Water Melon in the Desert?

in the middle of the dessert, i found this watermelon like fruits.
the size of, say, baseball.
from the outer texture, im sure this is water melon.
but how is it grown in such an extreme environment?
and what could it taste like?
could be sweet because of the density, or due to the lack of water, could be dry?
ummmm, should have tasted it...