allometric growth pattern and sexual dimorphism of skull on brown bear(ursus arctos linnaeus, 1758)of the alborz mountain

this study was conducted to investigate theallometric growth pattern and sexual dimorphism in the skull of both sexes ofiranian brown bear (ursus arctos) in thealborz mountains using geometric morphometric and traditional morphometric techniques. morphometric parameters were obtained from 2d pictures of skulls using the software imagej and allometric growth pattern was calculated as a power function of total length using non-transformed data. the results revealed significant differencesbetweendifferent parts ofthe skullin both two sexes.allometric growth patternalso showedthat differencebetweenmales and femalesduring their ontogenic growth of skull.results showed that during development of skull parts from immature to adult in male and female, similargrow pattern will continuetoa certainage until sexual dimorphism appears. growth patterns is a factorfor the sexual dimorphism differences. different charts shows more consolidate in different parts of the male skull.based on the results, there is significant differences between skull shape of male and female of brown bear skull in ventral, dorsal and lateral faces. according to the results males in different parts of the skull is stronger whereas have shown more length, narrower andweaker in females.