• Wind Cave National Park - Two Worlds

    Wind Cave

    National Park South Dakota

Abstract - Maternal Investment in Sons and Daughters: Problems of Methodology

Green, Wendy C.H. and Berger, Joel. 1990. Maternal investment in sons and daughters: problems of methodology. Behavioral Ecology and Sociobiology 27. pp. 99-102.


The prediction that mothers should invest more in sons than daughters was briefly examined in American bison (Bison bison) by Wolff (1988). He concluded that (a) male calves suckle more than females, (b) cows that had previously produced sons were more likely to be baren, and (c) cows that had male calves became estrous later in the year than other cows. In this paper we present data from two long term studies at different sites to show that Wolff's conclusions are equivocal at best and difficult to reconcile with predictions of the hypothesis because of questionable methods and assumptions.

Did You Know?

Porcupine in tree

Porcupine babies are called porcupettes. When they are born they have 15,000 quills. Porcupettes are born in the spring and, lucky for mom, the quills are soft. They can climb trees within an hour of birth. More...