Well, as earlier posted, I had the Equine Dentist out yesterday to float 2 of my horses teeth. Upon looking in my mare's mouth he said.."Hm, thats odd."

She apparently has recently (within weeks) cut Canine teeth on her bottom jaw-both sides and he thinks she will cut canine teeth soon on her top. Which after reading all morning, is apparently pretty rare-I guess about 30% of mares. I have 2 other mares and they do not have these teeth. This mare is a Rocky Mountain/TWH cross and is about 4 1/2 to 5 yeas old, from what I can tell. She has no papers.  

While reading, I started noticing a pattern of behavior that people were reporting in their mares that have these teeth-Dominant, pushy, some aggressive, and some portraying Stallion-like behaviors.

My mare with these teeth is all listed except aggressive. She is #2 in the herd of 5 and runs the bottom 3 all over the field some days (1 mare, 2 geldings). I wouldn't call her the alpha-mare type though(she's still young and kind of goofy to watch, too smart for her own good, but dumb if you know what I mean) when compared to the alpha mare that we currently have (which was a broodmare and is a sweet but stern leader, smart, and a true watch-dog[horse] of sorts).  

We have always joked that my mare was a stallion trapped in a mares body (she nuzzles the other mares and does other "reproductive things" around them). Some asked about a correlation between these behaviors and a hormone imbalance, possibly a little heavy on the testosterone side. The dentist also echoed hormone imbalance and difficult to breed as she would not be as prone to "taking" the stud.

She's a very fun ride, holds herself proudly, but has a little fire under her. She does tend to get pushy, even with me, at times. If I don't go in the pasture for a couple days, she gets looks like "why are you in my pasture?" but is never aggressive. Most times, she's an absolute sweetheart, calls out at you when she sees you, first one to the fence, loves human interaction, and we've been on some hairy trail rides together and really have a good trust in one another. I really enjoy this horse, even though she can be a challenge-I actually enjoy the challenge. I'm one that prefers mares over geldings any day. I always chalked her behavior up to limited human interaction for the first 2 years of her life, but all of this hormone talk makes perfect sense.

I'm wondering if anyone has any additional insight? Maybe you breeders would know a little more or noticed specific behaviors?

She tends to "gum" her bit, but has only done it in the past couple months, never before. Is this just her teething?

(Her bit is an IMUS comfort bit, so theres really no direct mouth pressure for her to shy away from).

(Please leave the "sell her" comments out--not an option)

I wouldn't sell her based on her pecking order in a herd. Gosh, she is just 5 years old. Still young in mind and still in need of some reinforcement ground behavior training. I have found the a five year-old horse is like a teenager - they like to test the waters and your patience. Ha!

And yes, she is still developing teeth at five. It's nice that you had her teeth floated and this should help with the bit issues. Here is a good chart since you are interested in dentistry - http://www.cherokeeanimalclinic.com/equine_dentalhealth.htm

If she is doing what you ask and offers a great ride, that would satisify me. I have a very dominant mare that I have had since she was three (she is 8 now). Her and my dominant gelding never got a long.... And I mean NEVER. She has her own pasture with a gelding to boss and he has two mares for his harem.

There are drugs or herbal supplements you can give your mare to calm those hormones down or you could spay her since she is not registered and that would end the goofy mare behavior once and for all. My friend uses a herbal called magic mare with success as her mare can get cranky http://www.valleyvet.com/ct_detail.html?pgguid=4456ef9f-86c6-4a3e-8915-c7d19a9390dc -

A bloodtest will tell you if the hormone levels are ok. Just remember too that this time of the year mares are cycling pretty hard right now. All my mares are acting goofy and squirting/squating in front of my geldings. Wishful thinking on their part!