How the donkey got it´s cross

I am not sure if you know that, but if you look at the back of a donkey(often called Christian donkeys), you will notice that there is a dark patch of hair that goes the length of its back, and another that crosses its shoulders. Legend has it that the donkey has worn this cross since the day it carried Jesus. These are the informations I found on the internet for you, pictures are taken in Corsica:
These markings are in the shape of a cross. Like the color traits of other animals (such as zebras), we don’t know exactly why these donkeys have this cross. But, it does show the wonderful variety among God’s creatures.
There is legend that the crosses on these donkeys appeared after Jesus rode one into Jerusalem (read Matthew 21:1-11). There is no evidence that this is true. The dark stripe in the form of a cross was a trait in these donkeys long before Jesus lived. However, the fact that Jesus rode a donkey into Jerusalem is very important. It fulfilled a prophecy that was spoken 500 years before Jesus lived, and showed He was the Messiah (read Matthew 21:5 and Zechariah 9:9).

Do all donkeys have a cross?
You may have heard the term 'Jerusalem donkeys' or 'Sicilian' used to indicate a gray-ish donkey with a cross and stripe over the shoulders and back. However, neither of these term are correct. Sicilian is a bloodline of small donkeys that can trace parentage back to the original animals imported from Sicily. MOST donkeys, regardless of color, and especially non-Mammoths, have a cross and stripe. Even some miniature donkeys that appear to be black actually have a faint cross and stripe. There may be some donkeys who do not have a cross, but the genetic marker has not been located to see where it is, or is not, and the breeding trial is highly complicated. So for now, the best answer to 'Do all donkeys have a cross' is, NOT VISUALLY.
Everyone knows that the donkey carries a cross on his back. Most people don't know the legend of the donkey's cross. The Story is told that the little donkey that had been Jesus' mount on Palm Sunday, came to the hill of Calvary. Seeing the tragic event occurring there he wished with all his heart he had been able to carry the cross for Jesus as he was the proper one to carry heavy burdens. The donkey turned his back on the sight, but he could not leave because he wished to stay until all was over because of his love for Jesus. In reward for the loyal and humble love of the little donkey the Lord caused the shadow of the cross to fall across his back and left it there for the donkey to carry forevermore as a sign that the love of God, no matter how humble carries a reward for all to see. It's also told that the leg stripes were received from walking through the palm branches that were laid in it's path in honor of the burden the donkey was carrying....

Hm, not quite sure about that story, but what I think is great, and it really shows that God is the creator and he is almighty, that whenever we look at a donkey we should be reminded, that Jesus was and is and is to COME! My prayer with everything going on in this world: Come soon Jesus! We are waiting in eager anticipation!