An Alternative to ST and AAT

Newington Reference Library (
Tue, 03 Dec 1996 16:13:17 +0000

>From Andrew Lewis

On 17 October 1996 I contributed an article titled An Alternative to
Savanna Theory and Aquatic Ape Theory.

The main points were:
1. As hominids evolved they became less and less restricted to one
2. They could have moved seasonally between different environments
(savanna, coastal and forest) to exploit the seasonal abundance of each.
3. They could have been found in different environments at the same time
(coastal as well as inland), but a coastal region including savanna and
rupestrine forest was a probable site of hominid evolution for most of
the past 5 million years.

On 17 October 1996 Holly Reeser replied:
€What East African sites are coastal? Off the top of my head I cannot
think of any coastal Australopithecine or early Homo coastal sites. And
how will you test this?€

On 18 Oct 96 Paul Crowley replied to Holly Reeser:
€For most of the past 10 million years sea levels were about 100 (one
hundred) metres lower. We're currently at the peak of an unusual warm
interglacial and sea levels are at a 20 million year high. Any East
African coastal Australopithecine sites are likely to be under a 100
metres of water.

So if hominids were essentially coastal animals (as I maintain) what we
will get is an extraordinarily distorted fossil record which will make
little sense. And what do we have -- well, an extraordinary fossil
record that makes little sense.€

I think that what Paul said was valid but there is one area of East
Africa where this is not necessarily true. The Middle Awash region of
Ethiopia has the Ethiopian escarpment to the West. This was dry land
throughout the last five million years. However, the area to the East
was once open sea, although now it consists of recently formed rocks
mainly of volcanic origin. The River Awash once flowed into the sea, and
its valley was forested.

1. In 1994 the remains of Australopithecus(Ardipithecus) ramidus were
found at the Aramis site in Middle Awash: they were dated at 4.4 million
years old.

2. In 1974 the remains of Australopithecus afarensis (Lucy) were found at
the Hadar site in Middle Awash: they were dated at 3 million years old

3. In 1976 the earliest remains of Homo sapiens were found at the Bodo
site in Middle Awash: they were dated at 0.4 million years old.

In addition to this:

1. Australopithecus ramidus has only been found in the Middle Awash.

2. Australopithecus afarensis has only ever been found in the Middle
Awash and Laetoli (Northern Tanzania).

3. Australopithecus africanus is the first hominid found in southern
Africa and was similar to Australopithecus afarensis but occurred later
at about 3 to 2 million years ago.

Australopithecus anamensis has only yet been found in the Lake Turkana
region and has been dated to 4.2 million years ago. The earliest
anatomically modern humans were found in the Omo region and at Klasies
River Mouth in South Africa and dated at about 125 thousand years old.
Lake Turkana and the Omo River which flows into it are close to the
Awash. It all fits a picture of a coastal hominid population, continuing
to evolve on the coast but some hominids colonising the interior via the
Rift Valley as the population expanded.

If my theory (the Multi Habitat Theory) is true then Australopithecus
ramidus and Australopithecus anamensis were only at the beginning of
their development of aquatic adaptations. This is the opposite of the
Aquatic Ape Theory which would say that they had already completed their
aquatic adaptation and were beginning the evolutionary U-turn which
brought them onto the savanna. The more I think of this the
less tenable it seems.

I have only just discovered that expired original articles are available
at sci.anthropology.paleo FAQ on WWW.