JavaScript - accessing private variables in prototype methods

gistfile1.js

var Animal = (function() {
    var heartRate;  //private variable available in prototype functions
    function Animal() {
        heartRate = 90;
        console.log('heart rate: ' + heartRate);
    };
    Animal.prototype = {
        constructor: Animal,
        doDance: function() {
            heartRate = 120;
            console.log('heart rate: ' + heartRate);
        }
    }
    return Animal;
})();
var Human = (function() {
    var isArmRaise;
    function Human() {
        isArmRaise = false
        Animal.prototype.constructor.call(this);//calling animal's constructor
        console.log('is arm raised: ' + isArmRaise);
    }
    function F() { }
    F.prototype = Animal.prototype;
    Human.prototype = new F(); //To avoid calling animal's constructor
    Human.prototype.constructor = Human;
    Human.prototype.doDance = function() {
        isArmRaise = true;
        Animal.prototype.doDance.call(this);
        console.log('is arm raised: ' + isArmRaise);
    }
    return Human;
})();
var h = new Human();
h.doDance();

gistfile2.js

var AnimalPrototype = (function () {
    var heartRate;  //private variable available in prototype functions

    return {
        constructor: function () {
            heartRate = 90;
            console.log('heart rate: ' + heartRate);
        },
        doDance: function () {
            heartRate = 120;
            console.log('heart rate: ' + heartRate);
        }
    }
})();

var HumanPrototype = (function () {
    var isArmRaise;

    var HumanPrototype = Object.create(AnimalPrototype)
    HumanPrototype.superclass = AnimalPrototype;
    HumanPrototype.constructor = function () {
        isArmRaise = false;
        HumanPrototype.superclass.constructor.call(this);
        console.log('is arm raised: ' + isArmRaise);
    }
    HumanPrototype.doDance = function () {
        isArmRaise = true;
        HumanPrototype.superclass.doDance.call(this);

        console.log('is arm raised: ' + isArmRaise);
    }
    return HumanPrototype;
})();

var h = Object.create(HumanPrototype);
h.constructor();
h.doDance();