Random number problems

Question

I'm creating a horse racing game and I'm having a problem with my random number generator inside my threads.
I'm creating four threads and then inside each of them I'm using:
sleep(rand.nextInt(5) * 300);
Which I thought would make each horse thread sleep for a different amount. Instead, my first horse thread sleeps for a random amount, then my next THREE threads sleep for the exact same amount!
Is my random (class random) object not being seeded properly or something?
What could be causing this?

Answer 1

Ok, here is a snipped version of my code:
public class HorseThread extends Thread {
private Random rand;
public void run() {
rand = new Random();
draw();
private void draw() {
// Grab the graphics object out of our JPanel
Graphics g = panel.getGraphics();
try {
for (int x=0; x < 500; x+=25) {
// Erase our racing lane
g.setColor(Color.WHITE);
g.fillRect(startX, startY, 500, 75);
// Draw our horse
g.drawImage(horsePicture, curX + x, curY, 75, 75, null);
// Sleep a random amount
int sleepamount = rand.nextInt(5) * 500;
System.out.println("Horse [" + horseNum + "] sleeping for [" + Integer.toString(sleepamount) + "] milliseconds.");
sleep(sleepamount);
} // end for
} catch (InterruptedException e) {
e.printStackTrace();
} // end try
} // end draw()
} // end HorseThread()