Newborn babies are just 15 -- 18 cm ( 5.9 -- 7.1 in ) long ( including tail ) .
Newborn babies weigh about 0.5 g ( 0.018 oz ) .
Newborn babies are just 15 -- 18 cm ( 5.9 -- 7.1 in ) long ( including tail ) , and weigh about 0.5 g ( 0.018 oz ) .