Male Siberian ibex, a large and heavily built ibex living in Central Asia, are prone to group with community of the same sex with the increase of their age, Chinese scientists found in their study.

Male age plays an important role in this flocking behavior of the Siberian ibex. As males grow older, their segregation from females and younger males becomes stronger, the study showed.

"This behavior, social segregation as it is called, will reach maximum values for males of nine years old and older," said YANG Weikang, leading researcher of the study from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences.

Adult Siberian ibex males were socially segregated from females all year round, except during the rutting season, when female and male ibexes spend much more time in mixed-sex groups for mating, according to YANG.

The rutting season of Siberian ibexes in the central Tianshan Mountains, where the study was carried out, usually starts in October and ends in December.

"Our study clearly shows that social factors play a key role in the sexual segregation of Siberian ibexes," YANG said.

The Siberian ibex is a sexually dimorphic species, with females reaching their maximal growth around three years old, while males continue growing for six more years. Male Siberian ibexes have a slower growth rate than females; however, they will grow to two times larger and heavier than females in adulthood.

"Flocking with the same sex, age and size companions will guarantee the efficiency of their activities, due to similar body type and nutritional requirements. This may improve their chances of survival," said YANG.

Results of the study entitled "The effect of male age on patterns of sexual segregation in Siberian ibex" were published in Scientific Reports.