Zebras don't get ulcers

Though their legs are small
in that garish black and white,
they graze and they stroll
until it's time for flight,
though it's a hostile world
you will not see them fret,
to waters they shall wander
alert in times of threat,
though lowly is their stature
within life's food chain,
they do not feel our worry
in sunshine or in rain,
though placid is their nature
they do not dwell on same,
no self filled insecurity
no reason to feel shame,
though meagre is their means
they do not worry so,
in living they discover
in adversity they grow,
though the lion may roar
causing them to run,
they bask in every moment
through rise and set of sun,
though their days are numbered
beneath a clear blue sky,
still zebras don't get ulcers
although I wonder why.