Alpacas become sexually mature at 18months and that’s when Roy will start to rage. Castration can help but every single thing I’ve read about alpacas and especially the male berserk syndrome says the biggest way to prevent it is to not treat them like pets and do not over socialise them.
This was taken from a website.
What Is It?
Often referred to as Berserk Male Syndrome, and more recently referred to as Aberrant Behavior Syndrome (ABS), this is aggressive, un-mannerly behavior, and possibly will lead to extremely dangerous behavior in llamas and alpacas. Symptoms seen in a young animal may be jumping or rearing up, pushing against you, pulling on your clothes, getting in your face, being overly friendly and following you around trying to be very close to you, orgleing, or flipping their tail up over their back and dropping into a U-neck position when around people. This type of behavior, although it seems very innocent and perhaps cute when the animal is very young, becomes extremely dangerous as the animal matures - especially as he develops into breeding age and becomes territorial. There are many, many stories of owners suddenly finding their animals wildly charging at them from behind or rearing up at them screaming, spitting, and biting. It may happen with no warning whatsoever. Just one day as you're routinely bent over filling the water bucket, the animal comes charging from behind and smashes you to the ground. From there he may continue to stomp, bite, and scream viciously. Definitely scary, you'll consider yourself very lucky if you have no injuries.
Absolutely terrifying!!