Penetrating Radar has a vast range of applications: from geologic
mapping to concrete inspection. A recently emerging
application is that of biological investigations through this
non-invasive technique. Geophysical mapping of features such
as tree roots and turtle burrows have proved to be valuable
techniques for the understanding of these subsurface systems.
We present three case histories of GPR investigations pertaining to
animal burrows: cutter ants in Brazil, groundhogs in Michigan, and
groundhogs in Pennsylvania. Cutter ants (Atta spp.) in
Amazonian Brazil are known to construct burrows of nearly the same
dimensions as groundhogs as they excavate galleries for storage of
leaves on which they culture fungi at depths up to 7m. Burrows
of cutter ants can be hazardous for heavy equipment and may also
cause loss of circulation during mud rotary drilling. GPR
surveys were utilized to identify these burrows using the GSSI SIR
10 radar system with 100MHz and 500MHz antennae in 1994.
Groundhogs (Marmota monax), found throughout the United States, are
another animal that can cause unseen hazards, particularly for
equestrian facilities where a sudden collapse can cause severe
injuries to horses and riders. An indoor horse riding arena in
Michigan experienced difficulties with these rodents in 2008.
GPR surveys were performed using a GSSI SIR 10A+ radar system with
500MHz antennae. The surveys at this location clearly
demonstrate the usefulness of geophysical methods in mapping these
hazards. Additional GPR surveys of groundhog burrows were
performed in eastern Pennsylvania in 2011 to define mammalian burrow
complexity as it relates to the rock record and paleontology.
Three separate burrows were surveyed using a GSSI SIR 3000 radar
system with 400MHz and 900MHz antennae. These surveys were
combined with endoscopic investigations to confirm the
interpretation of the GPR results which show the consistent nature
of groundhog burrow geometry.