Which animal other than a mammal has four chambered heart and is warm blooded?
Birds are warm blooded and have a four chambered heart. All usual endotherms (birds and mammals) have 4 chambered hearts. Bird hearts have the same basic 4 chambers as mammal hearts, namely right and left atria and right and left ventricles. The presence of either feathers or hair would indicate the animal is one of the ones that is endothermic at all times because only birds and mammals fit this category.