How can I tell whether a creature uses Str or Dex to calculate its attack bonus?

@mikemearls @JeremyECrawford How can I tell whether a creature uses Str or Dex to calculate its attack bonus if the two are equal (Panther)

— Matt Petruzzelli (@mpetruzz) September 15, 2016

If the distinction is relevant, the DM decides. #DnD https://t.co/9tsA5HbgoZ

— Jeremy Crawford (@JeremyECrawford) September 15, 2016