Bioturbation traces are very common in the one coastal and 11 inland dune fields we have studied. These fields occur in a variety of geographic settings in both cold and warm climates. The burrowing behavior of selected invertebrates, particularly arthropods such as sand wasps, sand-treader camel crickets, wolf spiders, crane fly larvae, beetles, ants, and termites, is illustrated in the variety of burrows in dune fields. The burrows of arthropods are significant because their traces in Permian eolianites seem to be similar to their traces in modern dune fields, and arthropods represent approximately 75 percent of the entire animal kingdom. Bioturbation traces are recognizable and preserved in eolian sand that is cohesive, organism reinforced, or rapidly buried. Although some geologists are reluctant to associate bioturbation traces with eolianites, groups of invertebrates capable of burrowing in dunes are known to have occurred for at least 300 million years; and tracks and trails have been documented in Permian and younger eolianites.