Features which make mammals as dominant and successful animals are
(i) The presence of an insulating and protective hairy exoskeleton.
(ii) They are warm blooded so have high rate of metabolism.
(iii) They are viviparous animals and show placentation and intrauterine development which increases the chances for survival of young ones.
(iv) They show high degree of parental care.
(v) They have more developed hearing efficiency due to the presence of pinna, three ear-ossicles and coiled cochlea in the ear.
(vi) They are able to speak through language.
(vii) They have good power of learning due to the presence of more developed brain.