Homo antecessor family picnic
at Happisburgh Beach 1 million BC. Image credit: Daily Mail
The peopling of the British Isles can be divided into two eras: post and pre the last glaciation. Whilst the evidence for the latter is fragmentary and somewhat sparse, sometimes wondrous things come to light.
The footprints in the Pleistocene
laminated silt beds on the foreshore at Happisburgh Beach uncovered by the sea
in 2013 are one such marvel. As the authors point out preserved footprints
pre-dating 40Ky are extremely rare. The location of the Happisburgh and other
sites with human footprints of this age is shown below:
Location of Happisburgh and other
sites with human footprints from Ashton 2014 (1). Original caption read: Figure
1. Map of Pleistocene footprint sites dating from prior to 40 ky in Africa and
Eurasia.
Once the site’s importance was
realised archaeologists moved quickly to record them before further erosion,
inevitably, destroyed them forever. The abstract of resultant paper (open
access and pdf download - yay!) by Ashton et. al. 2014 (1) is shown below:
Abstract
Investigations at Happisburgh,
UK, have revealed the oldest known hominin footprint surface outside Africa at
between ca. 1 million and 0.78 million years ago. The site has long been
recognised for the preservation of sediments containing Early
Pleistocene fauna and flora, but
since 2005 has also yielded humanly made flint artefacts, extending the record
of human occupation of northern Europe by at least 350,000 years. The sediments
consist of sands, gravels and laminated silts laid down by a large river within
the upper reaches of its estuary. In May 2013 extensive areas of the laminated
sediments were exposed on the foreshore. On the surface of one of the laminated
silt horizons a series of hollows was revealed in an area of
ca. 12m2. The surface
was recorded using multi-image photogrammetry which showed that the hollows are
distinctly elongated and the majority fall within the range of juvenile to
adult hominin foot sizes. In many cases the arch and front/back of the foot can
be identified and in one case the impression of toes can be seen. Using foot
length to stature ratios, the hominins are estimated to have been between ca.
0.93 and 1.73 m in height, suggestive of a group of mixed ages. The orientation
of the prints indicates movement in a southerly direction on mud-flats along
the river edge. Early Pleistocene human fossils are extremely rare in Europe,
with no evidence from the UK. The only known species in western Europe of a
similar age is Homo antecessor, whose
fossil remains have been found at Atapuerca, Spain. The foot sizes and
estimated stature of the hominins from Happisburgh fall within the range
derived from the fossil evidence of Homo
antecessor.
Based on previous research, on
the sedimentary sequence of the region, the team assigned the age of the
deposits to between ca. 1 million and 0.78 million years ago. They did so by
noting that the bounding layers were the Happisburgh Formation of date ca.
450ky. These overlay the estuarine sediments of the Hill House Formation (HHF)
of Early Pleistocene in age, dating to between 1 and 0.78 My. This in turn
overlies the Norwich Crag formation of earlier Pliocene-Pleistocene date.
Next the authors considered what natural
processes could have caused the extensive area of foot-shaped depressions. They
concluded, by reference to published literature that the depressions were in
fact fossil footprints made by mid-Pleistocene hominins.
So let’s look at these at these
ancient footprints!
Close-up of a single footprint at
Happisburgh, adapted from Ashton 2014 (1). Original caption reads: Figure 5b.
Detail of footprint surface. Photo: Martin Bates.
Of all the footprints uncovered
only one showed toes properly and that isn’t shown with any clarity in the
paper!
However as the team used the
laser-scanning technique multi-image photogrammetry (MIP) to record the surface
over the two weeks before it eroded. Dr Sarah Duffy of York University part of
the team that carried out the 3D image analysis, has provided some of the
images to Simon Parfitt of UCL (2), who was also part of the team that studied
the site. I have adjusted the contrast to show the toes:
At first I found it hard to
figure out what was going on.. the shape of the foot was just.. well.. wrong!
Then I recalled that I, and every other person in the western world have “wrong
feet”. It’s the wearing of shoes from an extremely early age that does it. A
study from the American Journal of Orthopaedic Surgery from 1905 show what our
feet should look like. The upper photographs show native barefoot populations from
the Philippines and Central Africa whilst the lower ones show a U.S.
businessman.
In the two photographs above, the
big and little toes spread naturally and fan out to provide a wide, stable base
for walking or standing. A line can be drawn that runs through the heel, ball,
and big toe of a habitually bare foot.
Below the habitually shod feet of
the businessman, also from 1905 show that no such line can be drawn, and the big
and little toes crowd to a point.
As depth of prints was
unavailable the authors chose to concentrate on the length and width of the
prints in their analysis. The foot lengths ranged from 50mm to ca. 325mm and
widths from ca. 50mm to ca. 150mm.
Using the multi-image
photogrammetry (MIP) data, the authors were able to deduce a number of
interesting facts from the 155 footprints on the surface. They were able to
infer routes of individuals across the area, the number of individuals as being
a minimum of 5, that male and female adults were present and that children were
amongst the group. Therefore they surmised that it was a family group and not a
hunting party.
Part of the authors’ quantitative
analysis looked at the 12 most clearly defined prints. These they plotted on a
length verses age graph, thus proving that at least 5 individuals of different
ages were present. See below:
Diagrams showing image of 12
clearest prints and the resultant length to age conversion from Ashton 2014
(1). Original caption reads:
Figure 8. Vertical image of Area A at
Happisburgh. a. Model of footprint surface generated from photogrammetric
survey showing the 12 prints used in the metrical analyses of footprint size;
b. Plot of length and width measurements of 12 prints showing possible
individuals. Means and standard deviations for foot length and age for modern
populations are also shown. doi:10.1371/journal.pone.0088329.g008
Based on a large body of research
that links foot length to height (the authors cited 7 papers from which they
drew their inferences), the authors were able to calculate the that the hominins
that made the footprints were between 0.93m and 1.73m tall, therefore further
confirming the presence of adults and children in the group.
Using both footprint area and footprint
length the authors were able to estimate the body mass of the adults in the
group. These ranged from as ca. 48-52kg using footprint area and 48-52kg using
footprint length.
By comparing such metric details
as staure, foot index and body mass available for the fossils from Sima de los
Huesos (the site of the type specimen of H.
antecessor), Neanderthal fossils from around European and anatomically
modern humans, the authors conclude that the closest match to species level was
Homo antecessor.
The data on the foot index is most instructive. According
to Klenerman and Wood (3), the foot of H.
antecessor is quite narrow and gracile with longer toe phalanges than later
hominins such as H. heidelburgensis,
H.neanderthalensis and some modern H.
sapiens populations. This could account for some of the longer narrower
footprints observed at Happisburgh. It is particularly pleasing that this
feature is accurately shown in the recreation of H. antecessor created by a Spanish museum.
H. antecessor showing gracile
foot. Image Credit: Ibeas Museum, Burgos, Spain.
I expect you’ve noticed the other
notably feature of the picture.. that would be the cannibalism.
A 2010 study of
the massive array of bones from Atapuerca found indisputable evidence of H. antecessor eating it’s own kind:
“Human cannibalism is currently recorded in abundant archaeological assemblages
of different chronologies. The TD6 level of Gran Dolina (Sierra de Atapuerca,
Burgos), at more than 800 ka, is the oldest case known at present. The analysis
of cranial and postcranial remains of Homo antecessor has established the
presence of various alterations of anthropic origin (cut marks and bone breakage)
related with exploitation of carcasses. The human remains do not show a specific
distribution, and they appeared mixed with lithic tools and bones of other
taxa. Both nonhuman and human remains show similar evidence of butchering
processes. The stratigraphic evidence and the new increment of the collection
of remains of Homo antecessor have led us to identify a succession of
cannibalism events in a dilated temporal sequence. These data suggest that
hunting strategies and human meat consumption were frequent and habitual
actions. The numerous evidences of cannibalism, the number of individuals,
their age profile, and the archaeostratigraphic distribution suggest that cannibalism
in TD6 was nutritional.”
It therefore seems that the rosy
picture painted by the artist of the picture at the top of this post, may not
have been a reflection of the true nature of Homo antecessor.
Yes it seems the British Press (the
source from which the artist’s impression is drawn) would have British Homo
antecessor was a kinder, more family orientated species than elsewhere in
Europe.
A good short video about the
discovery can be found here.
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