CZ:Ref:DOI:10.1098/rsbl.2008.0469

Isler, K. & C.P. Van Schaik (2009), "Why are there so few smart mammals (but so many smart birds)?", Biology Letters: in press, DOI:10.1098/rsbl.2008.0469 ^[e]

Builds on the expensive tissue hypothesis proposed by Aiello & Wheeler (1995) and provides evidence that the maximum rate of population increase, as defined by Cole (1954), is correlated negatively with brain size in mammals and birds, as long as parental care is not provided (and thus the energetic costs of feeding borne) by the mothers alone. Predicts that such allomaternal care increases the "maximum viable brain size" in a given family and that brain size evolution is strongly coupled to mass extinction events.