Monkeys make horrible pets (as well marmosets for the reasons to follow). If you ask me they are worse than hyenas or wolfes. Why? Besides the obvious inpredictable behavior, agressive disposision, huge canines and a increadle strength, there are more to this. Monkeys have to be the most hazardous animals regarding zoonoses. Hepatites, deadly strains of herpes virus, tuberculosis and many others miscelaneos virus and bacteria transmitable to humans are in the "menu". Nothing but bad stuff. Wolfes and hyenas can carry stuff too, but like dogs, ferrets and cats they can be vacinated against it and your safe regarding that. There isnt simply vacine against some of the things they carry. And that putting apart the need to satisfy the emocional needs of this very inteligent creatures. A huje outdoor space is a must as well as several animals to make a social group. If I wanted something really exotic I think I would get a gila monsterI would be safe from any zoonoses, and even if this is a venomous lizard, its practily harmeless compared with venomous snakes and many oter more exotic pets. Be warned that some exotic roedonts can also carry pretty nasty stuff