Moeskoker is used as a surname in the mid-1600s in Drenthe a province of the Netherlands. It is later abbreviated to Moes, at the time in this area the use of surnames was still developing so individuals in that era are sometimes recorded as Moeskoker, or Moes or identified by their patronyn only.
Currently the originator of the family is Jan Harms Moeskoker, some internet family trees identify Jan as having three sons but i have only shown one here on Geni as i have seen no evidence yet to connect the two other children.