Dinosaurs did not give birth and bears don't have a particularly big head to body ratio - the idea here is specifically that childbirth is hard and dangerous, not simply running around with a big head would be so.
As for the brain, I think having eyes close to mouth is useful to basically every animal, being able to hit food or enemies with the mouth accurately, and eyes came from brains.
Dinosaurs did not give birth
There no reason why species on other plants who are intelligent have to give birth. Yes, humans do but to be a great filter it would have to be true more universally.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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