Giraffes (Giraffa spp.) Fact Sheet: Behavior & Ecology

Diel activity (Wilson and Mittermeier 2011; Dagg 2014; except as noted)

• Active day and night
• Day
• Most active during early and late hours of the day, especially in warmer climates.
• Active hours spent moving, feeding, and ruminating (chewing pre-digested food)
• Hottest part of the day spent resting and ruminating
• Often stand in the shade or orient their bodies towards sun to reduce sun exposure.
• Night
• Sleeping, resting, moving, feeding, and ruminating.
• More active on nights with bright moonshine (Estes 1991).

Sleep (Dagg 2014, except as noted)

• Sleep patterns of wild giraffe poorly understood (David O'Connor, personal communication)
• Short periods of sleep, day and night
• Typically no more than a couple of hours at a time.
• Usually shallow, with ears twitching and eyes half open.
• A deeper sleep may be reached but typically only lasts for 5-10 minutes at a time.
• Will lie down during part of the night, but mostly sleep standing up.

Home ranges

• Movements not well-understood
• Nonexclusive and overlapping, including among males and females (Bercovitch and Berry 2009a)
• No evidence of territories or harems (Wilson and Mittermeier 2011; Bercovitch and Berry 2014)
• Size varies by gender and with food availability, rainfall, presence of water, temperature, herd size, etc. (Dagg 2014).
• Also, wide variation among individuals
• Average home range sizes seem to vary greatly.
• Dagg (2014) reports a range of 8.6 km² in heavy vegetation to 160 km² in open grassland.
• Notably larger home ranges reported in harsher areas
• Largest reported by Fennessey (2009): 1950 km², Namib Desert
• Much more constricted and concentrated near water during the dry season (Wilson and Mittermeier 2011; Bercovitch and Deacon 2015).

The social lives of giraffes—still a puzzle

• Social, but duration of social bonds not well-understood due to few longitudinal behavior studies (Bercovitch and Berry 2009a).
• Contradictory findings: "Giraffe society has been characterized as both a loose and constantly shifting amalgamation of non-bonded individuals...as well as a structured community network..." (Bercovitch and Berry 2012)

Earlier studies (VanderWaal et al. 2014 and as noted)

• Concluded temporary, non-preferential associations based on frequent, shifting group patterns (e.g., Le Pendu et al. 2000).
• However, shorter-term affiliations may not indicate a lack of social bonds (Bercovitch and Berry 2009a).

Recent studies yield new insights

• Social structures more complex than previously thought (VanderWaal et al. 2014).
• Evidence of non-random associations from a few studies
  • More studies needed to draw generalized knowledge for the species (David O'Connor, personal communication)
• Multiple levels of social organization, as demonstrated using social network analysis (e.g., Bashaw et al. 2007; Shorrocks and Croft 2009; Carter et al. 2013; VanderWaal et al. 2014).
  • Fission-fusion dynamics embedded within a larger structure of cliques, subcommunities, and communities.
  • Do not seem to have a discernible hierarchy (may be revealed with additional studies)
• Likely, a highly fluid social structure: dynamic composition of individuals in a herd, even over short periods of time (except the mother-young bond).
  • More research needed
• Gender, shared habitat use (home range overlap), kinship, age, familiarity, and individual social preferences and avoidances mediate association preferences (Carter et al. 2013; VanderWaal et al. 2014; Bercovitch and Deacon 2015).

Gender-dependent associations

• Female-female associations more common than male-male or female-male associations (Dagg and Foster 1982; Bercovitch and Berry 2012).
• Females and males often occupy different social networks; sexes sometimes segregated (VanderWaal et al. 2014).
• Female associations not random; likely make the strongest long-term associations. Males may or may not form non-random associations (Carter et al. 2013, VanderWaal et al. 2014).
• Shared space use and kinship: influence female social organization more strongly than that of males (Bercovitch and Berry 2012; Carter et al. 2013; VanderWaal et al. 2014).
• Adult males more solitary than females; often travel as singletons (Le Pendu et al. 2000; Bercovitch and Berry 2009a).

Females

• Kin-based bonds among females: sister-sister, mother-adult daughter (Bercovitch and Berry 2012)
  • Mothers observed with adult offspring of up to 10 years old
  • Maternal kin of up to 3 generations
• Females very social when not guarding newborns. Usually found in congregations of other females and young.
• Some females stay in their natal areas (Carter et al. 2003).

Males

• Subadult males tend to be part of 'bachelor herds,' usually leaving their natal area (Dagg 2014).
• Formation of all-male herds may help males learn distributions of food and females (Bercovitch and Berry 2014).
  • Younger males likely follow and learn from older males.
  • Possibly temporary protection against predators.
• Younger males observed in groups.
  • Social cliques of younger males represent familiar individuals that are repeatedly observed together (VanderWaal 2014).
• Older males observed alone, in pairs, or with females.

Group size

• Loose herds. Group size commonly small, 3-10 individuals, but can be much larger—more than 100 individuals (Le Pendu et al. 2000; Bercovitch and Berry 2009a, 2012; VanderWaal et al. 2014; David O'Connor, personal communication).
  • Mean herd size may be larger and more variable during the wet season.
  • Habitat type (vegetation open vs. dense), competition within a group for food, and soil condition may also affect group size.
• Herd may be spread out over large areas.
  • Because of well-developed eyesight and high head height, giraffe are able to stay in communication with one another, even if physically far apart.
• No evidence for a 'group leader'; more research needed on potential for any matriarchial structuring (VanderWaal et al. 2014).

Play (Seeber et al. 2012 Table S7; Dagg 2014)

• Young calves can be very playful, jumping and running near their mothers.
• Buck, kick, and nip others
• Calves tend not to chase each other.
• May try to play with adult giraffes.

Aggression

• Subadult males play-fight with one another.
• Adult males use horns and heavily ossified skulls during combative interactions. Head slams into neck, body, and/or legs, like a club (Seeber et al. 2012 Table S5).
• Less intense encounters between males include rubbing heads and necks against another giraffe's body ("necking/rubbing"), and leaning into one another, possibly to assess strength and weight of an opponent.
• Dominant males may carry head/neck very high or parallel to ground; also a tense, arched neck (Seeber et al. 2012 Table S5).
• Submissive males may carry head low, ears downward, or assume a feeding position with head stretched upward (Seeber et al. 2012)
• Once dominance is established, combatants often coexist peacefully after a fight. Victors do not chase losers out of the area.
• Relative size, pelage color, fighting skill, and body condition may play a role in establishing male dominance. Stable dominance hierarchies among males are thought unlikely because adult males rarely associate with the same individuals (Bercovitch and Deacon 2015).

Maternal behavior (Seeber et al. 2012 Table S8)

• Neonate cleaning: drying off a newborn calf
• Suckling initiation: approaches calf and allows nursing
• Olfactory bonding: Mother touches the calf on the head, mane, back, or rump with her nose. Licks the calf's body. Frequently sniffs newborn; may strengthen the mother-calf bond.

Visual Cues

• Excellent vision with potentially long-range visual acuity (Mitchell et al. 2013; Baotic et al. 2015)
  • Large eyes: A larger retina surface area and longer focal length than all land mammals, including elephants.
  • Thought to have a high resolution, similar to other browsing artiodactyls (camels, eland, kudu).
  • Eye mass is large compared to their body mass but about that expected for their brain mass.
• Seem to have co-evolved good vision and a periscope-like ability to see above tree level in open woodland savanas (genetic comparisons with okapi studied by Ishengoma et al. 2017)
• Pay visual attention to social partners, especially those nearby (Cameron and du Toit 2005).
• Visual monitoring may be the main way giraffe gain information from one another (Bercovitch and Deacon 2015).
  • Keen adaptations for visual perception, although giraffe perceptual abilities have not been researched.

Vocal Behavior

• Can vocalize, but seldom do. May have a minimal role in communication (Dagg 2014; Bercovitch and Deacon 2015).
• May use vocalizations more when vision is limited (Baotic et al. 2015).
• Scientific investigation is needed (Baotic et al. 2015).
• A range of vocalizations anecdotally reported (few acoustic descriptions exist):
  • Snort and burst through the nostrils. Most commonly heard vocalization. Atonal. May signal alarm, annoyance, or be used when approaching each other (Baotic et al. 2015).
  • Bleat or mew by calves (captured at 1 min, 46 sec of this YouTube video)
  • "Roaring bellow" by females looking for their young (Toon and Toon 2004)
  • "Raucous cough" by males during courtship (Toon and Toon 2004)
  • Nighttime "humming" (Baotic et al. 2015)
    • Discovered while studying captive giraffes
    • Low-frequency with a rich harmonic structure
    • Only recorded at night (so far)
    • Need context information to better understand function. Possibly contact calls or to convey important information.
    • Examples of hums from Baotic et al. (2015): Audio Sample 1, Audio Sample 2, Audio Sample 3
  • Also "brrr," grunt, snort, sneeze, moan, snore, growl, hiss, and flute-like sounds (Toon and Toon 2004; Baotic et al. 2015)
• Research, in progress, may provide evidence of communication via infrasound (Matt Anderson SDZG, personal communication)
• Audio (BBC Nature)

Smell and Scent Marking

• Unlike okapi, do not have scent glands on hooves.
• Depend more on vision than smell.
• Males sniff females to determine reproductive status.
• Some giraffe may emit a strong odor; atrributed to to two alkaloids (Dagg 2014).
  • 11 volatile chemicals detected in one study.
  • May repel microorganisms or parasites; adaptive significance not well-understood.

Touch/Tactile Interactions

• Neck rubbing, "necking" (Seeber et al. 2012 Table S3; Dagg 2014)
  • One giraffe rubs its head or neck against another giraffe's body.
  • Seems to serve a social purpose rather than primarily for scratching itches.
  • Seen between young bulls; sometimes leads to sparring (a behavior of similar motions to fighting, but vigorous) and mounting.
• Nuzzling (Seeber et al. 2012 Table S3)
  • Greetings observed more frequently exchanged between cows and calves than between adults
  • Seems to strengthen social bonds

Walking (Toon and Toon 2004)

• Alternate moving the two right limbs together and then the two left.
• Advantage: keeps front legs from tangling with hind legs.
• Camels and horses walk this way.
• Video: walking gait

Galloping

• Use front legs together, then back, alternating between front and back. Hind feet stay outside of the forelegs, so there is no contact. Rabbits run this way.
• Can run up to 60 km/hr (37 mi/hr).

Jumping

• Able to jump over cattle fences.

Predator defenses (Wilson and Mittermeier 2011; Dagg 2014)

• Adults: large size, good vision, fast runners, powerful kickers.
  • Chop kick front legs, backwards kicks of hindlegs
• Calves are most vulnerable. Use camouflage as most effective defense.
• Calves grow very fast their first couple of years (double in size), making them less vulnerable to predation.

Relationships with other animals

• Often seen foraging with other species, such as zebra, antelope, and ostrich.
• May act as sentinels for other animals, due to their height and ability to see danger from far away. An alarm reaction by a giraffe quickly alerts the other animals.
• Oxpecker birds climb all over giraffes, picking off ticks and other ectoparasites. The oxpecker's shrill alarm call serves as a warning to other animals of approaching danger, but it is unlikely that giraffes need to take advantage of this benefit.
• Piapiacs and cattle egrets feed on insects that are stirred up in the wake of a walking giraffe.

Ethogram

•  For detailed behavioral descriptions, see Seeber et al. (2012)
• Groups 65 giraffe behaviors into 7 categories

Two-week old male, Congo, gallops at the San Diego Zoo Safari Park. Congo was born June 22, 2015.

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

Baotic et al. (2015)
Bercovitch and Berry (2009a)
Bercovitch and Berry (2012)
Bercovitch and Berry (2014)
Cameron and du Toit (2005)
Coe (1967)
Dagg (2014)
Estes (1991)
Fennessy et al. (2001)
Guggisberg (1969)
Innis (1958)
Le Pendu et al. (2000)
Leuthold and Leuthold (1978)
Mitchell et al. (2013)
Seeber et al. (2012)
Shorrocks and Croft (2009)
VanderWaal et al. (2014)
Wilson and Mittermeier (2011)