[en] Resistivity (15 - 710 K), magnetization (80 - 723 K), and calorimetric (200 - 623 K) measurements on La_0.7Ca_0.3MnO₃ have shown evidence for the formation of Jahn - Teller (JT) polarons below ∼545 K. Above 560 K, activated conduction with E_a = 0.05 eV is observed and χ^-1(T) shows Curie - Weiss behaviour. Over the temperature range 270 - 340 K, the conductivity follows Mott's VRH model and χ^-1(T) provides evidence of the formation of spin clusters. Calorimetric study shows phase transitions at T_C (=245 K), 345 K and 545 K. The role of the JT polaron in determining the electronic and magnetic properties above T_C is discussed. (author). Letter-to-the-editor