The scent of the reticulated giraffe (Giraffa camelopardalis reticulata)

The giraffe (Giraffa camelopardalis) emits a scent that can be detected by humans over considerable distances. Dichloromethane extracts of hair samples from adult male and female reticulated giraffes (G. c. reticulata) were analysed by gas chromatography–mass spectrometry. Two highly odoriferous compounds, indole and 3-methylindole, identified in these extracts appear to be primarily responsible for the giraffe’s strong scent. Other major compounds identified were octane, benzaldehyde, heptanal, octanal, nonanal, p-cresol, tetradecanoic acid, hexadecanoic acid, and 3,5-androstadien-17-one; the last compound has not previously been identified from a natural source. These compounds may deter microorganisms or ectoparasitic arthropods. Most of these compounds are known to possess bacteriostatic or fungistatic properties against mammalian skin pathogens or other microorganisms. The levels of p-cresol in giraffe hair are sufficient to repel some ticks.     

Assessment of contrafreeloading preferences in giraffe (Giraffa camelopardalis)

Contrafreeloading is an intriguing phenomenon in which animals will work to obtain resources, such as food, when the same resource is simultaneously freely available. Multiple hypotheses exist for why animals might choose to contrafreeload. In this study, we assessed preferences for contrafreeloading in giraffe at the Bronx Zoo to determine whether they actually preferred to contrafreeload or were simply demonstrating a willingness to contrafreeload. Food was presented in a range of distributions between an easily accessed feeding device and a more challenging one and the giraffes’ feeding behavior at these two types of feeding devices was recorded. As the experiments progressed, more giraffe used these more challenging feeders. There was significant individual variation in the expression of preference for contrafreeloading and willingness to contrafreeload. Individual, phase of the experiment, and an interaction between these factors were significant predictors of challenge feeder use. Three foraging strategies emerged among the giraffe that we termed “freeloaders,” “contrafreeloaders,” and “opportunists.” The results of this study demonstrate that multiple indices of preference are necessary when assessing contrafreeloading behavior, and that giraffe are affected to different degrees by the factors that stimulate contrafreeloading. These results may shed light on why different individuals use complex feeding enrichment devices to varying extents.     

Characterization of 16 microsatellite marker loci in the Maasai giraffe (Giraffa camelopardalis tippelskirchi)

Sixteen polymorphic microsatellite markers with an average allele size of k = 4.3 are identified from a genomic plasmid library constructed for giraffe (Giraffa camelopardalis ssp.). Primer sequences and marker data are reported in tabular form. The markers were screened in a population of 25 Maasai giraffe (G. c. tippelskirchi) collected near the Athi River, Kenya. The average observed heterozygosity for each marker was 0.36 with an average expected heterozygosity of 0.535. Hardy–Weinberg deviations are reported from this population, which is suspected to be inbred. The markers will be used to screen the captive giraffe population for subspecific or hybrid classification.     

A review of the social behaviour of the giraffe Giraffa camelopardalis: a misunderstood but socially complex species

1. Until around 2000, giraffe Giraffa camelopardalis were believed to have no social structure. Despite a resurgence of interest in giraffe behaviour in around 2010, most studies are of isolated populations, making it difficult to draw general conclusions. Although it is now well established that giraffe social organisation is non-random, there is little consensus as to what influences preferred and avoided associations or the underpinning mechanisms.
2. We test two hypotheses: first, giraffe have a complex cooperative social system, exhibited by 1) stable groups of females, 2) offspring that stay in their natal group for part or all of their lives, 3) support by non-mothers in rearing young, and 4) non-reproductive females in the group; and second, giraffe form matrilineal societies, evidenced by 1) male dispersal, 2) female philopatry, 3) assistance in raising or protecting offspring, and 4) individual benefits gained from social foraging.
3. We reviewed 404 papers on giraffe behaviour and social organisation; captive studies were included where they supplemented information from free-living populations.
4. We show that giraffe exhibit many of the features typical of mammals with complex cooperative social systems and matrilineal societies. However, the social complexity hypothesis posits that such species also require complex communication systems to regulate interactions and relations among group members; giraffe communication systems are poorly understood.
5. Quantifying the fitness and survival benefits of the giraffe’s social organisation is necessary to ensure its long-term survival. Giraffe numbers have declined by 40% since 1985, they have been declared extinct in seven (possibly nine) countries and are listed as Vulnerable by the International Union for Conservation of Nature. We identify research areas that will advance our understanding of giraffe behaviour and conservation requirements.

     

Rothschild’s giraffe Giraffa camelopardalis rothschildi (Linnaeus, 1758) in East Africa: A review of population trends,taxonomy and conservation status

Giraffe populations have suffered a 40% decline in the past thirty years, making them a new priority for conservation and there are considerable uncertainty and disagreement over the taxonomic classification of giraffes. Consequently, there has never been a more critical time to fully understand the global population size and distribution of all giraffe subspecies. The Rothschild's giraffe Giraffa camelopardalis rothschildi (Linnaeus, 1758) is arguably one of the most imperilled giraffe subspecies. Once widespread across southern Sudan, Uganda and Kenya, the Rothschild's giraffe is now confined to a few, isolated and enclosed populations throughout Kenya and Uganda, with only one natural population remaining. Information about Rothschild's giraffe population size, distribution, and conservation history is patchy, and confined to recondite or inaccessible resources. Here, I present a review of taxonomy, distribution, conservation status and population size of the Rothschild's giraffe and present the most recent estimate of population sizes based on direct census data. Although the Latin name affixed to Rothschild's giraffe is subject to discussion, continued reference to this subspecies as G. c. rothschildi is strongly recommended.     

Applying computer‐aided photo‐identification to messy datasets: a case study of Thornicroft's giraffe (Giraffa camelopardalis thornicrofti)

Digital photography enables researchers to rapidly compile large quantities of data from individually identifiable animals, and computer software improves the management of such large datasets while aiding the identification process. Wild‐ID software has performed well with uniform datasets controlling for angle and portion of the animal photographed; however, few datasets are collected under such controlled conditions. We examined the effectiveness of Wild‐ID in identifying individual Thornicroft's giraffe from a dataset of photographs (n = 552) collected opportunistically in the Luangwa Valley, Zambia from March to October 2009. We assessed the programme's accuracy in correctly identifying individuals and the effect of five image quality factors on identification success: blurriness, background type and complexity, amount of sky and the presence of other giraffe. The programme correctly identified individuals in 71.6% of photographs. Background complexity was the only significant variable affecting identification success and removing background imagery reduced identification error by 52.8% (from 28.4 to 13.4%). Our results indicate higher levels of error than previously reported for Wild‐ID. However, they also suggest the programme is an effective tool for quickly identifying individuals in large field datasets, especially if photograph backgrounds are removed beforehand and postanalysis visual verification is performed.     

Urinary steroid evaluations to monitor ovarian function in exotic ungulates: II. Comparison between the giraffe (Giraffa camelopardalis) and the Okapi (Okapia johnstoni)

Ovarian activity in the female giraffe was evaluated during the nonfertile ovarian cycle and during the terminal stages of gestation. Progesterone metabolites, in the form of pregnanediol-3-glucuronide (PdG), were measured in daily random urine samples collected from four adult parous giraffes. The follicular phase averaged 4.0 ± 0.1 days in length (N = 12; range 3–5 days) and peak PdG levels in the postovulatory period averaged 30.9 ± 1.7 ng/mg Cr (N = 12). PdG levels during the latter half of gestation greatly exceeded average luteal phase levels, which is in contrast to domestic ruminants. Prior to parturition, a marked decline in PdG excretion was evident, which may be useful for anticipating this event. These data serve to elucidate ovarian function in the mature female giraffe and to provide information concerning the physiologic role of certain anomalous ovarian structures. In addition, observed similarities in the pattern of PdG excretion during the nonfertile cycles of the giraffe and the okapi indicate similar underlying physiologic processes.     

Sleep‐related behaviors in zoo‐housed giraffes (Giraffa camelopardalis reticulata): Basic characteristics and effects of season and parturition

Despite increasing interest in the behavior of zoo animals, studies of nocturnal behavior of zoo animals are limited. In this study, we investigated the relationship between parturition, season, and the sleep‐related behaviors in captive reticulated giraffes to better understand the nocturnal life in giraffes. The subjects were two adult reticulated giraffes living in Kyoto City Zoo, Japan. Observations were made via an infrared camera that was mounted in the indoor enclosure between June 2007 and August 2009. We analyzed video clips that were recorded between 16:30 and 09:00 the next morning, over a total of 199 days. Sleep‐related behaviors were classified into two categories based on the posture of the giraffes; recumbent posture and paradoxical sleep. We also recorded the laterality of recumbent posture, which was coded based on the direction of the legs against the torso (right or left). Seasonal differences in sleep behaviors between summer and winter were observed in both individuals. They tended to start to lie down earlier in the winter than in the summer. Parturition also affected the behaviors as both individuals decreased the behaviors before and after the parturition of the female. Additionally, the female lay on her left side less frequently than her right when resuming a recumbent posture in the pre‐parturition period, while such laterality was not observed in the baseline and post‐parturition period. These results suggested that season and parturition are important factors for determining the sleep‐related behaviors in giraffes. Further studies are needed to understand how these changes in sleep affect other welfare parameters.     

An investigation of browsing enrichment,especially non-leaf foraging,on giraffes (Giraffa camelopardalis reticulata) at Kyoto City Zoo in Japan

Browsing enrichment may aid in developing species-specific behaviors for giraffes managed in zoos as a means of improving animal welfare. By nature, giraffes are tree-feeding animals, including tree bark, but the extent of food other than leaves as a form of browsing enrichment has not been well investigated. Therefore, to investigate the effectiveness of non-leaf foraging, three giraffes at the Kyoto City Zoo in Japan were observed for 228 h from May 2019 to February 2020. In conjunction with behavioral instantaneous sampling, tree use (landscape tree or enrichment branch) and plant part (leaves, twigs, or barks) were recorded by the 1-0 sampling method. There was no significant change in the foraging behavior on the leaves of enriched branches, nor was there any significant change in the foraging behavior of the giraffes, except for one animal in the deciduous phase. No significant changes were observed in rumination or other behaviors between the two phases. Although vegetation foraging behavior significantly decreased, except for one animal, dry hay foraging behavior significantly increased in all the animals during the deciduous phase. Some individuals also showed a significant increase in the foraging behavior for non-leafy parts of the enrichment branches (twigs and bark) during the deciduous phase. This suggests that in some tree species, giraffes forage on the bark and twigs to compensate for the loss of leaves during the deciduous phase, similar to feeding on hay or hay cubes as a substitute for tree leaves.     

Giraffe (Giraffa camelopardalis) social networks in areas of contrasting human activity and lion density

The adaptive value of close social bonds and social networks has been demonstrated in a variety of vertebrate taxa. While the effect of predators on populations is well established, disturbance by humans is increasingly being identified as affecting the behaviour and reproductive success of animals and can have significant impacts on their survival. We used a concurrent analysis of two adjacent giraffe Giraffa camelopardalis populations in Kenya to determine whether human activities and high predation affected their social networks. One study site was a premier tourist destination with a high volume of human activity in the form of tourist traffic and lodge infrastructure, alongside a high density of lions which preferentially prey on giraffe calves; the other was a private wildlife conservancy with minimal human activity and no lion population. Giraffes in both networks showed preferred associations and avoidances of other individuals, which were independent of space use. Bond strength was lower in the population exposed to high levels of human activity and lions, and the network had lower density and clustering, and shorter path lengths, suggesting that it was more fragmented. We suggest that human activity and predator density may influence the patterns of social interactions in giraffes and highlight the importance of understanding the impact of tourism and management on the survival and success of wild animal populations.     

Subendothelial fibrillar laminae in the carotid arteries of the giraffe (Giraffa camelopardalis)

Summary The endothelium in the carotid arteries of the giraffe lies on an extensive basement membrane complex that has a distinctly fibrillar component. Small electron-dense areas occur in the basal portion of the endothelium and normally in apposition to the fibrillar laminae of the basement membrane. These zones are believed here to constitute hemi-desmosomes where endothelial attachment may be most tenacious.     

Spatial ecology and habitat use of giraffe (Giraffa camelopardalis) in South Africa

The lack of long-term studies remains a limiting factor in understanding the home range, spatial ecology and movement of giraffes. We equipped eight giraffes with GPS satellite units and VHF capacity, which were built in to the collars for the remote collection of data on their movements and home ranges over two years on Khamab Kalahari Nature Reserve (KKNR) within the Kalahari region of South Africa. Giraffe numbers in KKNR dropped from 135 individuals to 111 in just five years, revealing the lack of knowledge about their required habitat needs, space use and diet. With over 1000 km² available for roaming within the reserve, habitat selection, principle and preferred food species played a significant role in home range size and overlap between individuals. These giraffes used an average annual home range of 206 km² (20 602 ha) as calculated by a 95% minimum convex polygon (MCP) with a standard deviation core home range calculated by a 50% MCP of 10.1 km² to satisfy their annual needs for survival and reproduction in their preferred vegetation. In the wet, hot season (summer: December–February) when food was abundant, giraffes frequented smaller areas (average 177 km²), while in the dry, cool season (winter: June to August) the mean home range size increased to approximately 245 km². Rainfall influenced spatial distribution since it determined vegetation productivity and leaf phenology. The different seasons influenced giraffe movements, while different vegetation types and season influenced their home range size. Season and food availability also influenced home range overlap between different giraffe herds. Home range overlap occurred when giraffes were forced to roam in overlapping areas during the dryer months when the winter deciduous nature of the majority of the tree species resulted in lower food availability. In winter, the overlap was approximately 31% and in autumn approximately 23%. During the wet and warmer months, overlapping was 15% in summer and 19% in spring, respectively. The percentage of time spent in different vegetation type areas was influenced by the abundance of the principal food species of that plant community. It is thus concluded that the movements of giraffes were primarily influenced by a combination of environmental factors such as season, rainfall and vegetation density.     

Structure and sympathetic innervation of the intracranial arteries in the giraffe (Giraffa camelopardalis)

Fluorescence histochemistry discloses that the carotid rete mirabile in the giraffe has a poor sympathetic innervation. In contrast, the efferent artery of the rete (internal carotid artery) and the cerebral arteries show moderate sympathetic innervation. A certain degree of regional variability was noted in which the rostral arteries (anterior and middle cerebral) receive more sympathetic nerves than the caudal (posterior communicating and basilar) arteries. The sympathetic nerves on the giraffe cerebral vessels may constitute part of a host of mechanisms by which regional blood flow to the brain is regulated. Conversely, the paucity of sympathetic innervation of the carotid rete mirabile may indicate that this structure does not play an active role in vasoconstrictor responses during postural changes of the head.     

Implications of closed ecosystem conservation management: the decline of Rothschild’s giraffe (Giraffa camelopardalis rothschildi) in Lake Nakuru National Park,Kenya

Giraffe were historically free‐ranging across most of sub‐Saharan Africa but are now most often confined to national parks, conservation areas, or private ranches. Five viable populations of Rothschild’s giraffe (Giraffa camelopardalis rothschildi) remain in protected areas in Kenya and Uganda. The viable population in Uganda is Murchison Falls National Park and the four populations in Kenya are Lake Nakuru National Park (LNNP), Ruma National Park, Giraffe Manor, and Mwea Natural Reserve. The Kenya Wildlife Service queried a rapid decline in LNNP giraffe numbers falling from 153 individuals (1995) to 62 individuals (2002) and the failure of that population to recruit young in those years. Significantly reduced browse options, inbreeding depression and preferential lion predation were considered as potential reasons for this trend. Population genetic parameter estimates derived from multilocus genotype analyses suggest that the LNNP population was in good genetic health with respect to the likelihood of inbreeding depression. The population decline coincided with the drought attributed to the 1994 El Niño. Possible dietary complications from highly concentrated tannin levels because of forced over consumption of the park’s declining acacia trees may have compromised young giraffe, making them easy and opportunistic prey for the park’s lion population.