Kingdom: Animalia Phylum: Chordata Class: Mammalia Order:
Artiodactyla* (Even-toed hoofed animals: includes pigs, sheep goats, cattle, deer) Suborder: Ruminantia Family: Giraffidae Genus:Okapi (Okapi) Genus:Giraffa Species:Giraffa camelopardalis Subspecies:G. c. angolensis (Angolan Giraffe) G. c. antiquiorum (Kordofan Giraffe) G. c. camelopardalis (Nubian Giraffe) G. c. giraffa (Southern/South African Giraffe) G. c. peralta (Nigerian/West African Giraffe) G. c. reticulata (Reticulated Giraffe) G. c. rothschildi (Baringo/Rothschild's/Uganda Giraffe) G. c. thornicrofti (Thornicroft's Giraffe) G. c. tippelskirchi (Masai Giraffe)
*NB: New anatomical and DNA evidence on the relationship between Artiodactyla (even-toed ungulates) and Cetacea (whales and dolphins) recently led to a merging of the two orders into a new group, Cetartiodactyla (Montgelard, 1997; reviewed in Kulemzina, 2009). As of October 2012, experts had not agreed on whether to define Cetartiodactyla as an official taxonomic order that would replace Artiodactyla and Cetacea. Some continue to list giraffes in the order Artiodactyla (Franklin, 2011) or use the term Cetartiodactyla without defining it as an order (IUCN 2008).
Giraffe taxonomy based on pelage pattern and morphology is unclear, with schemes ranging from two separate species to a single species with nine, eight, six, or five subspecies (reviewed in Brown et al. 2007).
The nine subspecies listed above were proposed by Dagg and Foster (1976), based on spot pattern, color, and geographic origin.
Mitochondrial DNA analysis of six of the subspecies indicates that all are essentially reproductively isolated; some of these may therefore represent distinct species (Brown et al. 2007).
DNA analysis indicates that G. c. peralta contains only the Niger giraffes, while G. C. antiquorum includes all populations living in Cameroon, Chad, the Central African Republic, and southwestern Sudan (Hassanin et al. 2007).
Hybridization between subspecies in the wild appears to be very rare (Kingdon 1979).
From "zarafah" (Arabic),
meaning "one who walks swiftly" (Gotch 1995)
From camelus (camel) and pardus (leopard; Latin)
Centuries ago, it was thought that giraffes were part camel and
Background is medium to reddish brown. Broken into splotches by buff
The color tends to darken with age, especially in males, but the
pattern does not change.
Each subspecies has a characteristic
type of color and pattern.
Individuals can be recognized by their unique markings.
Rarely, individuals without spots are born -all dark (almost black),
tan (spots barely visible), or white (although no true albinos have
Baringo giraffe hide
Reticulated giraffe hide
Males are quite a bit taller and heavier than females.
Males: Horns are larger; ends have hairless knobs
Females and young: ends are straight and tufted with hair;
The skull of a mature male typically weighs 2-3 times that
of a female and has extensive ossification over front
of skull, above the eyes, and on the rostrum.
Females may have additional bony knobs on forehead, but not these are not as extensive as in males.
Other Physical and Physiological Characteristics
Giraffes possess only 7 cervical vertebrae, the same as in other mammals.
In the giraffe, each vertebra is greatly elongated to produce the longest mammalian neck.
Can distinguish between red, orange, yellow-green,
green, blue and violet.
blood flow to the giraffe's head
Giraffes are up to 18 feet tall, and one would
expect blood to rush to the brain when a giraffe lowers its head to
drink, or to drain away from the brain when the head is lifted back
Either scenario could result in fainting.
High blood pressure helps maintain sufficient blood flow to the brain
Systemic (arterial) blood pressure at birth is comparable to other mammals, but it rises as a giraffe grows and its neck elongates. (Mitchell & Skinner 2009).
Average systemic blood pressure is 203 mm Hg, dropping to 100 mm Hg at the head (Mitchell & Skinner 2009; calculated average of 29 reports) .
Systemic blood pressure at the heart with the neck held 55° to the vertical is calculated to be 208 mm Hg -- nearly twice the predicted value for other species of similar mass. (Mitchell & Skinner 2009).
Heart structure: quite different from other mammals
An early study (Goetz 1955) reported a very large (11.25 kg) heart for giraffes, but this may have been an error in measurement.
A comprehensive study of the giraffe cardiovascular system (Mitchell & Skinner 2009) showed heart size relative to body mass to be comparable to that of other mammals.
Heart structure is quite different from that of other mammals
(Mitchell & Skinner 2009)
As a giraffe grows, the left ventricular and interventricular walls become much thicker than in other mammals, enabling the heart to contract much more strongly.
A giraffe heart can generate an output of 6,000 mm Hg per second, 2.5 times that of a cow heart and 5 times that of a human heart (Patterson et al. 1965).
Valves and large veins play a role when the head is lowered
Numerous one-way valves in the jugular vein and its offshoots
prevent blood from
flowing back to the brain.
The jugular vein, which is large (2.5 cm, 1 inch, in
diameter) and elastic, stretches to increase its capacity and act as a blood reservoir, counteracting the
force of gravity on the blood.
Muscle fibers play a role when the head is raised
Muscle fibers surround veins that lead
to the heart.
These contract when the head is raised, slowing the flow of blood.
BEHAVIOR & ECOLOGY
(Apfelbach, 1990; Coe, 1967; Estes, 1991; Leggett et al., 2001; Guggisberg 1969; Innis, 1958; Le Pendu et al., 2000; Leuthold & Leuthold, 1978)
Active during the day and night.
Daytime: Most active during the early and late hours of the day.
The hottest part of the day is often spent resting and ruminating. In
Transvaal, September - December, 55-83 % of the day (6 AM - 6 PM) was
spent browsing (Innis, 1958).
Night: During the night most time is spent ruminating (40-49%)
and feeding (22-34%). The rest of the time is spent resting/sleeping.
More active on nights with bright moonshine (Estes, 1991).
Bouts of sleep during the day and night usually last no more
than a couple of hours at a time.
Sleep is usually shallow, with ears twitching and eyes half
During the shallow sleep, 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 most of the time
sleep standing up.
Social, unlike okapi which are fairly solitary, but do not tend to form
long lasting bonds.
Loose herds of up to about 50 individuals. Group size usually much
smaller. No leader, and little coordination among individuals. May be
spread out over large distances. Composition of individuals changes
constantly, even within a 24 hour period.
Because of well developed eyesight and high vantage point, able to stay
in communication with one another even if physically very far apart.
Females are very social when not guarding a newborn and are usually
found in congregations of other females and young. Young females often
stay in their natal areas.
Sub adult males tend to be part of a bachelor herd, and usually leave
their natal area. Adult males become more solitary.
Although there is sometimes a segregation between sexes, herds can be
composed of any combination of males, females, young, and adults.
Dominance hierarchy among males in local
Varies tremendously among individuals and between wet and dry
season, from 5 to 654 km2 (2 - 252.5 mi2).
Much more constricted and concentrated near water during the dry season.
High level of overlap between individuals (both males and
Males use horns and heavily ossified skulls during aggressive
encounters with one another. Head slams into neck and body of another
individual, like a club.
Less intense encounters between males include mutual neck and head
rubbing (="necking"), and leaning into one another, possibly
to assess strength and weight of opponent.
Once dominance has been established, the two combatants often coexists
peacefully after a fight. The victor does not chase the loser out of
Young calves can be very playful, jumping and running near the mother.
Calves do not tend to chase each other.
Older, immature males play-fight with one another.
Dominance: Erect with straight neck and head held high, stretch neck out at angle with chin up, stiff legged approach. Often, dominance challenge is won by the individual who stands the tallest.
Submissive: Head and ears held downward, retreat.
Much more important than in Okapi, which rely more on scent and
This is exemplified by a giraffe's large eyes and preference
for open savannahs, as opposed to closed forests.
Although they do possess vocal chords, giraffes vocalize much less than okapi.
Types of vocalizations that have been reported:
Bleating or mewing by calves
"Roaring bellow" by females looking for their young
"Raucous cough" by males during courtship
Also moaning, snoring, hissing, and flutelike sounds.
Unlike okapi, do not have scent glands on hooves.
Depend on vision more than sense of smell for awareness of environment.
Males sniff females to determine reproductive status.
Mature males emit strong body odor.
Walking: Unlike most other animals, use the two right limbs
together, then the two left, alternating right and left. Otherwise,
the long front legs would tangle with the hind legs. Camels walk this
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
Jumping: Able to jump over cattle fences.
Adults: large size, good vision, fast runners, powerful
Calves are most vulnerable, and use camouflage as most
Calves grow very fast their first couple of years
(double in size), making them less vulnerable to predation.
Often seen foraging with other species, such as zebras, antelope, and
ostriches. Giraffes may act as sentinels for the other animals due to
their height and ability to see danger from far away. An alarm
reaction by a giraffe quickly spreads to the other species.
Oxpecker birds climb all over giraffes, picking off ticks and other
ectoparasites. Their shrill alarm call serves as a warning to other
animals nearby when danger approaches, but it is likely that giraffes
do not need to take advantage of this benefit.
Piapiacs and cattle egrets take advantage of insects that are stirred
up in the wake of a walking giraffe.
Browsers: leaves and young shoots. Also eat seeds and pods.
Up to 100 species of plants recorded for the giraffe's diet.
Bulk of diet usually made up of only a few species of trees and woody bushes.
Acacia spp. are favored in all locations.
Additional species differ depending on location, and include the following genera: Combretum, Commiphora, Terminalia, Harrisonia, Pterocarpus, Cassia, Lonchocarpus, and Grewia.
Rainy season: eat mostly deciduous species.
Dry season: eat mostly evergreen species.
Consume 34 - 75 kg (75 - 165 lbs) of browse per day.
Able to feed at a height unreachable by all other browsers except
for the elephant. This often creates a pruned browse line along
the undersides of trees at a height of about 4.3 - 5.5 m (14-18
Long, prehensile, sticky tongue enables a giraffe to feed on hard
to reach leaves. Small, thickened papillae of the tongue and lips
protect against thorns.
Elongated occipital condyles (where the skull attaches to the
neck) enable a giraffe to extend its head to a completely
vertical angle, increasing its reach while browsing.
Because males are so much taller than females, they will browse in
a higher region of a tree, thereby reducing competition for food.
Very little chewing when leaves first eaten. As seen in other
ruminants, leaves are quickly swallowed, partially digested, and
then regurgitated so that they may be chewed more thoroughly at a
later time (= "chewing cud"). Can chew cud at any time
of the day.
Four chambered stomach highly efficient, with numerous, long
papillae on the surface, which greatly increases the surface area
for nutrient absorption, (largest surface area of any ruminant).
During the wet season, obtain most or all water from the
leaves (and dew) that are consumed.
During the dry season, drink at least every three days, up to
38 liters (10 gallons) at a time.
Must kneel on forelegs or spread them wide to reach water
while drinking. The same is true for Okapi, suggesting that
this trait evolved before the giraffe's neck elongated.
Assessment of reproductive receptivity: Solitary male checks females in a herd by testing odor of urine ("Flehmen" — includes lip curl, helps bring odor to vomeronasal organ).
The dominant male will often guard the estrus female against other
males, and he is usually the only male in a given area that will get
He signals his readiness to mate by tapping on the female's hind leg
with his foreleg or resting his chin on her back. He usually follows
her, sometimes for hours, until she allows him to mount her.
No long term bonds are formed between male and female.
Estrus cycle: 15 days.
Breeding occurs throughout the year.
Births occur during any time of year. Some studies have shown peaks in
the dry months, others show peaks at other times of year (Foster &
Dagg, 1972; Estes, 1991).
Interbirth interval: 20-22 months (Leuthold and Leuthold, 1978).
Females tend to return to the same calving area for successive births.
A female gives birth alone. She remains alone with the calf for a week
or more, protecting it against predators, and avoiding other giraffes.
Litter Size: 1, rarely two.
Birth Weight: 47-100 kg (104 - 220 lbs)
Height: 1.7 - 2 m (5.6 - 6.6 ft)
Female gives birth standing up, and newborns drop to the ground.
Horns present at birth; formed of small bumps of cartilage, unattached to skull, covered with skin and tufts of hair.
Newborns are able to stand in about 5 - 20 minutes, and start suckling within an hour.
Infant (< 1 year old)
Predator defense: When too young to defend themselves,
calves remain still, lying on the ground, hiding near a bush or fallen
tree. Mother is often at least 10 - 25 meters (33 - 82 ft) away, and
will often leave the calf alone for several hours at a time as she
travels to water.
Crèches: After 1-4 weeks, calves may begin group together in
crèches, with mothers standing watch for predators and other dangers.
At this time, many of the mothers will leave for long periods to
browse, and will return to feed their young before dark, and stay
through the night. Sometimes a few females stay behind to care for the
young, but they can be left completely alone for several hours.
By 3 - 4 months of age, calves begin browsing and ruminating,
although there have been reports of calves tasting leaves when only 3
weeks old .
At about 4 - 6 months, calves begin to feed with the female heard.
Weaning age varies quite a bit (6 - 17 months), but most
commonly begins at 9-12 months.
Independent of mother at 12 - 18 months of age, but some
association may last a few months longer.
Males tend to wander farther, at a younger age, than females.
No difference in behavior or development between subspecies has been reported.
Horns fully developed at age 4 - 4.5 in males and age 7 in
Cartilaginous bumps grow and begin to ossify (become bony)
starting at the tip, eventually merging with skull.
Forehead area becomes more heavily ossified, forming an
additional knob in front of main horns. Present in both
males and females, but the knob on the male may develop into
what looks like a third horn.
Males: Bony growth continues all over front of skull,
including forehead, over the eyes, and on the nose. Much
more dense than that of females.
Females 4 - 5 years
Males 7 - 8 years.
In the wild:
Approximate maximum of 26 years, but 15-20 is
more common (Foster & Dagg, 1972; MacClintock, 1973)
Age range of 8 oldest recorded giraffes
in captivity (all deceased, all female): 32-40.5 years.
Females live 25% longer than males (Lackey & LaRue, 1997).
Predation of calves by lions, hyenas, leopards, and wild dogs.
Predation of adults is rare.
Hunting by humans.
(Lackey & LaRue 1997; Bercovitch et al., 2003; Ritter 1998)
History of captivity
14th century BC: art in King Tutankhamen's tomb shows
525 AD: written account of giraffe as one of Ethiopian King's
1414 AD: one giraffe was given as a gift to emperor of China,
and had to walk 3,000 miles to get there.
First arrived in Europe as gifts to various leaders in the
Currently, majority of individuals outside of the wild are at zoos in Europe, North America, Japan, Australia, and New
San Diego Zoological Society
1938: first pair of giraffes the Zoo ("Lofty" and "Patches") arrived at the Zoo.
Currently, three subspecies are housed at the San Diego Zoo and San Diego Zoo Safari Park: Masai (G. c.
tippelskirchi), Reticulated (G.c.reticulata), and
Rothschild's/Uganda (G.c. rothschildi).
Diet: fresh acacia branches collected daily from the zoo's
forage farms, as well as alfalfa,
carrots, apples, and onions.
San Diego Zoo Global Institute for Conservation Research: conservation scientists
study the relationship between female reproductive hormones (measured from fecal samples) and behavior.
IUCN Status, G. camelopardalis: Least Concern ver 3.1 (Fennessey & Brown 2010)
CITES Status, G. camelopardalis: Not listed
Giraffes are protected in most African countries where they occur.
Distribution in the wild is still
relatively widespread but reduced compared to historical records.
The species is fragmented across its range, with many populations in decline.
Although all populations are currently considered as a single species for management, Brown et al. (2007) report that genetic subdivisions exist and suggest that not recognizing this could lead to endangerment or even extinction.
IUCN Status, G. c. peralta: Endangered D ver 3.1 (Fennessey & Brown 2008)
IUCN Status, G. c. rothschildi: Endangered C2a(i) ver 3.1 (Fennessey & Brenneman 2010)
Most at risk as of 1998: G. c. peralta, G. c. antiquorum,
G.c. camelopardalis, G. c. rothschildi, and G. c. thornicroft (East 1999)
Threats to survival
Poaching: hunted by humans for pelts, horns, and meat.
Competition for land and resources by rapidly growing human population.
Habitat fragmentation, resulting in small isolated populations.