Because most (if not all) mammals are diploid. "Allister MacDonald" <allisterm at ns.sympatico.ca> schrieb im Newsbeitrag news:3ACB89D1.A367C5F3 at ns.sympatico.ca... > hi i am wondering why all mammals have an even number of chromosomes, if > u have any ideas please e-mail me back, thanks > > ---