 A prime candidate for this role is what the zoologist Adolf Portmann labelled human “secondary altriciality”, a unique constellation of features of the human neonate relative to other primates: human neonates are, in their helplessness and possession of a relatively undeveloped brain, neurologically and behaviourally altricial, that is, in need of care. However they are also born with open and fully functioning sense organs, otherwise a mark of precocial species, in which neonates are able to fend for themselves (Portmann 1951: 44ff.). The facts that the human neonate brain is less than 30% of the size of the adult brain and that brain development after birth continues at the fetal rate for the first year (Walker &amp; Ruff 1993, 227) led the anthropologist Ashley Montagu to talk of “exterogestation” (Montagu 1961: 156). With these features in mind, Portmann characterised the care structures required by prolonged infant helplessness as the “social uterus” (Portmann 1967: 330). Finally, the fact that the rapid development of the infant brain takes place during a time in which the infant’s sense organs are open and functioning places an adaptive premium on learning that is unparalleled among organisms (Gould 1977: 401; cf. Stotz &amp; Griffiths 2018: 70).