Formica obscuripes thatch mound nest.  A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate.

Sagehen Creek, California, USA
Formica obscuripes thatch mound nest.  A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate.

Sagehen Creek, California, USA
Formica obscuripes thatch mound nest. A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate.

Sagehen Creek, California, USA
Formica obscuripes thatch mound nest.  A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate.

Sagehen Creek, California, USA
Formica obscuripes thatch mound nest. A number of northern Formica species build mounds like these to capture thermal energy in an otherwise cold climate.

Sagehen Creek, California, USA
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all images and text © Alex Wild 2001-2013