Screaming and neck wrestling are behaviors alpaca males display when trying to establish dominance. They try to bite testicles and run at break-neck speeds around the pastures.
We have two fawn colored alpacas that are six months apart in age. Guy is older than Lucky. When they were young, they got along just fine. When Guys' testosterone kicked in things began to change between the two alpacas.
Guy is bigger and appeared to be more aggressive. We would always see Guy chasing Lucky and assumed that he always started the fight. One day we observed Lucky start the fight. We think Guy just always got the upper hand because he is larger.
Two pastures exist that out four male alpacas can go back and forth between. We would see Lucky in one pasture and Guy in the other. Guy would get this murderous look in his eye, tear off across the pasture and into the next, and attack Lucky. The fight was on!
When two alpaca males fight, they are oblivious to everything including their safety. They would run at break-neck speeds and scare us to death. We worried that one would be badly injured.
The fighting got progressively worse and the rest of the herd acted uneasy. Guy and Lucky would run and scream until exhausted. Guys' fighting teeth were removed at spring shearing but Luckys' hadn't erupted enough to trim. Having Guys' teeth trimmed cut down on the blood but not the fighting.
During the peak heat in the summer, we became concerned that they would overheat themselves. Many times we turned the hose on them to break up a fight. This worked for a short time, but soon you would hear them screaming again. We kept hoping they would work it out and peace would reign. But the fighting continued and was constant.
We finally decided that this wasn't going to work itself out and separated Guy and Lucky. We put Guy by himself in the smaller pasture. For two days all he did was pace the fenceline between him and the other three male alpacas. He wouldn't eat.
Next we put Guy with our gelding into the larger pasture and Lucky and our youngest male in the smaller pasture and closed the gate between them. This arrangement seems to be working better.
Guy occasionally neck wrestles with the gelding but the gelding is a big alpaca and the fight doesn't last long.
Lucky fights with the younger male, but it's not as ferocious and doesn't last long either. Watch the video to see these guys going at it. The fight is a lot of noise but no real damage.
Our farm is small and the males do share a fenceline with the females. Right now we have to live with that arrangement.
In conclusion, here is what we have learned about male alpaca behavior and our suggestions:
Testosterone will make your boys fight.
The males will scream and bite each other.
Get everyones' fighting teeth trimmed.
Keep the girls out of site if you can.
Break up fights with water if you must break them up for safety. DO
NOT step between them as this is dangerous to you.
Boys will be boys and need to establish their dominance (pecking order) and most of the time they'll work it out on their own but sometimes not and you must separate them.
Our guess is that Guy and Lucky being close in age are going to keep vying for dominance. And maybe they just plain don't like each other. Be prepared to separate males if they just can't get along. It will make your herd happier not to have constant fighting going on around them.
Hope this helps you understand your alpaca males behavior and peace reigns as it does here now.