Q35 - Primate Mating Systems
In many species of nonhuman primates, morphology, social behaviour and mating system are tightly interlinked, making it possible to predict some traits once certain others are known.
Some traits of three primate species, A, B and C, are given in the table below.
| Trait | Species A | Species B | Species C |
|---|---|---|---|
| Average male body mass (kg) | 160.00 | 55.00 | 0.255 |
| Male to female body mass ratio | 2.00 | 1.25 | 1.10 |
| Testes mass to body mass ratio | 0.2 × 10⁻³ | 5 × 10⁻³ | 1 × 10⁻³ |
| Usual number of offspring per birth | 1 | 1 | 2 |
Q35.1. Which of the species is expected to have the highest levels of within-group male aggression?
Q35.2. Which of the species is expected to have the highest variance in number of matings per male?
Q35.3. Which of the species is most likely to live in multi-male multi-female groups, in which receptive females could mate with multiple males?
Q35.4. In which of the species are males most likely to be involved in parental care?
Question reproduced from IBO 2023, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF