java organism super class

public class Organism{

  public Integer lifespan;
  public int iq;
  public String species;

  // base class (super class)
  public Organism(int lifespan, int iq, String species){
    this.lifespan = lifespan;
    this.iq = iq;
    this.species = species;
  }

  public void summary(){
    System.out.println(this.lifespan + "," + this.iq + " " + this.species);
  }

  public void age(int n){
    if(n < 0) {
      this.species + " has perished.";
    } else{
      this.lifespan - n; // compiler: "error: not a statement"
    }

  }




}

https://en.wikipedia.org/wiki/Immutability

http://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html