Student Prize Award Abstract
1999 Poster Paper Award
THE IMPACT OF INFANT CARE ON SLEEP IN MARMOSETS (CALLITHRIX KUHLII):
IS LESS OR DISRUPTED SLEEP AN ADDITIONAL COST OF PROVIDING CARE TO INFANTS?
J. E. Fite and J. A. French Nebraska Behavioral Biology Group,
Department of Psychology, University of Nebraska at Omaha, Omaha, NE 68182-0274
Among primates, the immediate costs of providing care to dependent infants include the
energetic costs of lactation and infant transport, as well as effects on foraging and predator
avoidance. Evidence from human sleep studies, however, suggests that decreased time sleeping
and poor sleep quality is another potential cost of infant care. The purpose of this investigation,
therefore, was to determine whether marmoset (Callithrix kuhlii) parents with infants
spend less time sleeping, or exhibit disrupted sleep patterns, when providing care to infants.
Marmoset family groups were videotaped during the dark phase of the 12:12 light cycle.
We used a Sony 8mm HandyCam, and a JVC timelapse videocassette recorder to monitor parent
and infant activity, and a 250W infrared bulb provided illumination. Sleep and wakeful activity
were recorded from these records using instantaneous sampling techniques. Preliminary evidence
suggests that marmoset parents with infants spent less time sleeping throughout the night than
adults without young infants in the group. Further, adults with infants appeared to experience
more arousals from sleep than adults without infants. Additionally, mothers of infants appear
to spend less time sleeping and experience more arousals than fathers of infants. Our findings,
therefore, indicate that reduced time sleeping and sleep quality may be additional consequences
of providing infant care. Supported by NSF (IBN 97-23842).