Re: An alternative to ST and AAT
Gerrit Hanenburg (G.Hanenburg@inter.nl.net)
Tue, 03 Dec 1996 18:56:42 GMT
"John Waters" <firstname.lastname@example.org> wrote:
>>Female body weight H.erectus (African) is 52.3 kg.
>>Estimated age at first breeding is 14.2 years.
>JW: This is very interesting. I know that Paul has poured
>scorn on the utility of your calculations, so I wonder if I
>could ask whether the above figure is based on a single H.
>erectus fossil, or is a composite average of some kind?
The figure is an average based on KNM-ER 737,OH 28 and 34 femora.
>The figure implies a gestation period of ten months.
>Assuming that the actual gestation was nearly that of AMH,
>this also implies a post natal altricial period of four to
>six weeks. Perhaps more significant are the implications
>for the end of the period of hominid infantile development.
>The figure implies 4.5 to 5 years. This is LBI multi-age
>brood territory. What date are we talking about here?
At least 1.6 mya. (KNM-ER 737)
>According to the HBT (for what it's worth), the LBI brood
>would lead to an immediate change in the Response Seeker
>Characteristic. This would lead to the development of the
>typical HG multi-monogamic mating system, which in turn
>would lead to a reduction in sexual dimorphism. I wonder
>whether there is any evidence for this in later fossils?
The ratio male/female bodyweight in modern H.sapiens is 1.22.
If we use 63.0 kg for male bodyweight and 52.3 kg for female
bodyweight in African H.erectus (McHenry 1994) then the male/female
ratio is 1.20. In other words sexual dimorphism in early H.erectus was
similar to modern humans.
McHenry,H.M.(1994), Behavioral ecological implications of early
hominid body size. J.of Hum.Evol.27:77-87.