Month: June 2019

Raka; Our Resident Crocodile

Raka; Our Resident Crocodile

The warm weather has touched the landscape across the Crocodile River and the cold-blooded reptilians slide onto the sandbanks from the cool water to bask in the sunlight. Like logs, the creatures lie almost lifeless, soaking up the rays of sunshine with beady-eyes seemingly staring blankly ahead. Raka; our resident crocodile, slides his huge body out of the water; he is the largest of the crocodiles on this stretch and dominates many of the smaller crocs in these waters.

On this particular morning one of our guests, Tommy Weys, captures some incredible photographs of Raka in his natural habitat. An unfortunate impala has wandered too close and has been snagged. A fully grown crocodile, like Raka, will consume 20% of his body mass in a single sitting. While his main diet subsists of fish, birds and smaller antelope, he is not impartial to establishing his dominance over the River by consuming smaller crocodiles as well.

Raka’s digestive system is a well-oiled machine; perfected through thousands of years of evolution. His jaw cannot move other than to clamp down or open up; he therefore swallows prey whole. The meal will reach his stomach, and be met by hydrochloric stomach acid, as well as small stones (that he swallows) which help him to grind the food; due to an inability to chew. What’s even more interesting about this process is that his blood plays a vital role. Crocodiles have a special valve in the heart muscle linked to an aorta leading directly to the stomach, which miss the lungs completely. The blood that travels along to the stomach is thus rich in carbon dioxide, a crucial component in releasing more acid into the stomach to disintegrate prey. The influx in gastric acid means that Raka can devour and digest his prey faster than any other animal and dissolve bones that have made it into his system.

On further inspection of this prehistoric creature paleo-biologists discovered that a crocodile’s bite force averages around 16 460 newton’s; 10 000 newton’s more than that of a lion or hyena. Interestingly though, the muscles to open the jaws are not nearly as strong, which is why conservationists recorded relocating crocs by simply holding their mouths shut.

This by no means diminishes a crocodiles dangerousness; Raka will stalk his prey from below the water’s surface and lash out quickly, clamping his strong jaws shut around his victim, before pulling it back into the water where it will drown. Once shut, his jaws act as a vice-grip and will be near impossible to open.

Raka may remain in the River whilst feasting on his prize, but this is to minimise his vulnerability to other crocodiles attempting to make a claim on his meal. Once he is satisfied, he drags his large body from the cool waters and basks in the sun to digest his food. The warm rays of the sun, and the special second aorta, work in conjunction to speed up digestion; without these tools Raka’s meal would putrefy in his stomach.

As he lies along the lazy Crocodile River, we begin to notice how he, and other crocodiles around him, seem to share the same vacant expression and wide-open mouth. This social behaviour is not at all random, and shares with us another glimpse into the marvellous evolution these creatures have experienced. We already know that crocodiles are cold-blooded, so their body temperature is directly proportional to that of their environment. Along the Crocodile River, temperatures can sky-rocket to over 40° Celcius and Raka, as well as his other scaly comrades, can overheat. Lying on the sandbanks with their mouths agape works similarly to that of a dog panting; the cool breeze ripples over the crocodile’s mouth and cools the blood flowing around its brain. Once thoroughly cooled, the crocodiles will return to the depths of the Crocodile River.

Each day we watch, eagerly, as crocodilians put on a show for the Lodge’s visitors along the meandering Crocodile River. Raka; our resident crocodile and fiercest mascot, makes regular appearances to amaze and instill a sense of wonder and awe in those lucky enough to behold him; a living, breathing dinosaur of the deep.

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Into The Biome

Into The Biome

Ngwenya Lodge sits comfortably along the winding Crocodile River on the South-Eastern boundary of the Kruger National Park. Being located at prime river-frontage, a major water source for Kruger wildlife makes Ngwenya well-positioned for year-round game-viewing. However, exploring the Kruger National Park on a self-drive or guided tour make for some incredible sightings; even more so when we delve into the biome of the Park and use it to our advantage for spectacular wildlife finds.

The Kruger National Park is classified as a majority Savanna biome.  This biome is characterised by grass-dominant ground coverage and woody vegetation as its upper layer; it also makes up approximately a third of South Africa’s overall biome. The upper layer of woody plants and trees almost never dominates the ground cover; this is attributed to the annual rainfall being relatively low in the area, recorded by 15 rainfall stations throughout the Kruger daily with a mean of 500mm each year. The region experiences its rainy season during the summer months; December, January and February with earth-shattering thunderstorms which are a sight to behold and often studied by international and national students. Wild grasses and shrubs make up the majority of the ground cover and provide an ample grazing ground for a range of antelope, while Acacia trees can be spotted in clusters or alone, and provide an excellent food source for larger game such as giraffe and elephant.

The Kruger National Park can be broken down into eight overlapping ecosystems, all forming a part of the greater Savanna biome, with the Central Grasslands providing the best example of the Savanna. The Northern Sandlands, Mopaneveld and Lebombo ecosystems fall further away from Ngwenya Lodge, but all make for interesting and unique game-viewing drives, should visitors wish to travel further into the Park.

Closer to home however, lies a multitude of ecosystems, each overlapping the next and providing a home to varied species, these are the; Riverine Bush, Thorn Thickets to the East, South Western Foothills, Mixed Broadleaf Woodlands and the Savanna Grasslands heading North.

  • Riverine Bush areas populate the River edges and can thus be found looking from an Ngwenya Lodge chalet patio, or lookout point. The foliage has near year-round access to water, creating a dense cover for species in the area. Commonly found on the floodplains are; elephant, waterbuck, crocodile and occasionally big cats and other game during the drier seasons when water is scarce.
  • Thorn Thickets are located towards the east along the Crocodile and Sabie Rivers and are characterised by large Acacia trees. During the summer months this thicket provides excellent cover for game seeking to wait out the heat of the day, and giraffe can often be found grazing from their favoured food source; the Acacia tree.
  • South Western Foothills make up the area enveloping Pretoriuskop and Berg-en-Dal to the West of Ngwenya Lodge. This area receives the highest rainfall within the Kruger Park and features incredible granite outcrops perfect for looking out over the Lowveld for a refreshment stop.

Nkumbe Lookout Point, Lower Sabie

  • Mixed Broadleaf Woodlands cover Skukuza and surrounds moving west into the National Park. The Woodlands are characterised by a range of Bushwillow trees and provide an excellent opportunity for guests wanting to spot predators. Regular sightings of lion, leopard and hyena are reported in this region.
  • Savanna Grasslands start north of the Sabie River and are a typical example of the Savanna biome; large open spaces covered in wild grasses and the occasional cluster of Acacia trees mark the area. This ample grassy vegetation means that large herds of antelope can be sighted here; zebra, wildebeest and rooibok cover the plains. The area also attracts many predators and cheetah put their speed to good use on the grasslands.

The Kruger National Park offers a wide range of ecosystems to explore and even more species to be sighted; a treasure trove of wildlife experiences. Journey into the biome and discover all this South African landscape has to offer.

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A Tribute to Elephants

A Tribute to Elephants

If you have ever found yourself seated on the Restaurant Deck, on a private patio or at one of the game-viewing hides along the Crocodile River at Ngwenya Lodge, then you know that this is elephant country. Herds can often be seen grazing along the river bank and sometimes wander so close to our hides that you can see the colour of their eyes. So how then, could we possibly resist this tribute to elephants? Elephants are such magnificent creatures and Ngwenya visitors are often awe-struck by their incredibly humble presence; Ngwenya takes a closer look with a few unexpected and interesting facts about Loxodonta africana:

  • Anatomy

Loxodonta Africana, more commonly known as the African Bush Elephant, is recognised as the largest land animal in the world. When a bull wanders close to the Lodge, crossing the River and heading up the embankments, guests come up-close-and-personal with these sentient beings and start to notice a number of fascinating attributes. For one, elephants most distinguishing feature: their trunks, are made up of over 40 000 larger muscles, all working together to provide the elephant with a flexible, multi-purpose appendage. These muscles can then be broken down into 150 000 fascicles; tiny internal muscles which could be likened with spokes or villi. To put this into perspective, humans have approximately 750 muscles in their entire bodies.

The trunk consists of muscle groups, nerves, and connective tissue but no bone. The elephant’s skeleton starts at the tail and ends with the skull. It is most fascinating to discover, and no real surprise, that an elephant’s leg bones consist of mostly bone; the bone marrow is subsequently replaced with a spongy, denser bone material. This allows the skeletal structure of the elephant to carry the heavy weight of its muscular structure; bone marrow is lighter and would not provide the necessary support for the animal. An elephant’s red blood cell production thus occurs, not in its bone marrow as with humans, but predominantly in the pelvis.

  • Talents

An elephant’s anatomy lends itself to a range of “talents”. For example, elephants have been recorded using their trunks for a number of incredible tasks; elephants most commonly make use of the proboscides, small finger-like extensions on the tip of the trunk, to grip and snatch foliage, much like a human would use their fingers to pick objects up. The trunk is not only used for feeding, or drinking water, but has an innate ability to smell. An elephant’s olfactory system works through the millions of receptor cells found inside the trunk; the message is relayed to the olfactory cortex found in the ventral lateral brain. This ability means the elephant is even better than a bloodhound and can smell water kilometres away!

Further use of the trunk has been documented as elephants “snorkel” across rivers or bodies of water; the animal will hold its trunk above the water level and wade along the river bottom so that it may continue to breathe.

The trunk is not the only interesting talent an elephant possesses. An elephant’s tusks are incisor teeth which protrude from the skull and grow to lengths of 2 metres. Fun fact: elephants are known to favour one tusk over another, similarly to that of humans being left- or right-hand dominant. Tusks are used for a number of tasks including; stripping bark off trees as a food source for fibre and defending themselves against predators or competition

  • Epidermis

The average elephant’s total skin mass is 900 kilogrammes and can be an inch thick in certain areas. The upper dermis of an elephant is supple and not rough as it may seem; it folds and creases across the mammals body, retaining moisture and keeping the elephant cool. This wrinkling is no accident; researchers at the University of Geneva and Swiss Institute of Bioinformatics presented new findings which suggest that the creases in an elephant’s skin are purposefully created. The tiny crevices and cracks are interconnected and offer higher water retention for evaporative cooling, and can hold more mud, in an effort to dissuade insects from biting and irritating these incredible creatures, than non-wrinkly skin. It has also recently been uncovered that elephant skin is not the same density or thickness across the board, but rather thins out in certain areas or “hotspots” such as the inner leg or over their ears. These locations are used to assist in cooling their blood; elephants are believed to have a certain degree of control over pumping their blood throughout their body and will push blood through the blood vessels near the surface of these “hotspots” to cool down.

  • Extremities

One such “hotspot” is an elephant’s ear; the skin over their ears is approximately a 10th of an inch. But this isn’t the only incredible feature of their ears; elephants have extraordinary hearing, too! The average elephant’s hearing range is between 12 hertz (hz) and 12 000 hz, nearly double the range of a human. In conjunction with their hearing, elephants also make use of their feet to receive communications from elephants further away. Through various studies, scientists have found that elephants communicate at a low-frequency level, much lower than the human ear can pick up, and that their communication pathways can be received and sent to elephants in an area as large as 100 square kilometres.

A large part of this evolutionary advantage can be attributed to an elephant’s feet and trunk. An infrasonic message will be sent through a series of low rumbles and vibrations from one elephant to another. The message travels through the ground and is picked up by the receiving elephant’s feet and trunk tip. Scientists discovered that a combination of bone condition, nerve endings and sensory receptors convey the message from their feet to the ossicles in an elephant’s ear. Elephants use this mean of communication to convey messages of: stress, mating calls and as a “tracker” when herds are spread far apart while searching for food and water during a drought.

  • Dynasty

During such times as drought, when families of elephants are scattered across the landscape finding food and water sources, the Matriarch will lead her herd to locations she has previously visited as a young elephant, or calf, where she remembers there being water or ample vegetation. This is just one of the incredible ways elephants display their connection to one another, and to their lineage. Usually an elephant herd consists of the Matriarch, her daughters and their offspring. At a certain age, the males will leave the group and form a loosely knitted bachelor group of their own. Interestingly, it has been documented that these elephant herds will continue to communicate with one another and stay connected across various families. Elephants display a level of empathy and connection between one another which is rarely observed in the animal kingdom; caring for each other’s offspring, sharing special bonds transcending distance and herds, and mourning for elephant members which have passed on.

Elephants
are incredible and magnificent creatures and are “awe-inspiring” to behold. 
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