Those that lost and died were riddled with holes as animals burrowed their nests into the rotting wood.
This "irregular" body form has evolved to allow the animals to burrow through sand or other soft materials.
It seem unlikely the animal has been burrowing vertical into the sediment.
Some animals burrow into the sand and feed on material deposited by the waves.
These long low earth mounds were constructed to allow the animals to burrow in what were otherwise thin soils.
However, this allows the sled to get a pretty good cross section of what animals burrow because most live near the sediment water interface.
The animals were burrowing underground now, which was smart.
What animal would burrow into the earth for the flesh of a human corpse?
Many animals also burrow to avoid predation and to live in the more stable sedimental environment.
This condition allows the animals to burrow with their teeth without getting dirt in their mouths.