..\animal.cpp:-1: ошибка: multiple definition of `Animal::_totalAnimal'

3 файла:

main.cpp

#include <iostream>
#include "animal.h"
using namespace std;
int main()
{
    cout << "Hello World!" << endl;
    return 0;
}

animal.h

#ifndef ANIMAL_H
#define ANIMAL_H
#include <string>
using namespace std;
class Animal
{
protected:
    string _name;
    int _age;
    bool _isMan;
    static int _totalAnimal;
public:
    Animal();
    Animal(string name, int age, bool isMan);
    Animal(const Animal & obj); // конструктор копирования
    ~Animal();
    void setName(string name);
    void setAge(int _age);
    void setMan(bool _isMan);
    string getName() const;
    int getAge() const;
    bool getMan() const;
    static int totalAnimal();
    virtual string get_type() const = 0;
    friend ostream& operator<<(ostream& os, const Animal& dt);
};
int Animal::_totalAnimal = 10;
#endif // ANIMAL_H

animal.cpp

#include "animal.h"

Animal::Animal() { Animal::_totalAnimal++; }
Animal::Animal(string name, int age, bool isMan) {
    Animal::_totalAnimal++;
    setName(name);
    setAge(age);
    setMan(isMan);
}
Animal::Animal(const Animal & obj) {
    _name = obj._name;
    _age = obj._age;
    _isMan = obj._isMan;
}
Animal::~Animal() {
    Animal::_totalAnimal--;
}
void Animal::setName(string name) {
    if (name != "")
        _name = name;
    else
        throw 1;
}
void Animal::setAge(int age) {
    if (age >= 0)
        _age = age;
    else
        throw 2;
}
void Animal::setMan(bool isMan) {
    _isMan = isMan;
}
string Animal::getName() const { return _name; }
int Animal::getAge() const { return _age; }
bool Animal::getMan() const { return _isMan; }
int Animal::totalAnimal() { return Animal::_totalAnimal; }

Выдает 3 ошибки:

C:\Users\q\Documents\QT Project\pesok\animal.cpp:-1: ошибка: multiple definition of `Animal::_totalAnimal'
C:\Users\q\Documents\QT Project\pesok\main.cpp:-1: first defined here
collect2.exe:-1: ошибка: error: ld returned 1 exit status

Еще кому интересно pro-файл в проекте QT:

TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG -= qt
SOURCES += main.cpp \
    animal.cpp
HEADERS += \
    animal.h