Word макак can be directly produced from макака. No matter if dictionaries mention it or not, it is 100% understandable and mostly unambiguous. In Russian language, we constantly morph words to adapt its meaning. Макак can be used to express male animal, or mean, seriously-looking animal of any gender. For example, a monkey in dress, which is sipping tea from the cup and smoking pipe, would most likely be called "макак", while natural wild animal in the woods would be "макака", no matter of thier genders. And of cause such intrinsic details of language may vary from town to town.

The word макак can be directly produced from макака. No matter if dictionaries mention it or not, it is 100% understandable and mostly unambiguous. In the Russian language, we constantly morph words to adapt their meaning. Макак can be used to refer to a male animal, or mean, seriously-looking animal of any gender. For example, a monkey in dress, which is sipping tea from a cup and smoking a pipe, would most likely be called "макак", while a natural wild animal in the woods would be "макака", regardless of their gender.

And of cause such intrinsic details of language may vary from town to town.