Food
Gibbons are frugivores and prefer ripe, pulpy, and sugary fruits (Leighton 1986). While fruit makes up 50 to 60 percent of the gibbon diet, figs (a preferred food), leaves, twigs, shoots, flowers, and occasionally bird eggs and insects are also part of the gibbon diet (Islam and Feeroz 1992; Leighton 1986).
The gibbon food sources are evenly distributed in small, plentiful, scattered patches (Islam and Feeroz 1992). While the food sources are fairly reliable, relative amounts do vary according to the time of year, resulting in an increased amount of time spent feeding between October and April (Islam and Feeroz 1992). This also leads to increased food competition between groups during certain times of the year.
Photograph courtesy of S.P. Flannery <http://members.tripod.com/cacajao/index.html>
Feeding occurs most often in the morning, peaking around 6 a.m. and then later at 10 a.m. (Islam and Feeroz 1992). Gibbon groups feed together; if one member of the group begins to eat, the others usually begin to feed as well (Islam and Feeroz 1992). Islam and Feeroz (1992) suggest that a diet consisting mainly of fruit provides the amount of nutrition required for the everyday energy needs of the gibbon, while requiring the gibbon to input minimal effort into obtaining the fruit from its rich patches. For more images of gibbons feeding, click here.
Gibbons have been observed to share
food in captivity, but food sharing has not been observed frequently in
the wild (Nettelbeck 1997). Of
the instances
observed in the wild, most, if not all, are involuntary on the part
of the giver. The receiver usually begs, approaching the giver and
reaching
for
the food source until the giver passes the food source. This behavior
is almost always observed between an adult and an immature gibbon,
with the
adult always acting as the giver. Nettelbeck (1997) contributes the
more frequent instances of food sharing in captive gibbons to food
type and
availability differences in the wild.