Rising threats against the world’s tallest animal; the Giraffe

Authors: Adam Mercer, Alejandro Sanchez, Catherine Tellez, Danielle Fitzwater

Introduction

Giraffes are one of those animals that seem like they’re right out of fiction. A horse-like body, a leopard print pattern on its skin, a neck unlike anything else, leg stilts more reminiscent of a bird than a mammal, and two stubby horns to quite literally top it all off. With these characteristics in mind and the fact that this is the tallest living creature in the world, it isn’t a wonder that the giraffe is such an iconic figure recognized throughout the world. The unique characteristics of the giraffe put their species in danger when they encounter anthropogenic threats that can drive them to extinction. 

An Iconic Species

Giraffes, Latin name Giraffa camelopardalis (meaning Giraffe Camel-leopard for any Latin enthusiasts) are a large mammal belonging to the Artiodactyla family, which roughly means “even-toed” hoofed animals. Though this family oddly also gave rise to dolphins and whales, the name is a little misleading (15). Male and female giraffes don’t look very different, though the males tend to be noticeably larger and taller. Giraffes have a wide geographic distribution but are mainly found in East Africa, Angola, and Zambia in southwestern Africa (8). They are herbivores and live in savannas, open woodlands, grasslands, and even desserts (10). Giraffes evolved their long necks to reach vegetation in trees that others cannot reach, rather than out of a love of neck ties (14). The horns on the heads of giraffes are called ossicones and are used for defense and display in addition to looking cute (11). The largest giraffe subspecies can reach a height of approximately 18.7 ft. when fully grown and weigh over 2,600 lbs for males and 1,800 lbs for females (11). These adults are big, and very few things can mess with a full-grown giraffe and live to tell about it.  However, these majestic anomalies of nature are a species listed as “vulnerable” due to ongoing threats affecting the species. Now if you don’t know what a giraffe looks like, they look like this.

Their diet varies throughout the year and is dependent on seasonal changes (9). During the wet seasons, giraffes eat shrubs, deciduous trees (meaning they shed their leaves annually) and vines. During the dry seasons, their diet changes to evergreen leaves, which don’t wilt away from the lack of rain (9). Giraffes have fission-fusion social networks in which they change the size and composition of their groups as a response to environmental conditions (7). This means that the herds will split up if there doesn’t seem to be enough food or water to keep everyone in the group fed. The changes in food abundance and quality as a result of climate change have been observed to exacerbate problems in tandem with the anthropogenic threats posed to giraffes by humans. Global warming, the main driver of climate change, is one of the main threats against giraffes. Some organisms seem to be in an arms race with climate change, trying to acclimate and adapt to the changes that are occurring in their specific climatic niches. Giraffes are one example of a species trying to acclimate or adapt to conditions caused by climate change. However, it is not the only threat they face. Giraffes also face anthropogenic threats (meaning humans are responsible), like overhunting and habitat loss that lead to local extinctions and cause shifts in population niches (4).

Anthropogenic threats giraffes encounter

The effects of anthropogenic encroachment, climate change, and ecosystem isolation all play substantial roles in the threats facing giraffes. In a recent study, researchers found that habitat fragmentation as a result of human development reduces the viable area of land that can be inhabited by multiple herbivorous species, leading to competition for resources (6). The siphoning of water sources for industrial use and agriculture has led to reduced water levels in lakes and less vegetation to forage. This comes at the cost of other herbivore species, more so than full-grown giraffes, since giraffes are tall enough to reach vegetation others cannot. However, the most damaging threat to giraffe populations is drought (6). In years of El Nino, extreme drought left giraffe populations decimated due to the slowed growth of young giraffes that died due to lion predation, causing the giraffe population to decline from 153 to 62 individuals between 1995 to 2002 (6). In the rise of more extreme El Nino events with the warming climate, this threat is becoming even more prevalent. This indicates that climate change and human influence can indirectly hurt ongoing populations over time.

Giraffe population structures are impacted by climate change and human actions related to land-usage. In an article titled “Seasonal changes in the social structure of giraffe” by Wolf et al., the authors explore the dynamic fission-fusion social structures within giraffe populations and how they change seasonally. Although living in a group provides benefits like protection from predators and increased access to mates, it can consequently also cause competition for mates and resources among members (7). Using coat patterns, researchers identified and monitored individual giraffes on a private game reserve in Kwazulu-Natal, South Africa. They gathered data on the number of giraffes per group, the number of single individuals, and the sex composition of the groups. Single females were more common during the wet season while the number of multi-male groups greatly increased during the dry season. Both multi-female and multi-male groups increased during the dry season (7). Increased grouping as a response to longer dry seasons may lead to higher competition within the groups or other complications that the giraffes normally would not have to face.

Researchers have also focused on giraffe social networks in areas of contrasting human activity and lion density. In their study, two sets of populations of Rothschild’s giraffes south of Nakuru, Kenya were examined to determine if humans and lions have an effect on social networks of giraffes. Social networks are important to giraffes because a strong bond between calves and other adult giraffes increases their survival rate and decreases their aggression towards others of their kind (5). One population of giraffes inhabited an area of high human and lion density, and the other population area had low human density and no lion population. To eliminate environmental factors, the two locations of the giraffe populations were extremely similar in topography (the arrangement of the natural and artificial physical features of an area), climate, and variation of flora and fauna. The social interactions of both populations were observed for nine months to determine the bond strength between individual giraffes. The results indicated that when giraffes are among a high predation group or in close proximity to humans with high activity, social networks weaken, putting them at risk (5).

Land modifications are worsened through climate change and affect populations

Changes in species climatic niches resulting from human-induced range contractions like habitat loss and overhunting have a significant influence on Species Distribution Models (SDM) (4). SDMs are used for conservation biogeography which makes predictions of how the effects of climate variations will affect biodiversity in a given area. Researchers wanted to find out if the contraction of the giraffe climatic niche by a human-induced action influences the predictions on SDMs in predicted climatic scenarios (4). This was done by creating models with current data and data that dates back to the 1970s. They were able to see how species distribution has changed throughout time. Essentially, drought conditions brought about by events like after El Nino, creates a positive feedback loop that ultimately affected levels of vegetation, predation, and eventually individuals distribution of giraffes across the landscape based on available resources (6). The contemporary models reveal that giraffe populations are going to be affected severely since resources are not as abundant in that region anymore. Giraffes are scattered around and as humans continue to hunt and modify the land the spatial distribution could potentially make it hard for giraffes of that population to mate (4). This can cause multigenerational effects that affect physiology and how giraffes interact. The effects of human industry and climate change have been breaking down the level of social rearing. In recent years this has led to high predation levels of many young giraffes and also plays a major role in the species-wide decline. 

Conclusion

Climate change may produce changes in seasonal giraffe group structure due to its effects on wet and dry seasons. Human land-usage is also invading into wildlife territory, which indicates there is an impact to the giraffe's social network. Instead of worrying about only seasonal changes, giraffes social networks should be considered as well. There are many variables that are affecting giraffe social structures and impact their survival rate. While mostly grim, there are some options to help the species recover. Things like the use of sustainable technologies can lessen human impact of waterways and vegetation. Smart city design can be used to create natural bridges across habitats and prevent cutting off populations. Larger wildlife preserves can be set up to sustainably coexist without humans disrupting the ecosystem. Another alternative is for humans to re-evaluate how much they care about nature and animals. There could be laws enacting restrictions to construction, preventing developments from getting too close to a vulnerable species habitat. Hopefully, with fewer disruptions and more land to interact with, giraffe young can successfully reach adulthood in the safety of the herd, returning the populations to the path to recovery. 

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