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In-Depth Notes on Primates and Old World Monkeys

Taxonomy of Primates

  • Superfamily: Cercopithecoidea

    • Order: Primates
    • Suborder: Haplorhini
    • Infraorder: Tarsiiformes (all tarsiors)
    • Parvorder: Platyrrhini (all New World monkeys)

  • Family Classification:

    • Cercopithecoidea (Old World monkeys)
    • Subfamily: Cercopithecinae (e.g., baboons, macaques)
    • Subfamily: Colobinae (e.g., colobus monkeys, langurs)
    • Hominoidea (apes and humans)
    • Family: Hominidae (great apes and humans)
      • Subfamily: Ponginae (orangutans)
      • Subfamily: Gorillinae (gorillas)
      • Subfamily: Homininae (chimps, bonobos, humans)
    • Family: Hylobatidae (gibbons and siamangs)
    • Platyrrhini (New World monkeys)
    • Family: Cebidae (e.g., capuchins, squirrel monkeys)
    • Family: Atelidae (e.g., howler monkeys, spider monkeys)

Characteristics of Old World Monkeys (OW Monkeys)

  • Physical Traits:

    • Arms and legs are approximately equal in length
    • Narrow thorax
    • Less mobile wrists compared to apes
    • Larger number of lumbar vertebrae
    • Non-prehensile tails
    • Dental formula: 2,1,2,3/2,1,2,3
    • Bilophodont cusp pattern on lower molars

  • Comparative Anatomy (OW Monkeys vs. Apes):

    • Apes have arms longer than legs, broad thorax, and no tail.
    • Apes exhibit a Y-5 cusp pattern on lower molars instead of bilophodont.

Locomotion and Behavior

  • OW monkeys are quadrupedal, traversing both ground and arboreal environments.
  • Mating system typically polygynous:
    • Sexual dimorphism observed: males larger than females.
    • Infanticide:
    • After a male ousts a dominant male, he may kill infants to induce the mothers to ovulate again.

Diet and Feeding Habits

  • Cercopithecinae (e.g., baboons):

    • Diet: Omnivorous (fruits, seeds, insects).
    • Anatomical specialization: cheek pouches for food storage.

  • Colobinae:

    • Diet: Folivory (mainly leaves).
    • Anatomical specialization: Complex stomachs for digesting large amounts of leaves.

Mating Systems

  • Subfamily Cercopithecinae:

    • Example: Savanna baboon (Papio anubis) exhibits multiple-male polygyny with males emigrating from birth troops, maintaining separate hierarchies.
    • Example: Gelada baboon (Theropithecus gelada) exhibits one-male polygyny.

  • Subfamily Colobinae:

    • Exhibits one-male polygyny as well, with quadrupedal locomotion and an arboreal lifestyle.

Cultural Behavior in Non-Human Primates

  • Cultural Examples:
    • Japanese macaque washing sweet potatoes demonstrates learned behavior, suggesting cultural practices exist among non-human primate species.