Lots of human cells are constantly dying and being replaced. How different would a human-like creature be if most cells (excluding brain cells) had longer lifespans (5 times longer, or even more)?

As to how different, I mean in these regards:

  • General lifespan.
  • How much more (or less) they'd have to eat compared to humans.
  • How prone they'd be to disease compared to humans.

As for which kinds of cells, I'm thinking mostly on the lines of skin, muscle, bone, red and white blood cells, and some internal organs like lungs and heart.

Edit: I was also hoping that, while the cells of this species would take longer to die on their own, cells killed or damaged by external factors would be replaced just as quickly as ours. Would that be possible, or would this trait break the initial premise of the question?

  • $\begingroup$ How could a species evolve is both too broad and opinion based. You are topping it with an additional question, which is also really broad. Please, narrow it down to a single question which doesn't require a whole book to be answered. $\endgroup$
    – L.Dutch
    Sep 19, 2019 at 11:14
  • $\begingroup$ The lifespan of various kinds of cells varies very considerably. In what specific kind(s) of cells are you interested? $\endgroup$
    – AlexP
    Sep 19, 2019 at 12:05
  • $\begingroup$ @AlexP I informed those on an edit, I don't know if I can get more specific than that, but I'll try $\endgroup$ Sep 19, 2019 at 13:38

1 Answer 1


This process would backfire horribly. The dying and replacing of cells is actually how our body rejuvenates and heals. The process is fastest in areas prone to exposure to infection (thus why the mouth heals faster than anywhere else on the body, then the abdominal area, then our feet and hands). Moreover, some of our worst deaths come from cells being produced faster than they are eliminated (cancer) and thus growing in ways we shouldn't. Blood clotting is our cells dying and forming a corpse-wall that seals the wound. If this wasn't so fast, we would bleed out like poisoned rats.

The creature would probably eat less, but be very vulnerable to disease (as the longer-lived cells would naturally not be replaced as frequently, meaning any damage done by a foreign invader would last longer and thus cause more cascading damage, not to mention viral breeding cells would be more catastrophic). Life would likely be short and end very badly more often than not

Edit for the edit: With an accelerated "healing factor" (or how fast and strongly the body responds to external trauma), your creature would now be (depending on how extreme the accelerated process was) some rendition of wolverine EXCEPT viruses and cancers would still be extremely lethal to it. This is because cancer is the body over-producing cells and not registered as trauma by the body and viruses specifically use a cell's lifespan against the body especially immunodeficiency viruses.

  • $\begingroup$ That vulnerability to cancer and viruses actually seems to be a plus since I was afraid this species would be overpowered $\endgroup$ Sep 19, 2019 at 12:02
  • $\begingroup$ As for the healing speed, I think that human levels would be fine, only the cell's average lifespan would be longer $\endgroup$ Sep 19, 2019 at 12:04
  • $\begingroup$ @Aryton certain extrenal threats would still apply normally to it, such as neurotoxins (as they cause neurons to misfire or seize completely. This process would not register as trauma and, even if it did, the body's response would likely be localized to the wrong location. Also, necrotoxins would still function at close to full potency. The body might react quicker, but any tissue necrotized by the toxin would be irrecoverable and, unless the creature's healing factor includes a lizard like cellular memory for body part reconstruction, could only be covered with scar tissue. $\endgroup$
    – HA Harvey
    Sep 19, 2019 at 12:10

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