Elephants are very dextrous when stripping bark and branches from trees, using trunk, tusks and their feet in the process – as shown in this series of photos and video.

An elephant munching on bark from a small mopane tree, Kruger National Park

Stripping bark from a small mopane tree is not in the same class as stripping a large baobab tree but it is fascinating to watch how the elephant goes about it. Rather surprisingly, African elephants (Loxodonta Africana) are primarily grazers in the rainy reason, consuming huge amounts of grass and herbs relative to browsing on leaves and shrubs. In the dry season the grasses die back and elephants being obligate drinkers are confined to proximity to perennial water sources such as rivers that are associated with riverine forests. It is during the dry season that elephants turn their attention to foraging from suitable species of trees, consuming leaves, twigs, roots and bark, and of course fruit and flowers when they are available.

A cracking sound attracted our attention to this elephant as she used her tusks to bear down on a branch of a small mopane tree, bending her knees to provide more leverage

She then used her tusks and trunk to bend the branch upwards splintering it in the process

As the branch splinters some of the bark starts detaching and becomes easier to strip off

Elephants are able to meet many of their nutritional needs from foraging from trees, including the bark. Many vitamins and minerals are available to foraging elephants from these sources. Bark is more nutritious when the sap is rising in the inner bark that is more nourishing than the outer bark. Twigs and ends of branches are desirable fodder for elephants as the ratio of inner to outer bark is higher. Many studies show that higher consumption of bark by elephants is seasonal when grasses and herbs are not available.

The elephant is using a tusk and her trunk to tear off strips of bark

Elephants are highly selective of which species and even of which individual trees they forage from and studies show that their selection is based on the nutritional value of a specific species or a specific tree, which the elephant determines by sampling parts of the tree. The nutritional value even within the same species of trees depends on several factors. Soil type and its acidity/alkalinity has an effect on the bioavailability of nutrients to plants and thus to animals consuming parts of those plants. The age of the tree, fire, the season and climate factors also play a role in the nutritional value of trees. In some regions or seasons where trees lack certain essential minerals and other nutrients, elephants may be nutritionally stressed and that will affect foraging behaviour.

Due to human activity, protected wild animals, including elephants are increasingly forced into restricted areas – often fenced, which limits or prevents migration – where animals may not be able to meet their resource and nutritional needs.

It is easy to see how some elephants eventually wear grooves in their tusks where tusks are used as tools in bark stripping

Where elephants are not able to derive their nutritional needs such as essential minerals from plants and water sources, they create salt and mineral licks by using their tusks to excavate pits in soil and rock so they are able to access these resources from the soil. In confined areas they may not be able to realise these needs and nutritional stress can be especially pronounced during the dry seasons.

While feeding on long strips of mopane bark the elephant paused to look at us watching her from our vehicle. A strip of bark is draped over her trunk that she uses to place the bark into her mouth

The nutritional needs of elephants vary, with pregnant and lactating females requiring higher levels of nutrition and minerals such a calcium, than males and non-breeding females. Elephants therefore vary their foraging behaviours according to their nutritional requirements.

The elephant lifted her head providing us with a clearer view of her before resuming her foraging

After some time eating strips of bark she stepped forward to pick up a branch she had previously broken off and dropped to the ground 

She reoriented the branch before placing it back on the ground

She then deliberately placed a front foot on the end so as to hold the branch firmly in place to enable her to strip twigs off the branch to eat

And here she is stripping twigs from the branch while holding it in place with her foot

The type of browsing this and other elephants were doing in this mopane woodland has the long-term effect of coppicing or hedging the trees making leaf growth more accessible at the preferred height for foraging. It has been hypothesised that this is a type of deliberate ‘farming’.

However this hypothesis has been questioned, because although behaviour by individuals may result in benefitting the group in subsequent seasons this long-term benefit for the group is unlikely to be a driver of individual behaviour. Further, not all species of trees re-sprout successfully as mopane do and trees of some species die as a result of having their bark stripped or stems broken off (Midgley, Balfour & Kerley; 2005).

Some individual elephants indulge in snapping and toppling trees that is unrelated to them actually eating much of the tree. In some cases bark stripping too can seem excessive. Some elephants also push over structures such a telephone poles and sign posts. There is a hypothesis that such behaviour is a form of practicing for dominance contests between males or a form of confidence building, but behaviour from elephants that we see as being destructive is poorly understood and many questions remain unanswered (Midgley, Balfour & Kerley; 2005).

The elephant is able to strip off the top twigs while bracing the branch with her foot

It used to be thought that limiting tree damage from elephants required culling elephants to a predetermined ‘carrying capacity’ as used to be done in Kruger National Park for example. However, carrying capacity is now recognised as being dynamic rather than static in complex ecological systems and also tree destruction is not simply or directly related to the density of elephant populations as there are other factors at play. Culling is no longer used as a management strategy in the Kruger National Park. It did not produce desired outcomes and paradoxically, culling can lead to increase in birth rates as food can become more available in areas where culling has been carried out. Different management practices are required and research is ongoing.

Elephants do have the ability to change landscapes significantly and open up or maintain grasslands and their dung fertilises the land. There is the possibility that the well-treed landscapes regarded as ideal (these days especially for tourism purposes) is based on a colonial perspective that developed after the wholesale extermination of thousands of elephants due to hunting and the crash of populations of herbivores (including those browsing on trees) after the rinderpest outbreak in the 19th century.

In the period after the widespread eradication of elephants and other herbivores, trees became increasingly dominant in the landscape, which came to be interpreted as ‘ideal’. In more recent times the numbers of herbivores, such as impala, have increased in conservation areas, and it is evident that they have a significant impact on tree populations by eating seedlings and saplings.

Although elephants are often viewed negatively in their relationship with trees, in fact they are effective seed disperses – some seeds only germinate after being processed through their digestive tract and seeds are planted far and wide in the elephant dung, and so in this way elephants are significant propagators of trees, but at the same time their effect on larger specimens of some species of trees is cause for concern.

Elephants can use their trunks with great dexterity and finesse

Elephants can be very delicate in their foraging habits when needs be

An interesting illustration of the fact that elephants are not solely responsible for declining numbers of trees in a particular tree species is that in Kruger National Park a 300-hectare area from which elephants were excluded was fenced off to breed roan antelope. It was found that marula trees in the fenced-off areas disappeared at the same rate as outside of the fenced-off areas, indicating that there are complex factors at play, which include elephants, fire and climate change (TeamAG; 2019)

This elephant does seem to be enjoying her food – it can’t be termed a meal as elephants have to spend most hours in the day feeding in order to derive sufficient nutrition

It is beyond my capacity and the capacity of this post to properly discuss the complex topic of the impact of elephants on trees in conservation areas. It is increasingly being recognised that elephant management strategies must take into account other factors effecting tree populations, which include fire, soil and elevation and the presence of other herbivores, and also recognise that elephant behaviour and foraging patterns change from season to season and year to year often influenced by climate factors.

Management strategies that are being utilised in some conservation areas revolve around the provision of artificial watering points. Many artificial watering holes in the Kruger National Park have been closed, resulting in more migratory-type seasonal movement patterns of elephants and other animals that is beneficial to the restoration of vegetation and the preservation of trees. Reducing the number of artificial water holes in the park has already led to a reduction in the elephant population growth rate.

Some of the smaller conservation areas where elephants are very confined are utilising contraception in order to control elephant breeding levels. Sometimes translocating elephant groups may be possible although the scope for such removals is limited. Hunting trophy animals (older male elephants with large tusks) is not suitable as a management strategy in part because it skews the ratio of males to females and disrupts age structures.

In smaller reserves, targeted large trees can be protected by means of placing sharp rocks placed around them or installing African honey bee hives at such trees to deter elephants. It has also been found that wrapping the trunks of individual trees in protective fencing wire successfully prevents bark stripping by elephants.

The creation of trans-frontier parks also has the potential to restore elephant migration patterns but the alarmingly high levels of poaching of elephants across sub-Saharan Africa, which is increasing in southern Africa, means that the long-term future of free ranging African elephants is far from secure.

And to end, here is a short video taken by my spouse that better shows the elephant’s bark-stripping techniques than the stills do.

Sources:

Abraham, Joel O., Emily R. Goldberg, Judith Botha & A. Carla Staver. 2021. Heterogeneity in African savanna elephant distributions and their impacts on trees in Kruger National Park, South Africa. Ecology and Evolution, Vol. 11 (10): 5624-5634. https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.7465

Henley, M., & R. Cook. 2019. The management dilemma: Removing elephants to save large trees. Koedoe, vol. 61(1), 12 pages.  https://koedoe.co.za/index.php/koedoe/article/view/1564/2257#CIT0012_1564

Ihwagi, Festus Wanderi. 2007. Forage Quality and Bark Utilization by the African Elephant (Loxodonta africana) in Samburu and Buffalo Springs National Reserves, Kenya. Unpublished MSc dissertation, School of Biological Sciences, University of Nairobi.  https://www.researchgate.net/profile/Festus-Ihwagi/publication/238672736_Forage_Quality_and_Bark_Utilization_by_the_African_Elephant_Loxodonta_africana_in_Samburu_and_Buffalo_Springs_National_Reserves_Kenya/links/541950e20cf2218008bf674b/Forage-Quality-and-Bark-Utilization-by-the-African-Elephant-Loxodonta-africana-in-Samburu-and-Buffalo-Springs-National-Reserves-Kenya.pdf

Midgley, J.J., D. Balfour & G.I. Kerley. 2005. Commentary: Why do elephants damage savanna trees? South African Journal of Sciences 101: 213–215. https://open.uct.ac.za/bitstream/item/17514/%20Midgley_Article_2005.pdf?sequence=1#:~:text=Why%20do%20elephants%20damage%20savanna%20trees%3F,-J.J.%20Midgley&text=behaviour%20often%20appears%20to%20be,animals’%20preferred%20feeding%2Dheight.

Sach, Fiona et al. 2019.  “African savanna elephants (Loxodonta africana) as an example of a herbivore making movement choices based on nutritional needs.” PeerJ, vol. 7, e6260. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6361008/

TeamAG. 2019. Elephants and trees. Africa Geographic, October 9. https://africageographic.com/stories/elephants-and-trees/

Posted by Carol