Question: I have a 2 year old Rocky Mountain filly. This might seem kind of gross but I was cleaning up the paddock that she was in, nature called and I had to have a pee. She sniffed the spot afterwards and then rolled in that area. What was she doing??? I have had this filly for a little over 8 weeks.

 Answer: While olfactory investigation of urine and feces from other horses is commonly associated with stallions, mares will also investigate such interesting substances. Stallions will often ritualistically investigate the urine and/or feces of other horses. A stallion will often proceed to urinate and/or defecate over the other urine or feces. Sometimes a stallion will roll in urine spots as well, but usually avoids rolling in manure spots. It is common for mares to investigate urine spots or feces as well. Your mare was performing a perfectly natural behavior in investigating the urine spot. She apparently found it interesting enough to roll in. There are several theories on why animals (including horses and dogs) like to roll in what we might think of as gross or icky stuff. It is possible that the animal is trying to mask its own scent, or that it is simply trying to communicate that it has found something interesting. Foals (particularly prior to weaning) will often investigate the urine and feces of their dam in particular, and often even eat the feces. While this may not sound beneficial, it has been proposed that the behavior could be beneficial in multiple ways. Ingestion of the feces could help the foal recognize its dam’s scent, or  could help populate the gastrointestinal tract with beneficial bacteria.