错误C3867，不确定我需要做什么来修复

尝试编译下面的代码时，我收到一些错误c3867(

例如：

"错误 C3867： '动物：：睡眠'：函数调用缺少参数列表;使用"&Animal：：sleep"在第47行创建指向成员的指针，hammertime.sleep;

#include "stdafx.h"
#include <iostream>
#include <string>
using namespace std;
class Animal
{
protected:
    int age;
    string type;
public:
    void sleep() { cout << type << " : Sleeping" << endl; }
    void eat() {cout << type << " : Eating" << endl; }
    int getAge() { return age; }
    string getType() { return type; }
    Animal(int argAge) : age(argAge) {}
    Animal() : age(0),type("Animal") {}
    Animal::Animal(int, string);
};
class Lion : Animal
{
public:
    void sleep() { cout << "The lion is sleeping" << endl; }
};
class Hamster : Animal
{
public:
    void eat() { cout << "The hamster is eating" << endl; }
};
char YorN;
string aniType;
int eatOrSleep = 0;
int check = 0;

int main()
{
    Lion scar;
    scar.eat;
    Hamster hammertime;
    hammertime.sleep;
    cout << "Would you like to create a new animal? y/n" << endl;
    cin >> YorN;
    if (YorN == 'y' || YorN == 'Y'){
        cout << "What kind of animal?:" << endl;
        cin >> aniType;
        Animal newAnimal(0,aniType);
        cout << "Congratualtions, you just created a" << newAnimal.getType << endl;
        do
        {
            cout << "Enter either 1, 2 or 3:" << endl <<
                "1: Makes your animal sleep" << endl <<
                "2: Makes your animal eat" << endl <<
                "3: Exit the program" << endl;
            cin >> eatOrSleep;
            if (eatOrSleep == 1)
            {
                newAnimal.sleep;
            }
            else if (eatOrSleep == 2)
            {
                newAnimal.eat;
            }
            else if (eatOrSleep == 3)
            {
                check = 1;
                break;
            }
        } while (check == 0 );
    }
    return 0;
}