Re: AAT reply from Elaine Morgan
David M woodcock (firstname.lastname@example.org)
28 Dec 1994 23:34:26 GMT
>>The proto-hominids survived; selection on the savanna favored improved
>>bipedalism. Several nonobvious factors favored survival. There were
>>fewer types of large carnivores on the savanna than there are today.
>>Very probably the modern big cats were absent; certainly
>>the canids were. Hyenas are night hunters. Thus foraging during
>>the day wasn't quite as dangerous as one might think.
>No big cats in Africa? I think you are mistaken. In fact, I think
>they were actually BIGGER than modern day cats. For example the
>"saper-toothed" tiger which fed on mammoths was larger than the modern
Nope I said "Very probably no modern big cats" when proto-hominids
emerged on savanna about 5-6 Ma ago.[from context of whole posting
it was clear I was using proto-hominid as ancestors of hominids and
African apes.] From my reading of the literature 12 years ago there
was no evidence of the modern lion in Africa prior to 2 Ma ;
my memory is not so clear on the leopard, but I think there was
none for it as well. However, big carnivore fossils are rare;
some may have turned up since then, hence my caveat.
As for the saber-toothed cats -- I was aware of them. But I doubt
they were as much a threat to hominids making forays onto
savanna as modern cats would've been. They were specialized for
big game, almost certainly were stalking/pouncing killers,
probably night hunters. Judging by Lucy's postcrania her ancestors
were in the trees at night.
>There is also a fairly famous example of a leopard tooth which fits
>quite snuggly into an early human skull.
Quite right -- but dating on this is uncertain last I read.
Indeed my source didnt say if this was africanus or robustus !
It could date between 2.5 - 1.5 Ma. And I was referring to ~5 Ma.
>And I would be very surprised if there were not canids in Africa as
>The modern day hunting dogs and jackels have ancestors which go back
>millions of years, certainly farther than human ancestors.
No the modern hunting dogs go no further back than the zebra.
Their ancestors came from Eurasia about the same time Equus
>Also, hyenas are very opportunistic. The will hunt at night, or in the
>late afternoon. It depends on the food supply.
Hyenas are most effective at night. They do scavenge by day.
However, day hunting --if it ever occurs -- is so rare that before
night hunting was discovered they were thought to be simply
scavengers; most big carnivores do both. The point was there was
an opportunity for a day forager who took refuge in the trees at
night [or late afternoon]
Of course, monkeys also rushed in to fill the niche, i.e.
the giant baboon.
>I would imagine that the savannha was a very dangerous place for our
>early ancestors. Certainly for a slow bipedial ape, with relatively
>poor earing (especially compared to other savanna creatures) and
>almost no sense of smell. While our eysight is good, it really is not
>much better than most carnavoirs, who can actually see much better in
>the dark than we can, and probably better than our early ancestors as
No. I did a lot of reading on human and mamallian perception
[as well as classes]. Human day vision is much superior; for one
thing its color; carnivores either have no or very poor color
vision. And its more acute. Carnivore vision is optimized for
low light -- thus not color, highly keyed to motion. During the
day better vision gave hominids an edge; at night I doubt they
stayed on the ground 5-3 Ma.
>This is one of the problems I have with the savanna theory happening
>early after our tree-dwelling stage. I think it is obvious that the
>savanna would be a very dangerous place for our slow ancestors, and
>our ancestors could only have ventured out onto the savannas after
>they had developed suffecient tool technology in order to protect
I doubt the slowness of our ancestors mattered very much as I
doubt they did much running from cursorial hunters. There are
two ways modern savanna monkeys cope with savanna carnivores;
they run for trees or they confront them with a screen of
younger males backed by the more formidable dominant males.
Leaf eaters run; baboons confront. Leaf eaters show little
sexual dimorphism; baboons exhibit a lot; A.afarensis was
highly sexual dimorphic. Note prey doesnt have to be as
formidable as a carnivore to dissuade it; no carnivore can
afford a lunch that will kill it about once every 2 months.
As for tools it doesn't require high tech to obtain a hand held
weapon as effective as a male baboon's fangs from the savanna.
Lots of pointed, edged bones at hyena kills. And pointed horns.
And crude wooden clubs require very little thought to make.
Factor in that pound for pound A.afarensis was much stronger
than modern humans and you see that several 'primitively' armed
males could dissuade a hyena pack -- probably the most dangerous
threat to hominids c. 5 Ma [btw these were giant hyenas if memory
Equipment that will deter a carnivore, e.g. a fang
that causes a nasty puncture wound that's likely to become
infected, may be inadequate for hunting --since not only
do you have to catch the prey you must reliably avoid its
predator deterence equipment.