atomfullerene t1_iv02ftn wrote on November 4, 2022 at 8:02 AM

Reply to comment by [deleted] in How many children did Homo Erectus tend to have? by [deleted]

>They didn't have the dramatic gender dimorphism of humans

Hm? Humans have less sexual dimorphism than the other great apes, and H. erectus had more sexual dimorphism than humans (but not as much as other apes)

https://www.nature.com/articles/s41598-019-44060-2

>and were about half again as big as humans

H. erectus were larger than previous hominids but they weren't larger than modern humans! If anything they were marginally smaller.

>Did they have a monthly reproductive cycle like in humans or was it seasonal?

Very few primates have seasonal reproduction, so we can guess this is similar to humans and other primates

>How long did it take them to reach sexual maturity?

It's not entirely clear but H. erectus seems to have matured a little faster, or at least grown a little faster

https://royalsocietypublishing.org/doi/10.1098/rstb.2015.0234

> (humans reach this in about a dozen years though the ability to carry a child successfully and safely to term can take another few years)

Age of first birth tends to be around 19-20 in modern hunter gatherers. It's around 15 in chimps, so H. erectus was probably somewhere in the range between the two, though I couldn't find actual data for it

> homo erectus would likely have been able to have children faster than the 1 year average people tend towards.

This is not a realistic birth spacing, for humans or H. erectus. Hunter gatherers show a birth spacing of 3-4 years, and the other great apes have longer birth intervals. It's only in sedentary societies with abundant food and no need to carry offspring while foraging that humans can come close to a birth rate of 1 per year, and it's unusual even then. Actually producing 15-30 babies is even more unusual.

I wouldn't expect H. erectus to produce any more offspring than modern humans. Probably a bit fewer actually, considering the way modern humans displaced other hominids and seem to have had higher populations when they did so.

https://www.jstor.org/stable/10.1086/667591 table 1 has birth interval and age at first birth data

Cannie_Flippington t1_iv1d7oa wrote on November 4, 2022 at 3:32 PM

>Humans have less sexual dimorphism than the other great apes

Compared to H. Erectus, it's dramatic... at least until 2020. I see I'm behind the times.

>they weren't larger than modern humans

Where am I getting my science these days, smh...

>This is not a realistic birth spacing

It's not. I was unclear, I see. This is the average length of time between one birth and the conception of the next. Humans are physically capable of getting pregnant immediately after birth but unlikely to do so for roughly six months. Add in the six months it takes for the average length of time for conception and you've got a year. This was looking at the maximum number possible, rather than what's probable, because everything is pure speculation anyway.