Kingdom: Animalia
    Phylum: Chordata
        Class: Mammalia
             Order: Artiodactyla
                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)

• Subspecies:
  • Nine subspecies have been described based on type of spotting pattern, color, and geographic origin.
  • But subspecies can and do readily interbreed, especially in captivity, resulting in hybrids with an intermediate pattern.

• Giraffe/Giraffa comes from the Arabic word "zarafah", which means "one who walks swiftly" (Gotch, 1995).
• Camelopardalis = camel (camelus), leopard (pardus); Latin. Centuries ago, it was thought that giraffes were part camel and part leopard.
• Local names: Twiga (Swahili), Nduida (Kikuyu), Oloodo-kirrangata (Masai). There are numerous other names in various local languages -Kingdon (1979) lists 20.

• Earliest giraffid: Palaeotragus from the Miocene of Asia, approximately 20 million years ago. Looked very similar to the modern okapi -medium sized, with normal length limbs and neck, and two small, bony horns.
• Giraffids were once very widespread and diverse. Fossils have been found from Greece, Austria, Hungary, the Balkans, Spain, the Middle East, Mongolia, China, Japan, Russia, India, Sri Lanka, Myanmar and Africa. Many species had large, stocky bodies and various types of heavy, ornate horns.
• Closest living relative: Okapi
• Closest relative to the Giraffidae: Cervidae (deer)

Giraffe distribution, from East 1998. Click on map for larger image.

• Historic:
• 10,000 years ago, present throughout Africa
• As northern Africa became drier, eventually turning into desert, giraffes disappeared from northern and Saharan Africa.
• 4,000 years ago disappeared from Egypt; 1,400 years ago disappeared from Morocco.
• Present: Patchy, non-continuous distribution in portions of Sub-Saharan Africa. Not present in most of western, central, and far southern Africa.

• Savannahs, especially where Acacia, Commiphora and Terminalia dominate.
• Semi-arid, open woodlands with scattered trees and bushes.
• Not in deserts, mesic forests, or mountains.

• Tallest mammal, with very long neck.
• Short, stiff mane and long tuft of hair at the end of the tail.
• Shoulders high, sloping down to hind quarters. Legs of approximately equal size. Apparent slope caused by tall dorsal spines on the thoracic vertebrae.
• No upper incisors or canines
• Horns
• Not true horns; specific to the Giraffidae
• Permanent, bony, and unbranched. Covered with skin and hair.
• Up to 13.5 cm (5.3 in).
• A single pair present in males and females; some populations have additional knobs (may look like smaller horns) on center of forehead in front of main pair, or behind the ears. See Sexual Dimorphism below for differences between male and female horns.
• See Life Stages regarding horn development
• Long (50 cm, 20 in.), prehensile tongue.
• Large, brown eyes, bordered by long, black lashes.
• Large, hooved feet.

• Background is medium to reddish brown. Broken into splotches by buff colored borders.
• 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 been observed).

• Size: Males quite a bit taller and heavier than females.
• Horns
  • Males: Horns are larger; ends have hairless knobs
  • Females and young: ends are straight and tufted with hair;
• The skull of a mature male has extensive ossification over front of skull, above eyes, and on rostrum. Typically weighs 2-3 times that of a female. Females may have additional bony knobs on forehead, like the male, but do not have such extensive bony areas.

• Neck: Like other mammals, possess only 7 cervical vertebrae. Each has been greatly elongated to produce the longest mammalian neck.
• Color vision: Can distinguish between red, orange, yellow-green, green, blue and violet.
• Circulatory System: Giraffes have specializations that regulate blood flow to the 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 up. Either scenario could result in fainting.
• Large Heart: The heart must work against gravity to pump blood up to the head when it is erect. The heart is approximately 61 cm (24 in.) long, weighs 11 kg (25 lbs), and can pump 60 - 75 liters (16-20 gallons) of blood per minute.
• Valves and large veins: The jugular vein and its offshoots contain numerous one-way valves to prevent blood from back flowing to the brain, when the head is lowered. Acting as a blood reservoir, the jugular vein is large (2.5 cm, =1 inch, in diameter), and elastic so that it can stretch, counteracting the force of gravity on the blood.
• Muscle fibers: Muscle fibers surrounding the veins leading to the heart slow the flow of blood when the head is raised again.

• 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).
• Sleep:
  • 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 open.
  • 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 populations. See Aggression and Displays.

• Non-territorial.
• Home ranges
• Average home ranges, some examples from Kenya:
  • El Karama Ranch, 14 km² (5 mi²).
  • Nairobi National Park, 73.5 km² (28 mi²).
  • Tsavo National Park, Kenya 164 km² (63 mi²).
• Varies tremendously among individuals and between wet and dry season, from 5 to 654 km² (2 - 252.5 mi²).
• During the dry season home range is much more constricted, and concentrated near water than during rainy season.
• High level of overlap between individuals (both males and females).

• 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 the area.

• 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 hearing. 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:
  • Alarm snort
  • 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.

• 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 way.
• 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:
  • Adults: large size, good vision, fast runners, powerful kickers.
  • Calves are most vulnerable, and use camouflage as most effective defense.
  • 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.

• Assessment of reproductive receptivity: Solitary male checks females in a heard 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 to mate.
• 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.

• 425-465 days

• 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.

• 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.

• Horn development
  • Horns fully developed at age 4 - 4.5 in males and age 7 in females.
  • 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.
• Maturity: 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)
• Captivity:  The age range of  the 8 oldest giraffes held in captivity -all deceased and all females- is 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.

• Internal parasites:
  • Flukes
  • Tapeworms
  • Whipworms
  • Warble fly larvae, Rhinoestrus giraffae - parasitic maggot that burrows into lining of nose and throat.
• External parasites:
• ~15 species of ticks
• tsetse flies -carriers of trypanosomes (giraffes are immune to trypanosomaisis)
• Other
• Rinderpest, infectious viral disease;  giraffes less susceptible than other ruminants, but some individuals can become temporarily blind or die during an epidemic.
• Anthrax, a bacterial infection.

• History of captivity
  • 14th century BC: art in King Tutankhamen's tomb shows haltered giraffes.
  • 525 AD: written account of giraffe as one of Ethiopian King's pets.
  • 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 early 1800's
  • Zoos in Europe, North America, Japan, and Australia/New Zealand have the majority of captives.
• San Diego Zoological Society
  • 1938: First pair of giraffes come to the Zoo -Lofty and Patches.
  • Subspecies at the Zoo and Wild Animal Park: Masai (G. c. tippelskirchi), Reticulated (G.c.reticulata), and Rothschild's/Uganda (G.c. rothschildi).
  • Fresh acacia branches are collected daily from the zoo's forage farms. In addition, giraffes are fed alfalfa, carrots, apples, and onions.
  • CRES research: Reproductive endocrinology - Fecal samples are collected daily and then tested for level of progesterone (a hormone related to reproduction in females). These results are compared to behavioral observations in order to better understand how the two are related.