Grazers - Biodiversity for a Livable Climate

Featured Creature: Giraffes

What animal, despite having the same number of vertebrae, has a neck longer than the average human, has spot patterns as unique between individuals as our fingerprints, and despite their gentle appearance, can kill lions with a karate-style kick!?

A tower of Reticulated giraffes (*G. reticulata*)
Image credit: Bird Explorers via iNaturalist (CC-BY-NC)

Some might say this is quite the… tall order for my very first Featured Creature profile! (Hold the applause!)

One of my earliest memories regarding these unique icons of the African savanna was when I was around five years old. My parents and I were visiting the Southwick Zoo in Mendon, Massachusetts, when we came upon the giraffe enclosure. One of these quiet, lanky creatures lowered its head across the fence bordering the enclosure, and licked my dad on the face with its looooong, black tongue! Once the laughter had died down, a flood of questions rushed into my head:

Why DOES the giraffe have such a long neck?

How do they sleep at night?

And what’s the deal with those black tongues?

A Tall-Walking, Awkwardly-Galloping African Animal

Their scattered range in sub-Saharan Africa extends from Chad in the north to South Africa in the south, and from Niger in the west to Somalia in the east. Within this range, giraffes typically live in savannahs and open woodlands, where their food sources include leaves, fruits, and flowers of woody plants. Giraffes primarily consume material of the acacia species, which they browse at heights most other ground-based herbivores can’t reach. Fully-grown giraffes stand at 14-19 feet (4.3-5.7 m) tall, with males taller than females. The average weight is 2,628 pounds (1,192 kg) for an adult male, while an adult female weighs on average 1,825 pounds (828 kg).

A giraffe’s front legs tend to be longer than the hind legs, and males have proportionally longer front legs than females. This trait gives them better support when swinging their necks during fights over females.

Giraffes have only two gaits: walking and galloping. When galloping, the hind legs move around the front legs before the latter move forward. The movements of the head and neck provide balance and control momentum while galloping. Despite their size, and their arguably cumbersome gallop, giraffes can reach a sprint speed of up to 37 miles per hour (60 km/h), and can sustain 31 miles per hour (50 km/h) for up to 1.2 miles (2 km).

Herd of giraffes running in Tanzania, Africa

When it’s not eating or galavanting across the savanna, a giraffe rests by lying with its body on top of its folded legs. When you’re 18 feet tall, some things are easier said than done. To lie down is something of a tedious balancing act. The giraffe first kneels on its front legs, then lowers the rest of its body. To get back up, it first gets on its front knees and positions its backside on top of its hind legs. Then, it pulls the backside upwards, and the front legs stand straight up again. At each stage, the individual swings its head for balance. To drink water from a low source such as a waterhole, a giraffe will either spread its front legs or bend its knees. Studies involving captive giraffes found they sleep intermittently up to 4.6 hours per day, and needing as little as 30 minutes a day in the wild. The studies also recorded that giraffes usually sleep lying down; however, “standing sleeps” have been recorded, particularly in older individuals.

Cameleopard

The term “cameleopard” is an archaic English portmanteau for the giraffe, which derives from “camel” and “leopard”, referring to its camel-like shape and leopard-like coloration. Giraffes are not closely related to either camels or leopards. Rather, they are just one of two members of the family Giraffidae, the other being the okapi. Giraffes are the tallest ruminants (cud-chewers) and are in the order Artiodactyla, or “even-toed ungulates”.

A giraffe’s coat contains cream or white-colored hair, covered in dark blotches or patches which can be brown, chestnut, orange, or nearly black. Scientists theorize the coat pattern serves as camouflage within the light and shade patterns of the savannah woodlands. And just like our fingerprints, every giraffe has a unique coat pattern!

The tongue is black and about 18 inches (45 cm) long, able to grasp foliage and delicately pick off leaves. Biologists thinks that the tongue’s coloration protects it against sunburn, given the large amount of time it spends in the fresh air, poking and prodding for something to eat. Acacia giraffes are known for having thorny branches, and the giraffe has a flexible, hairy upper lip to protect against the sharp prickles.

Both genders have prominent horn-like structures called ossicones, which can reach 5.3 inches (13.5 cm), and are used in male-to-male combat. These ossicones offer a reliable way to age and sex a giraffe: the ossicones of females and young are thin and display tufts of hair on top, whereas those of adult males tend to be bald and knobbed on top.

An elderly adult male Masai giraffe at the Franklin Park Zoo, Boston, Massachusetts
Image credit: Sienna Weinstein

There is still some debate over just why the giraffe evolved such a long neck. The possible theories include the “necks-for-sex” hypothesis, in which evolution of long necks was driven by competition among males, who duke it out in “necking” battles over females, versus the high nutritional needs for (pregnant and lactating) females. A 2024 study by Pennsylvania State University found that both were essentially acceptable! Check out the graphic below for a good visualization.

A graphic summarizing the evolution of the giraffe’s body based on gender needs
Image credit: Penn State University, CC-BY-NC-ND 4.0

A Flagship AND Keystone Species

Alongside other noteworthy African savanna species, such as elephants and rhinoceroses, giraffes are considered a flagship species, well-known organisms that represent ecosystems, used to raise awareness and support for conservation, and helping to protect the habitats in which they’re found. As one of the many creatures that generate public interest and support for various conservation efforts in habitats around the world, giraffes have a significant role.

Giraffes, like elephants and rhinos, are also classified as a keystone species–one that plays a crucial role in maintaining the health and diversity of their native ecosystems, as their actions significantly impact the environment and other species. What is it that giraffes do that impacts their local ecosystems and environment? By browsing vegetation high up in the trees, they open up areas around the bases of trees to promote the growth of other plants, creating microhabitats for other species. In addition, through their dung and urine, they help distribute nutrients throughout their habitat. Some acacia seedlings don’t even sprout and grow until they’ve passed through a giraffe’s digestive system! By protecting giraffes, we also contribute to protecting other plant and animal species of the African savanna and open woodlands!

The Life We Share

The woodlands and grasslands where giraffes live are shaped in part by those long necks and unique feeding habits. As they browse high in the canopy, they open up space for other plants and animals to thrive. These ecosystems aren’t something we built, they’re something we’re lucky to witness. And if we have a role to play, maybe it’s simply to make sure our presence doesn’t undo the work that nature is already doing so well.

Sienna Weinstein is a wildlife photographer, zoologist, and lifelong advocate for the conservation of wildlife across the globe. She earned her B.S. in Zoology from the University of Vermont, followed by a M.S. degree in Environmental Studies with a concentration in Conservation Biology from Antioch University New England. While earning her Bachelor’s degree, Sienna participated in a study abroad program in South Africa and Eswatini (formerly Swaziland), taking part in fieldwork involving species abundance and diversity in the southern African ecosystem. She is also an official member of the Upsilon Tau chapter of the Beta Beta Beta National Biological Honor Society.

Deciding at the end of her academic career that she wanted to grow her natural creativity and hobby of photography into something more, Sienna dedicated herself to the field of wildlife conservation communication as a means to promote the conservation of wildlife. Her photography has been credited by organizations including The Nature Conservancy, Zoo New England, and the Smithsonian’s National Zoo and Conservation Biology Institute. She was also an invited reviewer of an elephant ethology lesson plan for Picture Perfect STEM Lessons (May 2017) by NSTA Press. Along with writing for Bio4Climate, she is also a volunteer writer for the New England Primate Conservancy. In her free time, she enjoys playing video games, watching wildlife documentaries, photographing nature and wildlife, and posting her work on her LinkedIn profile. She hopes to create a more professional portfolio in the near future.

Dig Deeper

Featured Creature: Sloth

What creature used to live on the ground but now hangs in trees, has hair that grows in the opposite direction than most mammals, and turns green because of the algae that thrives in their fur?

The Sloth! (Folivora)

Hoffman’s Two-toed Sloth, *Choloepus hoffmanni*
(Image Credit: Andrae Scholz via iNaturalist (CC-BY-NC))

Would you be surprised if I told you that sloths aren’t lazy, but slow and careful?

Sloths have been labeled as some of the laziest animals due to their slow movements and the (unfair and misguided) assumption that they sleep all day. This belief isn’t helped by the fact that the word sloth literally means “laziness,” as does its common name in many other languages. But as we’ll learn, there’s a lot more to this creature than meets the eye, and their chill, methodical nature is actually a quite ingenious survival mechanism.

The six surviving species of sloths are categorized into two groups: Bradypus, the three-toed sloths, and Choloepus, the two-toed sloths. Even with this naming, all sloths have three toes on their back limbs – whereas two-toed sloths only have two digits on their front limbs. Both groups descend from ancestors that were mostly terrestrial (meaning they lived on the ground) that existed about 28 million years ago. Some of them reached sizes rivaling those of elephants! The sizes of modern sloths vary, with three-toed sloths typically ranging from 60-80 cm in length (24-31 inches) and weighing between 3.6-7.7 kg (8-17 lbs), while two-toed sloths can be slightly larger, particularly in weight.

Found in the tropical rainforests of Central and South America, you can identify them by their rounded heads, tiny ears, and a facial structure that makes them look like they’re always smiling. They have stubby tails and long limbs ending in curved claws that, historically used for digging, now work with specialized tendons and a grip strength that is twice as strong as a humans to climb tree trunks and hang upside down from branches effortlessly. It is believed that over time, sloths evolved into a suspensory lifestyle to have easy access to plentiful food (mainly leaves), stay safe from predators (like jaguars and ocelots), and conserve energy.

Leafy Lunches

Sloths have a very low metabolism, meaning their bodies take quite a while to turn food into energy, thus the characteristically sluggish pace. Sloths move at about 4 yards per minute, and in an entire day, they may cover only around 120 feet, which is less than half the length of a football field. These languid movements are the reason why sloths can survive on a relatively low-energy diet, like leaves. While three-toed sloths are almost entirely herbivorous, two-toed sloths have an omnivorous diet that includes insects, fruits, and small lizards.

Even though leaves are the main food source for sloths, they provide very little nutrients and don’t digest easily. These lethargic tree-dwellers have large, slow-acting, multi-chambered stomachs that work for weeks to break down tough leaves. In fact, up to two thirds of a well-fed sloth’s body weight consists of the contents of its stomach. What other animals can digest in hours takes sloths days or weeks to process! Due to their slow digestion, sloths descend every week or so to defecate on the ground. Why exactly they do this is still a mystery to scientists, especially because sloths are at much more risk to predators on the ground.

Did you know that baby sloths learn what to eat by licking the lips of their mother?

Sloths, Moths, and Little Green Friends

Perhaps one of the most fascinating things about our slow-moving friends is what lives in their fur. Believe it or not, it’s a miniature world! Acting as a mobile home for a variety of different insect, fungi, and microbial species, sloths are, in fact, thriving ecosystems. But first, let’s set the scene.

Sloth fur grows in the opposite direction than it does on other animals. Normally, hair will grow towards the arms and legs, but because sloths spend so much of their lives upside down in the canopy with their limbs above their bodies (eating, sleeping, even giving birth hanging upside down), their fur grows away from their extremities and towards their bodies, giving them protection from the elements.

The layered and grooved structure of sloths’ shaggy coat is the perfect environment to host many species of commensal beetles, mites, moths, fungi, as well as a symbiotic green algae. While the sloths don’t directly consume and gain nutrients from the algae (legend held for many years that sloths were so lazy, they’d rather eat the algae off their back than search for food), its presence helps protect the sloths from predators by aiding in their camouflage, hiding them from predators like harpy eagles.

A Slow but Important Presence in the Rainforest

Sloths are an integral part of tropical rainforest ecosystems. They regulate plant growth through their consumption of leaves, provide a unique habitat for smaller organisms like algae and moths in their fur, and contribute to nutrient cycling by depositing their feces on the forest floor, dispersing seeds and fertilizing new plant growth.

Some species of sloths are at risk because of deforestation, contact with electrical lines, and poaching and animal trafficking. The health of these creatures is wholly dependent on the health of the tropical rainforest. If their habitat begins to deteriorate, sloths are forced to live elsewhere in places that cannot support healthy populations.

Luckily, The World Wildlife Fund (WWF) works with communities, governments, and organizations to encourage sustainable forestry, and collaborates to expand areas of forests under responsible management. WWF has worked with the Brazilian government since 2003 on the Amazon Region Protected Areas (ARPA) initiative, helping it become one of the largest conservation projects in the world. Not to mention, The Sloth Institute of Costa Rica is known for caring, rehabilitating, and releasing sloths back into the wild.

Northern Atlantic Forest Three-toed Sloth, *Bradypus variegatus*
(Image Credit: Kevin Araujo via iNaturalist (CC-BY-NC))

More than meets the eye

While sloths are well-known for their slow-moving pace and are labeled as lazy, to believe that that is the only notable thing about them is largely inaccurate. Similar to how judging a person based on one aspect of their personality is not an accurate judgment of their character, judging sloths based on their sluggishness is not an accurate judgment of sloths as creatures. It overlooks how they’ve adapted from life on the ground to life in the trees, how they use their muscles and long claws to hang upside down and save a ton of energy, their role as ecosystem engineers, how they create habitats for other organisms, and how they help maintain the health of the forest.

So the next time we come across a creature – whether in the wild or at a sanctuary – we might ask, “What else can this creature do?”

Abigail Gipson is an environmental advocate with a bachelor’s degree in humanitarian studies from Fordham University. Working to protect the natural world and its inhabitants, Abigail is specifically interested in environmental protection, ecosystem-based adaptation, and the intersection of climate change with human rights and animal welfare. She loves autumn, reading, and gardening.

Sources and Further Reading:

Featured Creature: Nilgai

Which creature is the largest Asian antelope, considered sacred to some and pest to others?

The Nilgai!

This fascinating four-legged friend could be described by a whole host of leading questions, depending on which notable features we want to emphasize. Elizabeth Cary Mungall’s Exotic Animal Field Guide introduced the nilgai with the question “What animal looks like the combination of a horse and a cow with the beard of a turkey and short devil’s horns?”

Personally, I find the nilgai much cuter than that combination might suggest, but it may all be in the eye of the beholder. The name ‘nilgai’ translates to ‘blue cow’, but the nilgai is really most closely related to other antelopes within the bovine family Bovidae. Mature males do indeed have a blue tint to their coat, while calves and mature females remain tawny brown in color.

As their physiology suggests, nilgai are browsers that roam in small herds, with a strong running and climbing ability. I encountered them in the biodiversity parks of New Delhi and Gurgaon, where efforts to rewild the landscape to its original dry deciduous forest make for ideal stomping grounds for the nilgai.

Prolific Browsers

Indigenous to the Indian subcontinent, the nilgai is at home in savanna and thin woodland, and tends to avoid dense forest. Instead, they roam through open woods, where they have room to browse, feeding on grasses and trees alike. They’re considered mixed feeders for that reason, and will adjust their diet according to the landscape. Nilgai are adept eaters, standing on their hind legs to reach trees’ fruits and flowers and relying on their impressive stature (which ranges from 3 to 5 feet, or 1 to 1.5 m, at the shoulder) to get what they need.

Photo from Wikipedia
(By Akkida, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=34508948)

Like other large herbivores, nilgai play an important role in nutrient cycling and maintaining the ecosystems they’re a part of. In this case, that looks like feeding on shrubs and trees to keep woodlands relatively open, as well as dispersing seeds through their dung. One 1994 study noted the ecological value of the nilgai in ravines lining the Yamuna River, where the nitrogen contained in their fecal matter can make a large difference in soil quality, particularly in hot summer months.

These creatures actually defecate strategically, creating dung piles that are thought to mark territory between dominant males. As a clever evasion tactic, these are often created at crossroads in paths through forest or savanna-scape, so that predators may not be able to trace the nilgai’s next steps so easily.

Photo from Wikipedia (By Bernard Gagnon – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=30634949)

Food webs for changing times

The natural predators of the nilgai once included the Bengal tiger and Asiatic lion, as well as leopards, Indian wolves, striped hyena, and dholes (or Indian wild dogs) which sometimes prey on juveniles. However, as deforestation, habitat loss and fragmentation, and development pressures change the face of the subcontinent, the ecological role of the nilgai has become more complicated. While their association with cows, a sacred animal in Hinduism, has widely prevented nilgai from being killed by humans, the relationship between people and nilgai is becoming more contentious.

Where nilgai lack their traditional habitat to browse, they turn to plundering agricultural fields, frustrating the farmers who work so hard to cultivate these crops. Farmers in many Indian states thus consider them pests, and the state of Bihar has now classified them as ‘vermin’ and allowed them to be culled.

Photo from Wikipedia (By Jon Connell – https://www.flickr.com/photos/ciamabue/4570527773/in/photostream/, CC BY 2.0)

There’s no place like… Texas?

Strangely enough, when I got inspired by my nilgai sightings in India and decided to learn more about these Asian antelopes, one of the first search results I encountered involved nilgai populations here in the US. Specifically in Texas, an introduction of nilgai in the 1920 and 30s has spawned a population of feral roamers. Accounts say that nilgai were originally brought to the North King Ranch both for conservation and for exotic game hunting, somewhat distinct priorities that regardless led to the same result, a Texas population that now booms at over 30,000 individuals.

In this locale, nilgai largely graze grasses and crops, as well as scrub and oak forests. Here hunters have no qualms about killing them, but some animal rights groups object, and popular opinion remains divided on whether such treatment is cruelty or, well, fair game.

These days, one concern is that a large nilgai population contributes to the spread of the cattle fever tick. Another concern remains about these grazers acting as ‘pests’ on agricultural land.

Fundamentally there is a question that lies at the heart of the nilgai’s fate, both at home in India and Bangladesh, where natural predators and original habitat have steeply declined, and abroad, where they weren’t a part of the original ecosystem at all: what do you do when an animal’s ecological role is out of balance?

In my view, there are no easy answers, but a familiar pattern we seem to uncover – that healthy ecosystems, where intact, harbor more complexity than we can recreate or give them credit for. Little by little, I hope we can support their conservation and resurgence.

By Maya Dutta

Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. She is the Assistant Director of Regenerative Projects at Bio4Climate.

Sources:
https://animalia.bio/nilgai
https://www.thedailybeast.com/nilgai-the-chimeric-beast-overrunning-texas-and-spreading-disease
https://en.wikipedia.org/wiki/Nilgai
https://www.britannica.com/animal/nilgai

Creature: Grazers