Why do alpacas spit?

The reason why alpacas spit is because alpacas are defending themselves.

Alpaca has no hard horns and sharp teeth to protect itself when it is in danger, so when it feels dangerous, it can only spit. If it feels that the warning is not strong enough, it will even carry out a second saliva attack. Its saliva is mainly composed of undigested forage, saliva and stomach acid, so some alpaca saliva will have a great smell.