The animals show very little sexual dimorphism; the males are only slightly larger than the females.
Most Catarrhine species show considerable sexual dimorphism and do not form a pair bond.
Members of this family frequently show clear sexual dimorphism.
They show sexual dimorphism, with females being longer-billed and heavier than males.
They show marked sexual dimorphism, with only the males having horns.
Male and female birds show very strong sexual dimorphism.
They are brightly coloured fish, often showing striking sexual dimorphism.
Some races show sexual dimorphism during the breeding season.
It shows striking sexual dimorphism compared to most of its relatives.
Some species do not show sexual dimorphism; both male and female can have or lack ornamentation.