African bush elephant - Loxodonta africana

[Ceratodromeus]

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Proboscidae
Family: Elephantidae
Genus: Loxodonta
Species: L.africana


Subspecies
There are currently 4 recognized subspecies of African bush elephant, based on minor morphological and genetic differences. However, not all authorities view this as a reliable form of classification; One is now extinct*.

• Southern African bush elephant L. a. africana
• East African(Masai) bush elephant - L. a. knochenhaueri
• West African (Plains)bush elephant - L. a. oxyotis
• *North African bush elephant - L. a. pharaohensis

Biology
The African bush elephant is the largest and heaviest land animal on earth, being up to 3.96 m (13.0 ft) tall at the shoulder and 10.4 tonnes (22,930 lb) in weight (a male shot in 1974, near Mucusso, southern Angola). On average, males are 3.2 metres (10.5 ft) tall at the shoulder and 6 tonnes (13,230 lb) in weight, while females are much smaller at 2.6 metres (8.5 ft) tall at the shoulder and 3 tonnes (6,610 lb) in weight. The most characteristic features of African elephants are their very large ears, which they use to radiate excess heat,[9] and their trunk, a nose and an extension of the upper lip with two opposing extensions, or "fingers" at the end of it (in contrast to the Asian elephant, which only has one). The trunk is used for communication and handling objects and food. African elephants also have bigger tusks, large modified incisors that grow throughout an elephant's life. They occur in both males and females and are used in fights and for marking, feeding, and digging.

Adult males usually live alone. Herds are made up of related females and their young, led by the eldest female, called the matriarch. Infrequently, an adult male goes with them, but those usually leave the herd when reaching adolescence to form bachelor herds with other elephants of the same age. Later, they lead a solitary life, approaching the female herds only during the mating season. Nevertheless, elephants do not get too far from their families and recognize them when re-encountered. Sometimes, several female herds can blend for a time, reaching even hundreds of individuals.



The matriarch decides the route and shows the other members of the herd all the water sources she knows, which the rest can memorize for the future. The relations among the members of the herd are very tight; when a female gives birth, the rest of the herd acknowledges it by touching her with their trunks. When an old elephant dies, the rest of the herd stays by the corpse for a while. The famous elephant graveyards are false, but these animals have recognized a carcass of their species when they found one during their trips, and even if it was a stranger, they formed around it, and sometimes they even touched its forehead with their trunks.



Mating happens when the female becomes receptive, an event that can occur anytime during the year. When she is ready, she starts emitting infrasounds to attract the males, sometimes from kilometers away. The adult males start arriving at the herd during the following days and begin fighting, causing some injuries and even broken tusks. The female shows her acceptance of the victor by rubbing her body against his. They mate, and then both go their own way. After 22 months of gestation (the longest among mammals), the female gives birth to a single 90-cm-high calf which weighs more than 100 kg. The baby feeds on the mother's milk until the age of five, but also eats solid food from as early as six months old. Just a few days after birth, the calf can follow the herd by foot.

Like all species of elephant, the male African bush elephant experiences musth, a period of extreme aggression accompanied with high testosterone levels. A bull in musth has been known to attack anything which disturbs him including his family members, humans, and other passive animals such as giraffes and rhinoceros.In one case a young male African bush elephant has been witnessed killing a rhinoceros during musth.



The adult African bush elephant generally has no natural predators due to its great size, but the calves (especially the newborns) are vulnerable to lion and crocodile attacks, and (rarely) to leopard and hyena attacks. Some prides of lions prey on both infants and juveniles, especially in the drought months. Lions in Chobe National Park in Botswana have been observed for some time taking both infants (23% of elephant kills) and juveniles. Predation, as well as drought, contribute significantly to infant mortality.

---

en.wikipedia.org/wiki/African_bush_elephant

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Some information and data on Ahmed, a famous bull elephant who was known for having exceptionally long tusks.

digitalcommons.wayne.edu/cgi/viewcontent.cgi?article=1176&context=elephant

If you look at table 4 (scroll down to page 25/28), you'll see data comparing his tusks to other exceptional elephant tusks.

Left tusk length: 9'4"
Right tusk length: 9'9"

Left tusk circumference: 18.4"
Right tusk circumference: 18.3"

Left tusk weight: 148 lbs.
Right tusk weight: 148 lbs.

Earlier I posted information on the Asian elephant profile (see here->), detailing the handicap principle surrounding exceptionally long elephant tusks and their probable functions. Essentially, long tusks are cumbersome and not as suited for male-male combat as shorter tusks, but they are an honest signal of male fitness, particularly immunocompetency. This information on the dimensions and mass of Ahmed's tusks really gives you a sense of this. Together, Ahmed's tusks weighed 134.263 kg. To put this into perspective, an elephant around his body mass (he weighed some 5 tonnes) would have a skull (cranium+mandible) weighing 176.7 kg. Ahmed would have been lugging around two tusks that combined would have been somewhere around three quarters the weight of his own skull!

Here's a picture of him a couple days before he died in 1974 because why not? His skeleton-> is now on display in the Nairobi National Museum, Kenya.


Image source->

EDIT: also I have a source claiming that more aggressive elephants have shorter and more broken tusks than their calmer counterparts. It makes sense; a less aggressive elephant that fights less is less susceptible to fracturing a tusk, and therefore can grow its tusks to exceptional lengths if it avoids combat. This might support the idea that oversized tusks aren't there to be better weapons (if anything shorter, more reasonably sized tusks are better weapons), but serve as a signal of fitness.

Aside from size, the most obvious difference between a young and full grown elephant is the presence of tusks. One tooth on each side of the elephant's upper jaw grows dramatically over the animal's lifetime, and eventually, these two teeth form the tusks. The tusks of a male elephant, or bull, grow longer and heavier over the course of its life, reaching over 10 feet long and over 200 pounds. Although female elephants' tusks also continue to develop, their growth is less pronounced. As a result, the tusks of a female elephant, or cow, tend to be more slender than those a male elephant the same age. An elephant uses its tusks for everything from fighting to digging to feeding to marking. Elephants have been known to use their tusks to push over trees, which they then feed on. When competing for mates, male elephants will use their tusks to duel against each other violently. More aggressive elephants tend to have shorter, broken tusks than their calmer counterparts. It is not uncommon, however, for an elephant to prefer using one tusk over another, and for the preferred tusk to be shorter than its companion.

www.pbs.org/edens/etosha/elephant.htm

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Some might recall a study I've posted on here that found that musth overrides body size, which overrides tusk presence in male-male agonistic encounters in Asian elephants. African elephant researchers have also found that musth and body size are important predictors in male dominance and reproductive success.

“I think the finding that musth overrides body size and size overrides tusk presence is reasonable,” said Julie Hollister Smith, who was not involved in the study but worked on reproductive behavior in African elephants for her PhD at Duke University. “I believe that the fundamental factor in male dominance is size, which is tied directly to age. A male typically grows in size – both height and weight – as he ages, which allows him to remain in musth for longer periods. My findings in the best-studied African elephant population to date, was that the oldest males have the highest reproductive success.”

news.mongabay.com/2013/10/the-mystery-of-the-disappearing-elephant-tusk/

Below are excerpts from the study in question. As in Asian elephants, older (and therefore larger) African bulls are higher up in the male dominance hierarchy, but musth allows males to override size advantages.

Our analyses indicate that two factors profoundly affected the paternity success of male elephants. First, male paternity success increased with age until late in life. Second, most calves were sired by males who were in musth at the time of calf conception. The first result supports the observation that age predicts a male's position in the male dominance hierarchy, and that older males are able to outcompete younger males for access to females (Poole, 1989b, Poole et al., In press). In contrast to age, which represents a dominance queue, musth appears to allow a male to ‘jump the queue’ of the age/size dominance hierarchy; musth males can outrank nonmusth males (Poole, 1989a, Poole et al., In press), and because musth occurs asynchronously, unlike a seasonal rutting period, adult males of all ages reproductively contribute to the population. Musth does not annul the hierarchy, however.

As in Asian elephants, when musth status is equal, the larger elephant wins.

Older musth males had a marked advantage over younger musth males (Fig. 3). The effect of musth was more dramatic for older males, in part, because older males in musth are dominant over younger males in musth as well as over all males not in musth. In contrast, younger musth males are lower ranking than older males in musth, even though they can outrank males not in musth. This situation ultimately reinforces the reproductive dominance of older males, so that reproductive success increases dramatically with age for musth males until late in life.

Hollister-Smith et al. (2007)->. If the hyperlink doesn't work, just search for the paper (title is "Age, musth and paternity success in wild male African elephants, Loxodonta africana") on Google Scholar; access to the full paper is available via it.

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Some notes on how elephant combat works.


“When 2 equal-size bulls meet, they take each other’s measure by coming together with heads raised until their trunk bases and/or tusks are firmly engaged (fig. 17.8). This is also the position during combat. Each tries to be taller, to press downward on the other’s trunk. Or, if contact is made on the underside of their raised trunks, they may grapple for a hold. Tusk length is important, but so are height and weight, for these determine who can push whom around. The elephant that holds his head higher, whether because he is bigger or more confident, usually wins.”

“They entwine trunks, then try to twist or push each other out of line (fig. 17.9), while using the tusks as levers to force the opponent’s head down or sideways. When they break apart, the first to turn may be prodded gently in the flank by the victor. In a serious fight, this is the time and manner in which fatal goring may occur.”

The Behavior Guide to African Mammals Including Hoofed Mammals, Carnivores, Primates (p. 265)->

I have previously read in literature regarding Asian elephants that the tusks seem to be deployed for goring only after the opponent is rendered vulnerable (Chelliah & Sukumar, 2013). The observations above seem to be consistent with this statement, and for African elephants as well.

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Some information skin thickness variation. I wanted to get an idea of where exactly skin is thickest on an elephant. The information I've gathered below is the best I could find, though unfortunately is not necessarily from published scientific literature. The last three sources are, respectively, designed by an animal keeper who has more than 20 years of experience (including with elephants), a South African national park website, and an elephant conservation website, so take these for what you will.

Elephant skin can be ≥2.5 cm thick (I think up to 3 cm thick) in some areas of the body. These can include the hip and the upper hindleg, but the skin on the forelimb is thinner.[1]

On the sides and back, thickness varies from 10-15 mm (1-1.5 cm) thick.[2]

On the trunk, the epidermis appears to be 1/8 to 3/16 of an inch thick (~0.32 to ~0.48 cm). This same source reports the body having an epidermis 1/50 of an inch thick and a dermis ~11/16 of an inch thick.[3] This is a total thickness of ~1.75 cm, which seems more or less consistent with the figure mentioned above. Also, the dermis at the limbs, particularly at the margin near the nails, is 3/8 to 9/16 of an inch (~0.95 to ~1.43 cm) thick.[3]

Skin on some other parts of the body, like around the mouth, anus, or around the ears (or even the abdomen, chest, and shoulders), is said to be far thinner, being described as "paper thin" at these regions.[4][5] At the moment I have yet to find published figures, but one elephant conservation website claims that the skin on the ears and around the mouth is as little as 1/10 of an inch thick.[6]

There is an image of an (Asian) elephant that has been partially skinned and, from what I can tell, was sadly killed by poachers. Because the image may be upsetting, I will not show it directly, but instead hyperlink it->. The variation in skin thickness is evident. The skin on the back gets thicker posteriorly and is thinner anteriorly. The skin on the sides behind the forelimbs is also considerably thinner than on the rump.

For comparison with their fellow "pachyderms", rhinos have skin that is 15 mm (belly) to 25 mm (back and flanks) thick, and hippo skin can be similar in thickness (ca. 15-20 mm thick along the flanks, back, and rump). Indeed, a 1,600 kg adult male white rhinoceros would be predicted to have skin 7 mm thick based on allometry. The fact that it is, in reality, much thicker, shows that rhinos have disproportionately thick skin for mammals. By contrast, the 10-15 mm thick skin on the sides and back of an elephant is not significantly different than expected of a 5-6 tonne animal. This suggests that, unlike rhinoceros and perhaps hippopotamus skin, elephant skin is not highly modified as an armor against each other's tusks (serious fighting is apparently extremely rare). Instead, the epidermis is relatively thick and has surface sculpturing that's designed to prevent water loss.[3]

References:

[1] Fowler, M., & Mikota, S. K. (Eds.). (2008). Biology, medicine, and surgery of elephants. John Wiley & Sons.
[2] Shadwick, R. E., Russell, A. P., & Lauff, R. F. (1992). The structure and mechanical design of rhinoceros dermal armour. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 337(1282), 419-428.
[3] Smith, F. (1890). Histology of the skin of the elephant. Journal of anatomy and physiology, 24(Pt 4), 493.
[4] en.upali.ch/skin/
[5] www.sanparks.org/parks/kruger/elephants/about/biology.php
[6] elephantconservation.org/elephants/just-for-kids/#:~:text=The%20skin%20can%20be%20as

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The honeycomb-like inner structure of an elephant's skull appears to have a function in sound amplification and low-frequency acoustic and seismic detection. This might even be a trait inherited from the common ancestor of proboscideans and sirenians.

The cartilaginous, fat-filled lacunae of the manatee jaw, aerated skull sinuses, and fatty deposits on the manatee skull are thought to play a role in coupling sound to the manatee’s ear (13, 23). The structure of the manatee skull, incorporating unique fat deposits, may function to conduct sounds (39). Fossil data (4, 24) and the morphology of the fetal African elephant ear (10) indicate that Sirenia have common ancestral traits with elephants. Immunological evidence (12) further suggests that elephants and sirenians have a common aquatic ancestor. All head bones of the African elephant’s skull are also aerated by sinuses (64), and except for the solid mandible, the cranium consists of inflated bones compartmentalized to form diploe (59). The fatty deposits and aerated skull sinuses in the elephant may facilitate low-frequency acoustic and seismic detection.

Keeping an “Ear” to the Ground: Seismic Communication in Elephants->

The majority of elephant sounds are laryngeal in origin, produced by air passing from their large lungs over the vocal chords or larynx, a structure reportedly 7.5 cm long, suspended on the hyoid apparatus (Sikes 1971). The elephant's vocal tract includes the extent of the trunk, the honeycomb nasal passages in the skull, and the length from the lips to the larynx and has been estimated to be 2.5 m (Soltis 2009).

The Amboseli Elephants: A Long-Term Perspective on a Long-Lived Mammal->

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Importance of old bulls: leaders and followers in collective movements of all-male groups in African savannah elephants (Loxodonta africana)

In long-lived social species, older individuals can provide fitness benefits to their groupmates through the imparting of ecological knowledge. Research in this area has largely focused on females in matrilineal societies where, for example, older female African savannah elephants (Loxodonta africana) are most effective at making decisions crucial to herd survival, and old post-reproductive female resident killer whales (Orcinus orca) lead collective movements in hunting grounds. In contrast, little is known about the role of older males as leaders in long-lived social species. By analysing leadership patterns of all-male African savannah elephant traveling groups along elephant pathways in Makgadikgadi Pans National Park, Botswana, we found that the oldest males were more likely to lead collective movements. Our results challenge the assumption that older male elephants are redundant in the population and raise concerns over the biased removal of old bulls that currently occurs in both legal trophy hunting and illegal poaching. Selective harvesting of older males could have detrimental effects on the wider elephant society through loss of leaders crucial to younger male navigation in unknown, risky environments.

www.nature.com/articles/s41598-020-70682-y

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Ivory poaching and the rapid evolution of tusklessness in African elephants

Understanding the evolutionary consequences of wildlife exploitation is increasingly important as harvesting becomes more efficient. We examined the impacts of ivory poaching during the Mozambican Civil War (1977 to 1992) on the evolution of African savanna elephants (Loxodonta africana) in Gorongosa National Park. Poaching resulted in strong selection that favored tusklessness amid a rapid population decline. Survey data revealed tusk-inheritance patterns consistent with an X chromosome–linked dominant, male-lethal trait. Whole-genome scans implicated two candidate genes with known roles in mammalian tooth development (AMELX and MEP1a), including the formation of enamel, dentin, cementum, and the periodontium. One of these loci (AMELX) is associated with an X-linked dominant, male-lethal syndrome in humans that diminishes the growth of maxillary lateral incisors (homologous to elephant tusks). This study provides evidence for rapid, poaching-mediated selection for the loss of a prominent anatomical trait in a keystone species.

www.science.org/doi/10.1126/science.abe7389

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The low incidence of tusklessness shows that, for both sexes, tusks must be an important tool both for use in foraging and as weapons; but the fact that tuskless animals survive shows that they are not essential for the survival of the individual. Size is clearly less important for females than for males and their tusks are probably used for foraging rather than as weapons. The cessation of growth in females’ tusks at about 40 years old suggests that there may be other priority uses for dietary calcium and other elements for older female elephants. For example, to reduce the heavy demands on the female during pregnancy and lactation, these resources may be better invested in their offspring.

In males, however, tusk size must be more important. It is difficult to imagine that very large tusks would be more useful as weapons or tools than smaller ones, but it may be that larger tusks are of symbolic value in dominance skirmishes or displays. Males with larger tusks might be expected to occupy higher positions in the hierarchical structure or to be favoured as mates by females. However work in Amboseli National Park, Kenya (Moss, 1983; Poole, 1989a) suggests that the phenomenon of ‘musth’ is far more important than body size in determining a male’s hierarchical position and its success in mating. The condition of musth is easily recognisable to other elephants and the position in the social hierarchy of a male in musth is immediately elevated above all non-musth males. Even when two large males are simultaneously in musth, Poole (1989b) found that the factor determining dominance rank in both musth and non-musth males was body size. Tusk size is not mentioned by Moss (1983) or Poole (1989b) as a factor affecting hierarchical position. The evolutionary reason why some elephant males have large tusks is therefore still unclear, and would be an interesting subject for further research.

Source: Whyte, I., & Hall-Martin, A. (2018). Growth characteristics of tusks of elephants in Kruger National Park. Pachyderm, 59, 31-40. Retrieved from pachydermjournal.org/index.php/pachyderm/article/view/78

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Extremely rare cases of elephants with four tusks.

Image source->



Image source->

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The occurrence of elephant tracks at both Roberts Rock and Megafauna Rock is not surprising. Roberts' initial description1 of Roberts Rock placed it at the western edge of a 300 m, laterally persistent, low-angled, laminated facies containing numerous elephant tracks; bioturbation was noted, with tracks evident in successive bedding planes over a vertical extent of 4 m.

The slightly oval pes and more rounded manus tracks are distinctive, and there is no plausible trackmaker other than the African elephant (Loxodonta africana). There is no fossil evidence to suggest that earlier elephant species such as Loxodonta atlantica survived later than 400 ka. We have now identified fossil elephant tracks at many sites along the Cape south coast, including Dana Bay, Goukamma (six sites) and Brenton-on-Sea. One cross-sectional Goukamma site exhibits tracks in a section up to 26 m in thickness. While the elephant tracks at Roberts Rock and Megafauna Rock represent some of the southernmost evidence of elephants in the world1, submarine studies may expand the range further south onto the Palaeo-Agulhas Plain.

www.scielo.org.za/scielo.php?pid=S0038-23532019000100011&script=sci_arttext&tlng=es

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Tusk fractures are common in combat (Haynes, 1988). Seems to corroborate the limitations of elephant tusks as weapons, particularly in their strength. The fact that elephant tusks continually grow and can be worn back to a tip appears to make up for it, though.

[Supercommunist]

Aug 28, 2020 10:54:34 GMT 5 Infinity Blade said:

Some information skin thickness variation. I wanted to get an idea of where exactly skin is thickest on an elephant. The information I've gathered below is the best I could find, though unfortunately is not necessarily from published scientific literature. The last three sources are, respectively, designed by an animal keeper who has more than 20 years of experience (including with elephants), a South African national park website, and an elephant conservation website, so take these for what you will.

Elephant skin can be ≥2.5 cm thick (I think up to 3 cm thick) in some areas of the body. These can include the hip and the upper hindleg, but the skin on the forelimb is thinner.[1]

On the sides and back, thickness varies from 10-15 mm (1-1.5 cm) thick.[2]

On the trunk, the epidermis appears to be 1/8 to 3/16 of an inch thick (~0.32 to ~0.48 cm). This same source reports the body having an epidermis 1/50 of an inch thick and a dermis ~11/16 of an inch thick.[3] This is a total thickness of ~1.75 cm, which seems more or less consistent with the figure mentioned above. Also, the dermis at the limbs, particularly at the margin near the nails, is 3/8 to 9/16 of an inch (~0.95 to ~1.43 cm) thick.[3]

Skin on some other parts of the body, like around the mouth, anus, or around the ears (or even the abdomen, chest, and shoulders), is said to be far thinner, being described as "paper thin" at these regions.[4][5] At the moment I have yet to find published figures, but one elephant conservation website claims that the skin on the ears and around the mouth is as little as 1/10 of an inch thick.[6]

There is an image of an (Asian) elephant that has been partially skinned and, from what I can tell, was sadly killed by poachers. Because the image may be upsetting, I will not show it directly, but instead hyperlink it->. The variation in skin thickness is evident. The skin on the back gets thicker posteriorly and is thinner anteriorly. The skin on the sides behind the forelimbs is also considerably thinner than on the rump.

For comparison with their fellow "pachyderms", rhinos have skin that is 15 mm (belly) to 25 mm (back and flanks) thick, and hippo skin can be similar in thickness (ca. 15-20 mm thick along the flanks, back, and rump). Indeed, a 1,600 kg adult male white rhinoceros would be predicted to have skin 7 mm thick based on allometry. The fact that it is, in reality, much thicker, shows that rhinos have disproportionately thick skin for mammals. By contrast, the 10-15 mm thick skin on the sides and back of an elephant is not significantly different than expected of a 5-6 tonne animal. This suggests that, unlike rhinoceros and perhaps hippopotamus skin, elephant skin is not highly modified as an armor against each other's tusks (serious fighting is apparently extremely rare). Instead, the epidermis is relatively thick and has surface sculpturing that's designed to prevent water loss.[3]

References:

[1] Fowler, M., & Mikota, S. K. (Eds.). (2008). Biology, medicine, and surgery of elephants. John Wiley & Sons.
[2] Shadwick, R. E., Russell, A. P., & Lauff, R. F. (1992). The structure and mechanical design of rhinoceros dermal armour. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 337(1282), 419-428.
[3] Smith, F. (1890). Histology of the skin of the elephant. Journal of anatomy and physiology, 24(Pt 4), 493.
[4] en.upali.ch/skin/
[5] www.sanparks.org/parks/kruger/elephants/about/biology.php
[6] elephantconservation.org/elephants/just-for-kids/#:~:text=The%20skin%20can%20be%20as

Rhinoceros skin thickness visualized.



https://www.reddit.com/r/pics/comments/1425vp/this_is_how_thick_a_rhinos_skin_is/

Hippo skin thickness visualized.

x.com/Sophiesaurus98/status/1431899927257485317

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African elephants address one another with individually specific name-like calls

Personal names are a universal feature of human language, yet few analogues exist in other species. While dolphins and parrots address conspecifics by imitating the calls of the addressee, human names are not imitations of the sounds typically made by the named individual. Labelling objects or individuals without relying on imitation of the sounds made by the referent radically expands the expressive power of language. Thus, if non-imitative name analogues were found in other species, this could have important implications for our understanding of language evolution. Here we present evidence that wild African elephants address one another with individually specific calls, probably without relying on imitation of the receiver. We used machine learning to demonstrate that the receiver of a call could be predicted from the call’s acoustic structure, regardless of how similar the call was to the receiver’s vocalizations. Moreover, elephants differentially responded to playbacks of calls originally addressed to them relative to calls addressed to a different individual. Our findings offer evidence for individual addressing of conspecifics in elephants. They further suggest that, unlike other non-human animals, elephants probably do not rely on imitation of the receiver’s calls to address one another.

www.nature.com/articles/s41559-024-02420-w