{"id":72021,"date":"2024-06-20T23:10:01","date_gmt":"2024-06-21T04:10:01","guid":{"rendered":"https:\/\/lafeber.com\/vet\/?p=72021"},"modified":"2024-08-29T01:14:02","modified_gmt":"2024-08-29T06:14:02","slug":"giraffe-fast-facts","status":"publish","type":"post","link":"https:\/\/lafeber.com\/vet\/giraffe-fast-facts\/","title":{"rendered":"Giraffe Fast Facts"},"content":{"rendered":"

Introduction<\/h2>\n

Celebrate World Giraffe Day LafeberVet-style with fast facts on this special species (Fig 1). Topics covered will include taxonomy, the range and conservation status of giraffes (Giraffa<\/em> camelopardalis<\/em>) in the wild as well as basic husbandry and common diseases of captive animals. The anatomy and physiology of the giraffe is too unique to adequately cover in this brief review, however, some interesting facts will be shared with an emphasis on the cardiovascular system.\u00a0<\/em><\/p>\n

\"World<\/a>

Figure 1<\/b>. World Giraffe Day was initiated by the Giraffe Conservation Foundation in 2014 to celebrate the world’s tallest animal on the longest day of the year. Photo: Donnie Ray Jones via Flickr Creative Commons. Clikc image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Range<\/strong><\/h3>\n

The giraffe is native to the savannas and open woodlands of Africa (Fig 2). Once widespread across the continent, giraffes are now primarily found as fragmented groups within national parks or game farms in eastern and southern Africa and as scattered populations in west Africa.5<\/a>,15<\/a>,21<\/a><\/sup> There are less than 70,000 animals in the wild.21 <\/sup><\/a><\/p>\n

\"Giraffes<\/a>

Figure 2<\/b>. Reticulated giraffes (Giraffa camelopardalis reticulata<\/em>) in Maasai Mara National Reserve, Kenya. Photo: Paul Mannix via Flickr Creative Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Taxonomy<\/strong><\/h3>\n

The International Union for the Conservation of Nature (IUCN) recognizes one giraffe species with nine subspecies (Box 1)21<\/sup><\/a>, however, genetic analyses have identified four distinct species:\u00a0 G. camelopardalis, G. giraffa, G. reticulata, <\/em>and G. tippelskirchi <\/em>(Fig 3).<\/em>6<\/a>,7<\/a>,11<\/a>,13<\/a><\/sup><\/p>\n

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\n\n\n\n\t\n\n\t
Box 1. Giraffa<\/em> sp. taxonomy<\/strong><\/th>\n<\/tr>\n<\/thead>\n

Class<\/strong>: Mammalia<\/em><\/p>
\n

Order<\/strong>: Artiodactyla<\/em>: even-toed ungulates or hoofstock<\/p>
\n

Suborder<\/strong>: Ruminantia<\/em>: four-chambered stomach<\/p>
\n

Family<\/strong>: Giraffidae: giraffe and okapi<\/p><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/small><\/p>\n

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\"Thornicroft\u2019s<\/a>

Figure 3<\/b>. Thornicroft\u2019s giraffe (Giraffa camelopardalis thornicrofti<\/em>) is a geographically isolated subspecies or species found only in northeast Zambia.12<\/sup><\/a> Photo: Manuel Schwarz via Wikimedia Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Conservation status<\/strong><\/h3>\n

The IUCN classifies giraffe populations as \u201cvulnerable\u201d, although West African giraffes (Giraffa c. peralta)<\/em> and Rothschild\u2019s giraffes (<\/em>G. c. rothschildi<\/em>) <\/em>are categorized as \u201cendangered\u201d (Fig 4).21 <\/sup><\/a><\/p>\n

\"The<\/a>

Figure 4<\/b>. The West African giraffe (Giraffa camelopardalis peralta<\/em>) was historically spread across much of the Sudano-Sahel region but is now restricted to Niger.15<\/sup><\/a> Photo: Roland H. via Wikimedia Commons. Click image to enlarge<\/em>. <\/small><\/p><\/div>\n

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Height<\/h2>\n

The giraffe is the world\u2019s tallest animal.21<\/a>,22<\/a><\/sup> Its long neck and limbs are believed to have evolved to allow better access to high foliage and to improve predator detection (Fig 5).3<\/a>,22<\/a><\/sup> The male giraffe or bull stands 5.7 m from the ground to the horns, reaching 3.3 m at the shoulders.18<\/sup><\/a> The long neck measures approximately 2.4 m.18<\/sup><\/a> Females (cows) are typically 0.7 to 1 m shorter.18<\/sup><\/a> Calves measure approximately 2 meters from the ground to the shoulders.18<\/sup><\/a><\/p>\n

\"All<\/a>

Figure 5<\/b>. Like all members of class Mammalia, the giraffe (Giraffa<\/em> spp.) possesses seven elongated cervical vertebrae. Photo: Sklmsta via Wikimedia Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Ossicones<\/strong><\/h2>\n

Giraffe horns are called ossicones.18<\/sup><\/a> These permanent, unbranched, bony protuberances are covered with skin and fur and are present in both males and females. Female horns are thin and tufted, while male horns are relatively thick (Fig 6, Fig 7).18<\/sup><\/a> Giraffe are born with small, bony cores surrounded by cartilage that is unattached to the skull and therefore able to lie flat.16<\/sup><\/a> Soon after birth, these cores begin to grow and ossify.16<\/sup><\/a> By the time the giraffe reaches sexual maturity between 3-5 years, the ossicones are completely attached to the skull (Box 2).16 <\/sup><\/a><\/p>\n

\"Female<\/a>

Figure 6<\/b>. The ossicones of female giraffes (Giraffa<\/em> spp.) are often relatively thin and tufted with fur. Photo: Rennett Stowe via Flickr Creative Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

\"Adult<\/a>

Figure 7<\/b>. Male giraffes (Giraffa<\/em> spp.) generally possess thicker ossicones. In free-ranging bulls, the top of the horn becomes bald as a result of frequent necking or sparring.16<\/a>,18<\/a><\/sup> In some species, bulls grow a second pair of ossicones on the back of the skull.16<\/sup><\/a> Giraffes also possess a central osseous protuberance, which is more prominent in males.5<\/a>,16<\/a><\/sup> Photo: Stefan Kraus via Wikimedia Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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\n\n\n\n\t\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t
Box 2. Basic biological characteristics of Giraffa<\/em> spp.5,13,18<\/sup><\/strong><\/th>\n<\/tr>\n<\/thead>\n
Parameter<\/strong><\/td>Measurement<\/strong><\/td>\n<\/tr>\n
Lifespan (wild)<\/td>10-15 years<\/td>\n<\/tr>\n
Lifespan (captivity)<\/td>20-27 years (mean: 25 years)<\/td>\n<\/tr>\n
Adult male BW<\/td>850-1930 kg<\/td>\n<\/tr>\n
Adult female BW<\/td>700-1200 kg<\/td>\n<\/tr>\n
Newborn BW<\/td>50-55 kg<\/td>\n<\/tr>\n
Dental formula<\/a><\/td>I0\/3 C0\/1 PM3\/3 M3\/3 = 33<\/td>\n<\/tr>\n
Puberty, age<\/td>3-4 years (female)
4-5 years (male)<\/td>\n<\/tr>\n
Estrus cycle<\/td>14-15 days<\/td>\n<\/tr>\n
Gestation <\/td>420-468 days<\/td>\n<\/tr>\n
BW: body weight<\/small><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/p>\n

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Physiological challenges <\/strong><\/h2>\n

The giraffe\u2019s height imposes a variety of challenges on multiple body systems, including the cardiovascular system.1<\/a>,2<\/a>,3<\/a><\/sup> Since the heart-to-head distance in the adult giraffe exceeds 2 m, the heart must generate a blood pressure twice that of other mammals to adequately perfuse the brain.5<\/a>,19<\/a>,22<\/a>,27<\/a><\/sup> The normal systolic blood pressure in a healthy adult ranges between 200 and 300 mm Hg (mean:\u00a0 200 mm Hg) at the level of the heart.1<\/a>,2<\/a>,5<\/a>,22<\/a>,24<\/a><\/sup> This high arterial blood pressure is needed to maintains cerebral perfusion pressure at approximately 100 mm Hg at the entrance to the brain.2<\/sup><\/a><\/p>\n

Blood pressure may exceed 450 mm Hg in the lower limbs. Rigid, thick-walled vessels are needed in this region to withstand elevated hydrostatic pressure.2<\/a>,3<\/a>,5<\/a><\/sup> Edema is prevented by \u201cgravity-suit-like fascia and skin<\/em>\u201d, extensive lymphatics, as well as valve-like structures in the arteries at the stifle and elbow.1<\/a>,2<\/a>,5<\/a><\/sup><\/p>\n

Although the normal giraffe does not develop edematous limbs secondary to hypertension, high blood pressure does leads to hypertrophy of the giraffe\u2019s left ventricular wall (Fig 8a, Fig 8b).2<\/sup><\/a> In most mammals, hypertension-induced left ventricular thickening leads to cardiac pathologies, such as fibrosis and heart failure, however, the giraffe heart is apparently resistant to developing cellular pathology.2<\/a>,22<\/a><\/sup><\/p>\n

\"Pressure-induced<\/a>

Figure 8a<\/b>. Pressure-induced concentric thickening of the left ventricle (as shown on the right, bottom arrow<\/em>) is associated with excellent exercise tolerance and preserved left ventricular diastolic function in the giraffe (Giraffa<\/em> spp.). Taken from the free full text: Natterson-Horowitz B, Baccouche BM, Mary J, Shivkumar T, et al<\/em>. Did giraffe cardiovascular evolution solve the problem of heart failure with preserved ejection fraction? Evol Med Public Health. 2021;9(1):248-255. doi: 10.1093\/emph\/eoab016<\/a>. PMID: 34447575<\/a>; PMCID: PMC8385250.<\/small><\/p><\/div>\n

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\"Concentric<\/a>

Figure 8b<\/b>. Concentric hypertrophy of the left ventricle in a normal adult giraffe (Giraffa<\/em> spp.). Photo: Dr. Mads Bertelsen. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Scientists still have an incomplete understanding of how cerebral circulation is maintained and protected when a giraffe lowers or raises its head (Fig 9).1<\/a>,2<\/a>,27<\/a><\/sup> We do know that large, compliant jugular veins allow blood to pool when the head is lowered.2<\/a>,5<\/a><\/sup> Baroreceptor-based regulation of vascular tone, non-collapsible vertebral veins, and valves within the jugular veins also likely play a role.2<\/a>,5<\/a><\/sup><\/p>\n

\"The<\/a>

Figure 9<\/b>. The vascular system of the giraffe (Giraffa<\/em> spp.) is uniquely designed to mitigate the potentially calamitous changes in blood pressure that could occur when a giraffe lowers its head to drink water and then swiftly lifts its head 5-6 m in one sweeping movement.1<\/a>,2<\/a>,3<\/a>,26<\/a><\/sup> Note the blood pressures in the heads of giraffes in different positions. Taken from the free full text: Natterson-Horowitz B, Baccouche BM, Mary J, Shivkumar T, et al<\/em>. Did giraffe cardiovascular evolution solve the problem of heart failure with preserved ejection fraction? Evol Med Public Health. 2021;9(1):248-255. doi: 10.1093\/emph\/eoab016<\/a>. PMID: 34447575<\/a>; PMCID: PMC8385250.<\/small><\/p><\/div>\n

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Interestingly, despite the work that must be done to pump blood vertically, the energy expenditure of the giraffe heart is similar to other mammals (relative to body weight).2<\/sup><\/a> The giraffe heart also makes up the same proportion of body mass (around 0.5%) as seen in other mammals.2<\/sup><\/a><\/p>\n

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Housing<\/strong><\/h2>\n

Giraffes are popular exhibit animals with specialized housing needs.8<\/a>,14<\/a><\/sup> Giraffes are usually maintained in large paddocks outdoors. Fences do not need to be high because giraffes are reluctant to step over barricades. Indoor facilities are separated into stalls (Fig 10). Several females can be housed together, however males should be separated. Typically, only one male is kept with a herd since bulls may fight for dominance. In temperate climates, indoor facilities should be heated to 18-24\u00baC (65-75\u00baF) and outdoor access should be restricted at subzero temperatures.5<\/sup><\/a> Indoor housing should also provide dry, nonslip flooring with adequate drainage.5<\/a>,13<\/a><\/sup> Soft flooring may promote hoof overgrowth, therefore giraffes should be encouraged to walk on abrasive surfaces, such as brushed concrete.5<\/sup><\/a> Some zoos cover the floor with straw or shavings, while others use coarse gravel to provide traction and wear.5<\/sup><\/a> To reduce the risk of injury<\/a> from falls or entrapment of the neck or ossicones, careful consideration should be given to the placement of fencing, trees, chains or pulleys, hay racks, and enrichment items.13<\/a>,14<\/a><\/sup><\/p>\n

\"Indoor<\/a>

Figure 10<\/b>. Indoor giraffe (Giraffa<\/em> spp.) stall at the London Zoo. Of course giraffe house doors should ideally be high. Although giraffes can learn to lower their heads to walk through doors that are only slightly higher than their withers, they often will not do so when stressed, which could lead to injury.5<\/sup><\/a> Photo: Karen Roe\/Flickr Creative Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Selective browsers <\/strong><\/h2>\n

Giraffes preferentially select fresh leaves and buds high in protein (>20%). Free-ranging animals primarily feed on Acacia<\/em> spp.5<\/sup><\/a> Daily browse is a critical part of the captive diet for both nutritional and behavioral reasons (Fig 11).5<\/a>,13<\/a>,17<\/a><\/sup> Zoo giraffes are also offered free-choice alfalfa hay and formulated foods to meet dietary requirements.5<\/a>,13<\/a><\/sup><\/p>\n

\"Browse<\/a>

Figure 11<\/b>. Giraffes (Giraffa<\/em> spp.) in captivity should be offered low-starch browse on a daily basis to meet both nutritional and behavioral needs. Photo: Dani-Rae Law via Flickr Creative Commons. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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Manual restraint<\/strong><\/h2>\n

Giraffes are extremely agile and can kick in any direction with all four legs.5<\/sup><\/a> The head can also be used as a battering ram. Chutes or squeezes can be used in conditioned giraffes for minor procedures, such as venipuncture and simple hoof trims (Fig 12).5<\/sup><\/a><\/p>\n

\"Venipuncture<\/a>

Figure 12<\/b>. Jugular venipuncture in a giraffe (Giraffa<\/em> spp) restrained in a chute. Photo: Dr. Adrian Mutlow. Click image to enlarge<\/em>.<\/small><\/p><\/div>\n

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