Bucking when asked to canter

I have had my horse about 2 months and he just started bucking when asked to canter. Most of the time he just pins his ears but he sometimes bucks. What can I do to get him to stop pinning his ears and sometimes bucking? Thanks.

Sounds like a pain issue.

Does the saddle fit him properly? If you're not sure, I suggest conferring with a saddle fitter or a knowledgeable horsey friend who could help you with saddle fit.

I agree with strange. Its a pain issue.

How old is the horse, and how long has he been broken in?

What do you do when he bucks?

My horse does that sometimes and its not a pain issue, next time I would lunge him first both ways walk,trot,canter. If he is sound...ect then get one and do circles. If he doent want to trot or canter give him a flick of a whip. He could still be testing you

My mare would buck when not when worked out regularly--even if she was warmed up. Daily riding for a period and a couple years older and she is fine.

My horse is the same, if he isnt ridden regularly he acts like a moron

My mare does this. I finaly figued out that she doesn't like to have any lower leg on her when asked to canter.

I would rule out pain before just chalking it up to testing the rider. I would get your saddle checked first and if that's okay'd, I'd call a chiro. My mare did the same thing when I first got her and turns out her hip was out of place. A quick pop back in and she was loping like a champ.

There are too many variables here to give a good answer. Do you just ask for the canter? Or did you give your horse warning with a sitting trot first?
Does the saddle fit? Back pain? Does your horse do this on the lunge? How much free time does he get in a pasture?