<P> Birth is the act or process of bearing or bringing forth offspring . In mammals , the process is initiated by hormones which cause the muscular walls of the uterus to contract , expelling the fetus at a developmental stage when it is ready to feed and breathe . In some species the offspring is precocial and can move around almost immediately after birth but in others it is altricial and completely dependent on parenting . In marsupials , the fetus is born at a very immature stage after a short gestational period and develops further in its mother 's womb 's pouch . </P>
<P> Birth is the act or process of bearing or bringing forth offspring . In mammals , the process is initiated by hormones which cause the muscular walls of the uterus to contract , expelling the fetus at a developmental stage when it is ready to feed and breathe . In some species the offspring is precocial and can move around almost immediately after birth but in others it is altricial and completely dependent on parenting . In marsupials , the fetus is born at a very immature stage after a short gestational period and develops further in its mother 's womb 's pouch . </P>
animals that give birth to their young ones alive are called
animals that give birth to their young ones alive are called
mammals
mammals