Why does this squirrel have a pierced ear?

Scientists do that, pierce squirrel ears

We also trap and mark squirrels to get a mark-and-resighting estimate of the size of the squirrel population. We put little ear-tags (like having pierced ears) and necklaces with colored beads on the squirrels in one 10-hectare area, and later look to see what proportion of the squirrels have markings. (This is similar to a mark-and-recapture study of goldfish crackers that can be done in the classroom to estimate the "population" of "goldfish"-- e-mail me when I go home if you want a copy of this lesson). These data on individual squirrels who have become friends over the years are interesting because we have learned that squirrels may live to be 10 years old, something biologists didn't suspect before, but that Greg and I guessed at a few years ago. This means that one very knowledgable mother squirrel might build up a whole inventory of information about a variety of food sources in her territory and raise lots of babies to succeed in her place. This is another reason why long-term studies are important to do.

http://rainforest.montclair.edu/pwebrf/rainforest/...

Squirrel Ears

im not a squirrel expert. but i'd say it was either a birth defect or an old wound that left a bad scar. why would anyone pierce a squirrels ear....if thats even possible...

all my squirrels have this, not defect nor tag...