In any good relationship there is an element of protecting each other from harm in whatever form it takes. These zebras appear to do so literally.
The black and white stripes of the zebras are in stark contrast to a non-traditional multi-coloured rainbow.
Rainbows have meaning in many cultures. To name only a few:
In Genesis God purged the earth of evil by flooding the earth, sparing only what came with Noah on the ark. He sent a rainbow as a sign that He would never flood the earth again.
Greco-Roman and Norse mythologies view rainbows as a bridge between Heaven and Earth.
In Chinese mythology, the rainbow was a slit in the sky sealed using stones of five different colours.