Hamadryas Baboon (Papio hamadryas) Fact Sheet: Behavior & Ecology

Activity Pattern

• Diurnal (Kummer 1968b; Sigg and Stolbe 1981)
• Wander in daily marches to feed and find water
• Sleep on cliff faces at night (Kummer 1968b; Sigg and Stolbe 1981)

Morning congregation (Kummer 1968b)

• Awake near sunrise
• Troop begins to congregate in an open spot above cliff
• Napping, chasing, social grooming within One-Male-Unit (OMU)
  • Further description below under social groups
• Copulation during this time
• Juveniles play
• Congregation behaviors last 30 minutes to 3 hours

Daily march and foraging (Kummer 1968b)

• Troop leaves together
• Groups forage in different directions
• Bands turn off at intervals
• OMUs split from bands
• Re-group at water souces, mid-afternoon during dry season
• Travel covers 4-14 km daily (Kummer 1968b; Sigg and Stolba 1981)

Afternoon and evening activities (Kummer 1968b)

• Return to sleeping cliffs
  • OMUs return Individually
  • Generally visit the same cliff each day
• First arrivals around 15:30-16:30
• Social grooming and copulations may occur
• Troop reforms on sleeping cliff before dusk

Size

• c. 28-30 km² (as reported by Sigg and Stolbe 1981; Swedel 2002b)

Seasonality

• No clear seasonal change in daily march (Sigg and Stolbe 1981; Swedel 2002b)

Unique social group structure (summarized from Abegglen 1984; Kummer 1968a; Kummer 1968b)

• Males are the center of group cohesion and serve as group leaders
•   Unique among baboon species; hamadryas are not matrilineal
• Maintain highly ordered social groups
• Small groups interact in a fusion-fission social structure, forming large troops that congregate at night and dispand in search of food during the day

Group organizational levels (summarized from Abegglen 1984; Kummer 1968a; Kummer 1968b)

• Troop: largest grouping; all individuals sleep on rock cliff
  • 100 or more individuals
  • Composed of a few bands
• Band: individuals forming sub-groups within a troop; often composed of related individuals
  • 30 to 90 individuals
  • Composed of many One-Male Units (OMU)
  • Form a single column, moving together at start of daily march
    • Direction independent of other bands
  • Adult members rarely interact with those in other bands
    • Fights sometimes occur between bands
• OMU: solitary reproductive male and his female "harem"
  • Core core social unit; reproductive adults typically permanent members, juveniles disperse to OMU's within their band
  • 1 to 9 females and their offspring
  • Male uses aggression and threats to maintain females (Bachmann and Kummer 1980; Kummer 1968b)
    • Some female choice
  • Male mate only with females within the OMU
    • Female rarely promiscuous

Between males within a One-Male Unit (OMU) (from Kummer 1968b unless otherwise noted)

• Aggression variable across geographic range
• Males fight for control of a female
• Generally as a series of bouts (Bachmann and Kummer 1980)
  • Intermissions: female joins and clasps one male (Bachmann and Kummer 1980)
• Female preference possible (Bachmann and Kummer 1980)
  • Winner not always most physicaly dominant
• Injuries rare
  • Torn-nostril and bleeding shoulder only observed injuries from several hundred fights (Kummer 1968b)

Between OMU leader and outside males (from Kummer 1968b unless otherwise noted)

• Rare
• Short in duration (a few seconds)
• Ends in fleeing or abrupt display of absolute advantage toward victor (eg. exposing side of one's neck to opponent)
• Technique/Strategy
  • "Fencing": rapid back and forth head movement, jaws open without touching
  • Bites directed toward shoulders or neck
  • Hands direct hits toward face

Between females (from Kummer 1968b unless otherwise noted)

• Always with a male onlooker
  • To gain support from a male
  • Female may present to male while directing aggression toward another female
• Never between females of different units
• Displays:
  • Raising eyebrows
  • Screaming
  • Slapping the ground
  • Hitting

Between males and females (from Kummer 1968b unless otherwise noted)

• Toward females to maintain her presence within the OMU (Abegglen 1984; Kummer 1968b)
  • Initiated when female strays too far away
• Displays (in order of escalation):
  • Staring with raised brows
  • Loud vocalization
  • Hitting gently on hands or head
  • Neck biting
• Not all displays performed or undertaken in order
• Bites severe, though they rarely result in injury
  • Females may be lifted off the ground

Play behaviors (Kummer 1968b)

• Wrestling
• Biting
• Chasing

Grooming (from Kummer 1968b unless otherwise noted)

• At sleeping cliffs; occasionally during foraging breaks
• Female activity, most often
  • Commonly groom OMU leader and own offspring
  • Unclear how often females groom one another, conflicting observations (Kummer 1968b; Swedell 2002a)
  • OMU size may influence behavior between females (Swedell 2002a)
    • Positive correlation with unit size
    • Negative correlation with degree of females' interaction with OMU leader

Tongue and lip smacking (Kummer 1968b)

Hamadryas Baboon audio provided by the Cornell Lab of Ornithology Macaulay Library and BBC Nature

Staccato-coughing (from Kummer 1968b)

• By males to warn females
• Sign of submission by combatant

Screaming, squealing (from Kummer 1968b)

• Sign of submission or distress

Grunting (from Kummer 1968b)

• A comfort behavior

Humming (from Kummer 1968b)

• Done by infant when left by mother

Walking (Nowak 1999)

• Swaggering gait on four limbs

Running (Nowak 1999)

• "Rocking horse" gallop (as do all baboons)

Swimming (Nowak 1999)

• Reported to swim well

Hybrids

• Hybridize with neighboring baboons (Papio annubis and P. cynocephalus) (Kummer 1968b; Kummer 1995)
• Male hamadryas tend to "kidnap" females of other species

Mixed foraging parties

• Foraging parties formed with gelada baboons near lower regions of the Ghermanu River (Kummer 1968b)
• No direct interaction between the species has been reported
• Species sleep apart on cliffs at night

Canine teeth have sharpened back edges. Hamadryas baboons can inflict severe wounds during fights, but choreographed fighting prevents most serious injuries.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Grooming provides comfort and appeasement.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Abegglen (1984)
Bachmann and Kummer (1980)
Kummer (1968a)
Kummer (1968b)
Kummer (1995)
Nowak (1999)
Sigg and Stolbe (1981)
Swedell (2002a)
Swedell (2002b)