ANTH413 T1 (ME)

Suborder Strepsirrhini

Lemurs, Lorises, Galagos, moist nose, longer snouts for scent marking, large eyes (tapetum lucidum), predominantly nocturnal, dental comb + grooming claw on foot, highly olfaction-reliant

Suborder Haplorrhini

Tarsiers, monkeys, apes, humans, dry nose, flatter faces + shorter snouts, no tapetum lucidum, predominantly diurnal, lager complex brains + colored vision, visual dominance

Intergroup feeding competition

coordinated group living allows defense of localized high value food resources against rival groups, often shaping female bonded groups

Predation protection

Detection (more eyes and ears) and deterrence (active group defense and mobbing), dilution (the selfish herd effect, reducing an individual’s personal probability of capture)

Access to mates

group living provides proximity to potential mates, explains why males migrate to join established social groups

Social organizations

cohesion dynamics (stable groups, fission-fusion: The parent group regularly splits into smaller foraging subgroups (parties) that fluctuate in composition before recombining), uni-level, multi-level

Western lowland gorillas (Gorilla gorilla gorilla)

uni-male/multi female social organization led by a dominant male silverback, knuckle walking quadrupedelism, pronounced sexual dimorphisms (males are double in female body size), intrasexual selection

Mandrill (Mandrillus sphinx)

Large multi-male/female groups or multi-level aggregations. Female bonded kin groups from the core social structure. Quadrupedal walking/running on the ground and large branches. Extreme secondary sexual characteristics driven by sexual selection. Males posses vibrant red and blue facial and skin coloration, body size, and elongated canines. Cheek pouches to store food during competitive foraging.

Colobus monkeys

Variable social structure ranging from small uni-male/multi-female units to larger multi-male social groups with high levels of natal dispersal. Arboreal quadrupedalism, semi-brachiation, and powerful leaping. Vestigial or absent thumbs to facilitate hook-like hand placement during rapid arboreal locomotion

White handed Gibbon (Hylobates lar)

Pair bonded family units consisting of an adult male, adult female, and dependent offspring. True brachiation (hand over hand), bipedal walking on branches or ground. Elongated forelimbs relative to hindlimbs, loud morning duet vocalizations to mark and defend

Red fronted lemurs (Eulemur rufifrons)

Multimale/multifemale groups characterized by relatively balanced sex ratios and seasonal breeding synchrony. Arboreal quadrupedalism and leaping. Retain strepsirrhine characteristics (wet nose, tooth comb, reliance on olfactory)

B+W lemurs (Varecia variegata)

Fission-fusion social groups ranging from small pair-bonded units to larger flexible communities depending on resource availability. Obligate frugivore. Females build arboreal leaf nests for infant liters rather than carrying them. Grooming claws, dental comb, and tapetum lucidum.

Ring tailed lemur (Lemur catta)

Multimale/female groups organized around female dominance hierarchies, where females systematically dominate males in agonistic interactions and priority of access to food. Highly semi-terrestrial, walks quadrupedally on the ground. Black and white ringed tail for visual communication, scent glands for stink fights where secretions are rubbed onto tails and flicked at rivals.

Research design cycle

Formulate research question, generate hypothesis (null and alternative), derive predictions, identify variables (independent - age, rank, sex. dependent - time in social contact, number of unique social partners), data collection and analysis plans

Ethogram rules

Mutually exclusive definitions ( Definitions must be defined so that a single behavioral action can only fit into one specific category at any given instant.) , exhaustive (Must cover every possible state or event an animal exhibits during an observation session. To satisfy this, every ethogram must include the categories "Other" and "Out of Sight".), objective (avoid intentionality)