public class Mammal extends Animal {
	private int gestationPeriod;

	public Mammal() {
		gestationPeriod = 10;
		System.out.println("mammal constructor (0 parameters)");
	}

	public Mammal(int gestationPeriod) {
		this.gestationPeriod = gestationPeriod;
		System.out.println("mammal constructor (1 parameter)");
	}

	public Mammal(String species, String sound, int gestationPeriod) {
		super(species, sound);
		this.gestationPeriod = gestationPeriod;
		System.out.println("mammal constructor (3 parameters)");
	}

	public String toString() {
		String s = "";
		s += "gestation Period: " + gestationPeriod + ", ";
		s += super.toString();

		return s;
	}
}