ABSTRAKOrangutan Asia?s great ape has relatively solitary style, which prevents a
mother for associating with two offspring. Since lactation is the most obvious
uniquely maternal service, weaning is often seen as the essential transition to the
ability to survive. However, the mother serves multiple functions: in addition to
nutrition, she provides transportation, shelter (against elements), and protection
(against conspecifics and predators), and demonstrates numerous skills that the
offspring can learn, including knowledge of food species (diet competence),
foraging techniques (foraging competence), and efficient use of the range (ranging
competence). The offspring eventually has to reach independence in all these
aspects, but does not necessarily do so at the same time for all of them (van
Noordwijk and van Schaik, 2005).
This study of two wild adolescence female orangutans (Kondor, 9.5 years
old and Milo, 7.5 years old) and their mother (Kerry with 31 year old second
offspring and Mindy with 24 year old second offspring) was conducted at
secondary forest the Tuanan Research Station, Central Kalimantan, Indonesia. To
describe their development of independence, data on their activity budget, nesting
behavior, ranging strategies and social interaction (distance intensity with mother,
feeding tolerance, and reproduction behavior) were collected during two periods
(December 2006 to May 2007 and September 2008 to September 2009). The
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behavior of a study animal was recorded using the instantaneous focal-animal
sampling technique and ad libitum for social interaction, while vertical methods
for nesting behavior, and GIS Arc View 3.3 for Day Journey Length (DHL) also
minimum convex polygon (MCP) for home range size.
The proportion of time spent in moving and social are higher with
adolescence females comparing their mother. The intensity of the distance
affects the process of nest building. It showed by the differences in the duration
of nest building and position of the nest. The day journey length and home ranges
of adolescence females are longer and larger compared with their own mother.
However, the overlapping still high (85-89%) and made them tend to spent
feeding tolerance often and longer with their own mother than other orangutans.
Larger home ranges lead the offspring having interaction with other orangutans,
especially with males. Sexual interactions (attempt copulation, intromission and
force copulation) between adolescence female orangutans more frequent
happened with unflanged males compared with flanged males.
