The study is based on the demographic long-term data of the monkey mountain, which has been operated as a branch of the University of Vienna since 2019. In 27 years, 112 females gave birth to 281 young monkeys. Not a single monkey mother died during childbirth at the monkey mountain in Landskron. Probably, the pelvic girdle and pelvic floor muscles of macaques are much more flexible during birth than in humans.
Childbirth is always difficult for humans and in some cases even life-threatening for the mother or child. This is also because the head (with the brain) of humans has become much larger in evolution, but the pelvis could not widen accordingly. Otherwise, the upright gait and other advantages of being human would have had to take a back seat. An international team of researchers and midwives has now studied a species of monkeys with a head-to-pelvis ratio similar to that of humans. These are Japanese macaques, which belong to the family of macaques and live in a semi-natural environment at the monkey mountain near Burg Landskron in Carinthia.
The Head-Pelvis Ratio
The team describes in the journal PNAS that there are hardly any birth complications in these monkeys: Not a single mother died when giving birth to her monkey offspring. In humans, it’s different: In countries with poor medical care, up to 1.5 percent of mothers die during childbirth due to the unfavorable ratio of head size to pelvis. The study is based on the demographic long-term data of the monkey mountain, which has been operated as a branch of the University of Vienna since 2019 and attracts researchers from all over the world. The data on birth and death events go back decades. For this study, the period of 27 years was analyzed, during which 281 young animals were born from 112 females.
The monkey mountain is a popular destination. A lot of research is also conducted here, as the semi-natural conditions are unique for behavioral research.
One reason why childbirth works better in macaques than in humans is still not clear. Researchers suspect that monkeys (standing or squatting) give birth more easily because the pelvic girdle and pelvic floor muscles of macaques are much more flexible during birth.
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