Word of the day: altricial

The word of the day is altricial:

1. helpless at birth or hatching and requiring parental care for a period of time (opposed to precocial )

(http://dictionary.reference.com/browse/altricial)

"The classic anthropological hypothesis known as the 'obstetrical dilemma' is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution.  The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapted birth canal poses a problem for childbirth; the hominin 'solution' is to truncate gestation, resulting in an altricial neonate."

 - Holly M. Dunsworth et al., "Metabolic hypothesis for human altriciality", PNAS 109:15212 (September 18, 2012)