Former horse buddies suddenly enemies?

We just brought our horses home (yay!) and my mare has suddenly decided she doesn’t like my husband’s gelding! They were best buds (mutual grooming, etc). She’s been lunging and threatening to kick - never actually lands anything, and she definitely could as she is far more agile than he is. I’m not worried about him getting hurt, just a little baffled.

Our 3 (2 geldings, 1 mare) were all together with 1 other very dominant gelding and our 3 all got along. The mare was bottom of the totem pole, as she always has been with geldings. With other mares she’s either #1 or #2. It’s not a time of the month thing either as she turns all googly eyed over boys rather than the other way around. Even if she had decided she’s now #2 of the 3, I don’t see why she’d still be going after him a week later.

Has anyone else seen this friends to enemies thing? Any advice?

Is she coming into heat?

Other than that when horses behave like this it does not mean they are “enemies.” Rather it means something has shifted in the environment and/or herd that is causing the horses to reassess their social status…Dominant and submissive are not static qualities and are not stacked hierarchically even in a herd but are relations between individual horses that are always open to change.

Once the dominant gelding is gone both your mare and your gelding could be testing each other. You see her react but he might be pushing or provoking her.

I would also closely observe your management and environment. Are the horses forced into close proximity in a pen or corner? Are they competing for food?

Anyhow I would see this as a period of readjusting herd dynamics rather than the horses “hate” each other.


The boss horse is gone and there’s a power vacuum. Nature -and apparently your mare - abhors a vacuum…


They are definitely working out social hierarchy. I am just concerned because this is very unusual behavior for her, especially with a horse she knows. I have owned her for 8 years and have seen her turned out with over 30 different horses and she has only ever been this aggressive with 1 other horse (a totally psycho and socially stunted TB). The 3 of them are on 7 acres, all grass. Definitely more pronounced at feeding time (they are fed spaced along the fence) but she still harasses him out in the middle of the field if he wanders into her ‘bubble’, which appears to change diameter randomly.

Not coming into heat; like I said, she LOVES the boys when she’s in heat.

They will sort it out. Be careful at feeding.

You moved to a new place, you removed the boss horse, which completely changed the herd dynamics.

Now the fight is on for the dominant position and other ranks. They will work it out if you let them.

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Yep, the dynamics have changed. It will take some time as they sort it out again.

Probably not in this case, but be aware that pain issues can also cause this kind of behavior. I used to know when it was time for my gelding’s hocks to be injected when he started getting nasty with his companion.

Yes if they feel off they don’t want to be crowded.