Question

Northern white-cheeked gibbon is a small tree-dwelling ape in which males and females are equally choosy when it comes to mate choice. What would you predict about: 1) their mating system, 2) allocation of parental care, 3) operational sex ratio, and 4) differences between males and females in their productive potential?

Answer 1

White cheeked gibbon (Nomascus leucogenys) is a species of gibbon that lives in the tropical forest.They exhibit sexual dimorphism.Males are having black hair on their entire body with white patches on cheek and tuft of hair on the head.Females are reddish tanned with a black to brown fur extending from crown to nape of neck..They are primarily herbivores and arboreal in habit.They move from one tree to other by swinging through trees or brachiation.They communicate mainly through singing.They life a social life.Thier lifespan is about 28 years.They reach sexual maturity within seven to eight years and are usually monogamous.

1.Mating system : They have monogamous system of mating.Monogamy means a male and female exclusively mate each other and their bond lasts for ever.Males and females attaract each other through singing.They breed throughout the year and has a gestation period of seven months.The infants are weaned after 2 years.

2.Parental care: Unlike other mammals ,where females are the main care taker,in these gibbons the parental care is shared between male and female.Both the parents teach the infant to differentiate food sources ,learn social interactions like playing etc.Male protects female during pre fertilization,pre birth periods.

3.Operational sex ratio: It is the ratio of sexually active male to the fertilizable females at any given time.There are totally 455 gibbons in the world.

4.The menstrual cycle of females is 28 days.Females give birth to single offspring in every two to three years.At sexual maturity male Adults remain black with white cheek patches.