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Primates and Human Evolution

Sep 17, 2025

Overview

This lecture covers the biological anthropology subfield, focusing on primate characteristics, taxonomy, behavior, and their relevance to human evolution and conservation.

Biological Anthropology and Primates

  • Biological anthropology studies human evolution through the lens of primate biology and behavior.
  • Humans share a common ancestor with other primates but did not descend from monkeys.
  • Observing non-human primates helps us infer evolutionary processes and adaptations.

Importance of Studying Primates

  • Studying primates clarifies human evolutionary traits (e.g., language, bipedalism) and why they evolved in humans.
  • Comparison of instinctive behaviors in non-human primates and learned behaviors in humans provides evolutionary insight.
  • Primate behavior models early human social structures and cultural traits, including marriage rules and tool use.

Primate Characteristics and Behavior

  • Primates have prehensile (grasping) hands/feet (except humans with limited grasping feet).
  • Most have nails, not claws, and forward-facing eyes for stereoscopic (3D) vision.
  • All primates possess relatively large brains for their body size, facilitating complex social behavior.
  • Primates usually have single offspring with prolonged infant dependency due to learning needs.
  • Most are diurnal (active during the day), social, and omnivorous (mixed diet).
  • Modes of locomotion include brachiation, quadrupedalism, knuckle walking, climbing, and only habitual bipedalism in humans.

Primate Taxonomy

  • Primates are split into Strepsirrhini (less relevant to humans) and Haplorhini (includes humans).
  • Haplorhini divides into Platyrrhini (New World monkeys) and Catarrhini (Old World monkeys and apes).
  • Platyrrhini may have reached the Americas via rafting from Africa.
  • Catarrhini further split into Cercopithecoidea (Old World monkeys) and Hominoidea (apes and humans).
  • Humans are the only remaining species in the Homo family, but multiple human species existed historically.

Primatology Research Areas

  • Primatologists study communication (closed in non-human primates; open in humans), social structure, aggression, and affiliative behaviors.
  • Tool use in primates distinguishes between echoacts (natural, unmodified tools) and artifacts (modified tools).
  • Social dominance in primates can be male-led, female-led, or egalitarian, mostly by instinct.

Conservation and Modern Issues

  • Many primate species face threats from habitat destruction, pet trade, and being considered pests.
  • Conservation efforts focus on maintaining environments and social groupings critical for primate well-being.
  • Understanding primate social needs helps inform ethical zoo practices and rehabilitation.

Key Terms & Definitions

  • Biological Anthropology — study of human evolution and biology within anthropology.
  • Primate — order of mammals including humans, monkeys, and apes, characterized by grasping extremities and large brains.
  • Prehensile — adapted for grasping or holding.
  • Stereoscopic Vision — three-dimensional vision from forward-facing eyes.
  • Haplorhini — primate suborder including tarsiers, monkeys, apes, and humans.
  • Platyrrhini & Catarrhini — infraorders within Haplorhini: New World and Old World monkeys/apes.
  • Echoact — use of an unmodified object as a tool.
  • Artifact — a tool intentionally modified for a specific purpose.

Action Items / Next Steps

  • Review primate taxonomy charts, especially page 36 in the textbook.
  • Study distinguishing features of major primate groups.
  • Prepare for upcoming chapters on human evolution and cultural anthropology.