  Hubble Space Telescope WFPC2 images of the Local Group dwarf galaxy Tucana
reveal an unbiased sample of distant field galaxies. While a large number of
these galaxies can be classified according to standard Hubble types, a
significant number of these galaxies can be identified as "ring" galaxies, a
morphology likely induced through galaxy collisions. We have identified seven
ring galaxy candidates in our fields. Assuming these galaxies lie between the
redshifts of 0.1 and 1 and that there has been no evolution in the galaxy
interaction rate, then the probability of finding a single ring galaxy in our
field of view is less than 1%. Alternatively, if the galaxy interaction rate
increases as (1 + z)**4.5, which represents a high-end estimate of the
dependence of the galaxy merger rate on redshift, the probability increases to
~10%. Thus, these observations provide support for a galaxy interaction rate
that increases steeply at moderate redshift. We also suggest several additional
factors that may play an important role in producing the relatively large
number of ring galaxies we have detected.
