There are different pronouns available to express third person plural subjects in Dutch which differ in several aspects. One of these pronouns, <i>hun </i>&#8216;them&#8217;, was originally an object form, and can thus be considered a <i>quirky </i>subject. Therefore, there is an alternation between two third person pronouns, one of which is in the nominative case and the other in the accusative/dative. This can be characterized as differential subject marking. The question then arises what triggers the alternation. I will argue that the successful rise of the object pronoun as a subject in Dutch can be attributed to an important property of this personal pronoun: it exclusively refers to animate individuals. Purely animacy-based differential subject marking is rare from a cross-linguistic perspective. In order to explain how this special type of differential subject marking came about in Dutch, it is compared with the alternation it originated from: a case of differential object marking in Dutch.