From Newsgroup: sci.anthropology.paleo



https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2025.1473794/full
Front. Ecol. Evol., 09 June 2025
The behavioural ecology of hominin locomotion:
what can we learn from landscapes of fear and
primate terrestriality?

A defining feature of the hominin clade is
bipedality, often parcelled together with
terrestriality. However, there is increasing
evidence of locomotor diversity, both within the
hominin clade and amongst the Miocene apes that
came before them. There is also growing recognition
that bipedalism might have arboreal origins and that
arboreality persisted in several hominin taxa,
including our own genus Homo. Furthermore, the
difference between terms like rCLhabitualrCY and
rCLobligaterCY bipedality is not clearly defined and is
often inferred from fossil features, rather than a
description of each behaviour in vivo. Combining
fossil and palaeoecological evidence with insights
from behavioural ecology facilitates new
interpretations of evolutionary pathways and
highlights the importance of considering convergent
evolution in the emergence of locomotor traits and
characteristics. Taking such an approach also moves
away from assumptions of a straight-line trajectory
towards modern human locomotion and explores the
likelihood that independent forms of bipedality and
terrestriality arose at different times and in
different combinations with other features of ape
morphology and behaviour. Evidence from extant primate
species can broaden our understanding of the correlates,
causes, and consequences of terrestriality and can be
used to generate hypotheses which are then explored
further using paleontological methods. In this paper,
we explore the evolutionary origins of hominin
locomotion, but extend our review to include broader
timescales, a wider range of primate taxa, and an
integrated set of methods and disciplines for
generating and testing hypotheses about locomotion.
*Perceived risk (or, the rCLlandscape of fearrCY)* is a key
pressure that has selected for primate arboreality rCo
particularly nocturnal arboreality. We propose that
shifts in Plio-Pleistocene landscapes of fear rCo
caused by declining carnivoran abundance and diversity
rCo might also have been a key selection pressure in
changes to primate locomotion, particularly papionin
and hominid terrestriality. We discuss this hypothesis
and propose future research avenues to explore it
further. Not only will such research provide a more
nuanced view of the causes and consequences of a rare
behavioural trait in primates, but it could ultimately
help us explain how one group of African apes came to
spend all their time on the ground, and how that made
them human.

"Through this paper, we demonstrate that behavioural
ecology evidence indicates that the landscape of fear
might have been a key selection pressure shaping
primate locomotion. Rather than assuming that the
shared characteristic of terrestrial behaviour amongst
extant African apes was inherited directly from their
last common ancestor, we propose that the dramatic loss
in carnivore abundance and diversity over the past
three million years has allowed all African apes, as
well as many papionins, to become more terrestrial than
their ancestors, albeit with different styles of
locomotion. We propose integrated methods and particular
fossil sites and time periods that could broaden our
understanding of how localised fluctuations in predator
abundance or diversity might have facilitated the rise
of terrestriality in certain primate lineages. Not only
will this provide a more nuanced view of the causes and
consequences of a rare behavioural trait in primates,
but it could also help explain how one group of African
apes came to spend all their time on the ground, and
how that made them human."


'There has been a big focus on hominin bipedality as a
defining feature of our lineage. In this paper, we
summarise the trends that informed early theories about
the emergence of rCLobligate bipedalismrCY in hominins. We
extend our review to include broader timescales
(examining the primates and paleoenvironments of the
Miocene), a wider range of taxa (exploring the roots
and drivers of terrestriality across a broader set of
the primate order), and an integrated set of methods
and disciplines for generating and testing evolutionary
hypotheses (combining applied insights from behavioural
ecology with paleontology and paleoecology).
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