We present a magnetotransport study of the low-carrier density ferromagnet EuB6. This semimetallic compound, which undergoes two ferromagnetic transitions at T1 = 15.3 K and Tc = 12.5 K, exhibits close to T1 a colossal magnetoresistivity (CMR). We quantitatively compare our data to recent theoretical work, which, however, fails to explain our observations. We attribute this disagreement with theory to the unique type of magnetic polaron formation in EuB6. © 2000 American Institute of Physics.