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That’s just a personal anecdote. Some babies never crawl at all and some toddlers don’t start walking until much later than 12 months. And your 2yo toddler is s

That’s just a personal anecdote. Some babies never crawl at all and some toddlers don’t start walking until much later than 12 months. And your 2yo toddler is still nothing compared to the mobility and world-awareness of a two-month-old fawn, which has already learned to recognize and outrun predators at this age. The fact that there’s such a spread for these otherwise extremely important life stages in humans shows a lack of maturity in their development compared to other mammals, not the inverse. Something is a little different about us.

jriot 9y ago
If we were to compares ourselves to actual animals. Personal anecdotes wouldn't matter as fatality rates would increase without modern comforts not afford to animals. The child doesn't crawl or start walking for another year, child would die as the parents wouldn't care for weak off-spring. It sounds harsh when discussing humans but the differences in development occur because our death rate is low compared to wild animals. Thus allowing weak genes to be passed e.g., not being able to crawl or walk for 3 years double or triple the normal would not be tolerated in the animal kingdom.
- Tenhundfeld 9y ago
  Not necessarily. It depends on why the offspring couldn't crawl or walk for longer. If it's associated with something that increases survival in mature members of the species, it might be tolerated, even selected for. For example, if the child is delayed in walking because more metabolic resources are being channeled to larger brain development, that could be a survival benefit. I use that example, because that's essentially the theory of what happened in humans, in comparison to chimpanzees. (Obviously not 1 child randomly taking 2x or 3x to develop, but a slow evolutionary process.) Chimps are relatively helpless when they are born too, relative to most species. They nurse for years, stay with parents for years, are totally reliant on them for survival, etc. But they are not so helpless as humans. It's estimated human gestation would have to be about 18 months for newborns to be at a comparable stage of cognitive development as newborn chimps. So, from this perspective, we do take 2x the time in comparison to chimps, and yet it was tolerated. I guess my overall point is that evolution is more complicated than how quickly an offspring can crawl or walk or be independent.

jriot 9y ago

If we were to compares ourselves to actual animals. Personal anecdotes wouldn't matter as fatality rates would increase without modern comforts not afford to animals. The child doesn't crawl or start walking for another year, child would die as the parents wouldn't care for weak off-spring. It sounds harsh when discussing humans but the differences in development occur because our death rate is low compared to wild animals. Thus allowing weak genes to be passed e.g., not being able to crawl or walk for 3 years double or triple the normal would not be tolerated in the animal kingdom.

Tenhundfeld 9y ago
Not necessarily. It depends on why the offspring couldn't crawl or walk for longer. If it's associated with something that increases survival in mature members of the species, it might be tolerated, even selected for. For example, if the child is delayed in walking because more metabolic resources are being channeled to larger brain development, that could be a survival benefit. I use that example, because that's essentially the theory of what happened in humans, in comparison to chimpanzees. (Obviously not 1 child randomly taking 2x or 3x to develop, but a slow evolutionary process.) Chimps are relatively helpless when they are born too, relative to most species. They nurse for years, stay with parents for years, are totally reliant on them for survival, etc. But they are not so helpless as humans. It's estimated human gestation would have to be about 18 months for newborns to be at a comparable stage of cognitive development as newborn chimps. So, from this perspective, we do take 2x the time in comparison to chimps, and yet it was tolerated. I guess my overall point is that evolution is more complicated than how quickly an offspring can crawl or walk or be independent.