constructor-instance

function Mammal(name){										        //constructor
	this.name = name;
	this.offspring =[];
}

Mammal.prototype.sayHello = function(name){					//sayHello function
		return 'My name is' + this.name '!';
};

Mammal.prototype.haveBaby = function(){						  //haveBaby function
	var child = Object.create(Mammal.prototype);
	child.name = "Baby " + this.name;
	this.offspring = function(child){
		if(offspring[child] !== child){
			return this.offspring.push(child);
		}
	};
};

function Cat(name, color){									        //calls on prototype properties from instance of Mammal
	Mammal.call(this, name);	
	this.color = color;
}

Cat.prototype = Object.create(Mammal.prototype);			//prototype chain to Mammal instance

Cat.prototype.constructor = Cat; 							        //restores Cat function as constructor
  

Cat.prototype.haveBaby= function(color){					    //Cat specific haveBaby function
	var newCat = new Cat('Baby ' + this.name, color);
	this.offspring.push(newCat);
	return newCat;
};