DESERT ELEPHANT ANATOMY

Elephant Skin

The elephant’s hide is an incredibly tough, grey, wrinkled skin that covers the entirety of their body. It can be up to 3.8cm thick around the elephant’s neck, abdomen, or legs while being almost paper thing along their grown, eyes, or ears. Their skin is covered with a network of deep wrinkles as well as patches of sparsely distributed, stiff hair. The wrinkles have a two-fold purpose. Firstly, their depth acts as a moisture trap – water will therefore take longer to evaporate. Secondly, they increase the surface area of the skin which means there is more area available for heat to radiate off the elephant.

Similarly, the hairs act as mini ‘radiators’, further increasing the rate at which heat can dissipate from the elephant. The elephant’s skin is therefore another, incredible heat-regulating tool elephants have access to, alongside their ears.

Elephant Ears

Despite only accounting for 1% of their body weight, an elephant’s ears can account for up to 20% of their body surface. This, combined with the density of large veins and constant flapping, means that the elephants can cool the blood in their bodies by as much as 5 degrees Celsius.

Additionally, the size of an elephant’s skull and ears are well adapted to the perception of infrasonic sounds as low as 14Hz – humans are generally able to hear sounds only as low as 20Hz. Unfortunately, this means that higher ranges cannot be perceived by elephants – they are only able to hear sounds as high as 12kHz, compared to humans’ 20kHz. Lower wavelengths are better suited for long-distance communication, which is why elephants often communicate with their characteristic ‘rumble’.

Elephant Tusks

Elephant tusks are a set of two, elongated teeth that first appear when they are about two years old. They can be found in both male and female elephants, although male tusks are significantly longer and heavier than the females’.

Although their primary use appears to be digging for food or scraping the bark from trees in order to mark their territory, the tusks are often used for social rituals, self-defence, or displays of aggression and superiority – especially in males.

Interestingly, the tusks of desert elephants – such as those found in Namibia – are often more brittle than their savannah or forest counterparts. It is speculated that this is due to the poverty of water or minerals in their natural environment.

Elephant Feet

An elephant’s sole has a spongy, fat cushion that acts as a ‘shock absorber’. This allows them to walk over almost any type of terrain without pause or issue as the sole will smooth almost any object it encounters.

This also has the consequence that elephants are incredibly quiet walkers – especially for their size – as this ‘shock absorber’ will muffle most noises, evening the cracking of stones or the snapping of twigs.

Elephants, like cats, dogs, and hyenas are digitigrade in that they walk on their toes, and not their heels. However, an elephant’s heel does not rise off the ground as high as that of cats or dogs, and in that they are more similar to pigs or hippos.

An African elephant has four toes on their front feet and three toes on their hind feet. Further, the desert elephants have larger feet than their savannah or forest cousins. This is likely because they need to travel vast distances – often more than 70km – in search of water, across soft dunes and desert sand.

Elephant Tail

Adult elephants can have tails that are up to 1.5m long, and weigh as much as 11kg. Adults use their tails to guide younger elephants, whereas younger elephants might hold on to an older elephant’s tail in order to follow them.

However, the tail is usually used to swat away flies – a feat that requires as much torque as the engine of a sedan might. Or, in other terms, enough force to knock out a heavyweight boxer.  

What is the social structure of elephants?

Male and females usually live in separate, but overlapping worlds which join at the waterhole during feeding or breeding. While neither sex is territorial towards the other, they will each use specific ‘home areas’ throughout the year.

Elephants are a matriarchal society, which means the family units are usually led by the largest and oldest female of the group. Matriarchs are sources of knowledge for the herd, keeping the memories of food and water sources, and providing leadership.

The matriarch decides where the herd moves and when. During conflict or stress situations, the herd tends to cluster around the matriarch, and looks to her for defence or direction. The loss of a matriarch can severely disrupt the harmony of a herd. Her death will be mourned by members of the herd and it may take a long while before a new matriarch emerges to lead the family. These family groups occur in several variations:

·       Herds: these are family units between two and 30 elephants in size which include the matriarch, younger cows, and various calves. Herds are defensive family pacts where older cows defend younger cows and calves from non-family elephants and predators. Larger herds are also able to successfully dominate smaller herds, taking their food and water; essential during drought or famine. Desert elephants, however, tend to live in smaller family units of only two or three adults. This results in decreased pressure on resources, in a resource scarce environment.

 ·       Bond Groups: when families grow too large, some daughters or younger cows may decide to split off and form their own families. A bond group is a collection of such families that, while not a single unit anymore, are still connected by blood and memory. They often display elaborate greeting rituals when they meet at water holes, feeding grounds, or cemeteries.

 ·       Clans: families, bond units, and other groupings of elephants that share the same territory during dry seasons.

·       Bull Groups: these consist of adolescent and adult males. Male elephants are nudged from their maternal herd after reaching sexual maturity at around 14 years of age. They tend to spend their remaining time mostly alone, although when not in musth (in search for sexual partners), they may form smaller groups with other male elephants in a relaxed and social environment. Dominance in these groups is determined by an elephant’s size and age. During musth, male elephants may leave the group or risk losing their musth in the presence of a more dominant bull. The oldest male elephants tend to reduce their wanderings quite significantly and prefer to remain near easily accessible water and food sources.

Interestingly, research shows that the social structure in the elephants to the North-West of Namibia is more ‘bare-bones’ than those of elephants from other regions. Their social structure is more fluid, lacking the elaborate greeting rituals, behaviours, and social interactions of other herds.

Leadership is also less rigid than in other herds, with some groups not having a clear leader at all. The decline in traditional social structure among these elephants is possibly due to decades-long poaching in the 1970s and 1980s, which severely diminished the numbers of elephants roaming the North-West of Namibia.

Elephant Reproduction

Males have internal testicles; they lack an external scrotum. The elephant cow’s vagina opens downward and looks like a loose skin flap. Elephants have breasts, like humans, and not udders like cows. Their breasts are between their forelimbs on the ‘chest’ of the elephant and are only visible once the elephant has had her first pregnancy, until then male and female elephants look similar.

Females prefer more dominant – older, or stronger – males in musth. Usually this means males that are at least 35 years old that have higher testosterone levels than their counterparts. Bulls that are experiencing musth – an event that typically occurs only once a year – see increases in their testosterone up to 60 times their normal levels.

Often this results in increased aggression, territoriality, fighting, and competition – especially for females. The younger, less dominant males are denied the opportunity to mate by the older, stronger males – a behaviour thought to limit unsustainable population growth. The successful males then begin their search for a receptive female.

Females can start breeding once they reach puberty between 12 and 14 years of age. Much like humans, elephants also endure a menstrual cycle. Each cycle lasts between 13 to 18 weeks and sees a peak about halfway through during which the chance for pregnancy among elephants is highest.

One will often see male elephants in musth guarding the female elephants at the height of their cycle. The start of ovulation is known as estrus or being in heat and sees rapid increases in female sex hormones such as estrogen and progesterone.

Once a male has found a receptive female, they begin a protracted game of cat-and-mouse. The female will rub herself against the male and they may even entwine their trunks, before she runs away. The male must give chase and can consider himself successful if the female stands still and allows him to mount her for at least a minute or two.

Once the elephant is pregnant, she can remain so for almost 22 months – that’s nearly two years’ of pregnancy. However, due to the burden of pregnancy and child-rearing, elephants typically wait two to four years between pregnancies.

The calf she gives birth to – elephants rarely give birth to twins – can weigh nearly 120kg. At birth, calves are typically defenceless and do not exhibit the degree of survival, intelligence, or independence that one could expect from other, wild infants.

The calves drink milk for the first two years and are almost wholly dependent on their herd for the first few months of life – much like human infants. However, also like humans, the calves are quick learners and learn new skills by observing their elders.

The desert elephants found in Namibia share a special reproductive burden. They only tend to give birth every seven or eight years, and even then, the calf mortality rate is incredibly high. This is often attributed to the immense scarcity of resources, water, food, or shelter in the desert.