The mother replies, "Well son, when we trek across the desert your toes will help you to stay on top of the soft sand".
"OK" said the son. A few minutes later the son asks, "Mom, why have I got these great long eyelashes?"
"They are there to keep the sand out of your eyes on the trips through the desert", the camel mother answers.
"Thanks Mom" replies the son. After a short while, the son returns and asks, "Mom, why have I got these great big humps on my back??"
The mother, now a little impatient with the boy replies, "They are there to help us store water for our long treks across the desert, so we can go without drinking for long periods."
"That's great mom, so we have huge feet to stop us sinking, and long eyelashes to keep the sand from our eyes and these humps to store water, but... Mom?"
"Yes son?"
"Why the heck are we in the San Diego zoo?"
