight would have caused the extinction of many plants and animals. Among the animals, cold-blooded forms like dinosaurs would have been affected more than the warm-blooded mammals.”
    This is from an awesome site – you should check it out.

  5. they used their sense of smell. most terrestrial mammals are nocturnal to decrease their likelihood of being killed by predators. if it’s sufficiently dark during daylight hours, there’s no reason for mammals to be inactive.

  6. Evolution would probably suggest that those mammals that had an easier time regulating their hormones without the sun would survive while those who didn’t died out. Pretty crappy answer, but that’s that.
    On a side note, it should be noted that mammals were nocturnal creatures at that time.
    On yet another side note, and somewhat unrelated: Mammals, when they evolved from reptiles, lost the ability to process the ultraviolet range as well as a series of colors due to this nocturnal behavior. Primates managed to recover some of that series of colors, but not the ability to see into the ultraviolet range. Birds, on the other hand, kept all the abilities from their reptilian (therapod dinosaur) ancestors.


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