H.erectus Out-of-Africa??Out-of-SE.Asia

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Pleistocene footprints show intensive use of lake margin habitats by Homo erectus groups
Neil Roach, Kevin Hatala, Kelly Ostrofsky & Brian G Richmond 2016
Scientific Reports 121(1) doi 10.1038/srep26374

Reconstructing hominin paleo-ecology is critical for understanding our ancestors’ diets, social organizations & interactions with other animals.
Most paleo-ecological models lack fine-scale resolution, due to
- fossil hominin scarcity &
- the time-averaged accumulation of faunal assemblages.

Here we present data from 481 fossil tracks from NW-Kenya, incl.97 hominin footprints attributed to H.erectus.
These tracks are found in multiple sedimentary layers spanning c 20 ky.
Taphonomic experiments show:
each of these trackways represents minutes to no more than a few days in the lives of the individuals moving across these paleo-landscapes.
The geology & associated vertebrate fauna place these tracks in a deltaic setting, near a lake-shore bordered by open grasslands.
Hominin footprints are disproportionately abundant in this lake-margin environment, relative to hominin skeletal fossil frequency in the same deposits.
Accounting for preservation bias, this abundance of hominin footprints indicates repeated use of lake-shore habitats by H.erectus.
Clusters of very large prints moving in the same direction further suggest:
these hominins traversed this lake-shore in multi-male groups.
Such reliance on near-water environments (& possibly aquatic-linked foods) may have influenced hominin foraging behavior and migratory routes across & out of Africa.
...
As the first hominin species to migrate out of Africa, H.erectus’ global expansion would have required moving through & surviving in inhospitable environments.
Consistent access to water would have allowed H.erectus to sweat effectively without dehydrating, increasing day range & mobility.
Near-water habitats such as lake-margins & rivers may have provided corridors for long-distance travel & migration (Joordens 2013, Verhaegen 2013).
These aquatic corridors would have made access to food & water more predictable, buffering hominins from climate change, particularly the increasingly arid conditions in N.Africa that our ancestors would have faced as they spread out of the continent.

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