The word Eutheria is formed from the Greek word eu meaning nature and ther meaning mammal. Mammals that possess true immortality are called immortalized mammals or eutheria. They are spread throughout the world. Dr. Siddique Publications
(i) They are true immortal mammals. Their embryo consists of chorion and allantois.
(ii) Immortals provide nutrients during their flowering. The gestation period is long lasting.
(iii) Their embryos remain in the uterus for some time and give birth to mature neonates.
(iv) Mammary glands of female animals are highly developed. It contains nipples.
(v) Their vagina is one. The testes are located in the scrotal sac.
Example: Human (Homo sapiens), Shushuk (Platanista gangetica), mouse (Mus musculus), Rusa deer (Rusa unicolor), tiger (Panthera tigris), fruit bat (Pteropus giganteus).