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Geophagy: why do animals eat soil?

The photo above captures one of Tsavo’s big tuskers using its impressive tusks to scrape at the ground. The loosened soil is then consumed by the elephant, as it contains essential minerals that the elephant requires to supplement its diet.

This behavior is known as geophagy, a widespread practice in the animal kingdom involving the intentional consumption of soil-like substances such as chalk, clay, or termite mounds. It allows animals to obtain minerals otherwise unavailable in their usual diet.

Geophagy in elephants

Elephants of all species engage in some form of geophagy to acquire essential minerals. Whether it’s sucking excess dirt off their trunks or actively digging and consuming soil from specific geological formations, these large mammals rely on the minerals from the soil as much as they depend on vegetation.

A study conducted on forest elephants in the Dzanga National Park of the Central African Republic uncovered that the elephants’ ongoing geophagy has resulted in the creation of large treeless areas referred to as “licks.” These licks are exclusively found in regions with dolerite intrusions, which are igneous rocks formed from cooling magma.

Chemical analyses of these areas revealed significantly higher quantities of vital minerals, including sodium, potassium, calcium, magnesium, phosphorus, manganese, and clay, in comparison to other soils. The knowledge of these locations is passed down through the generations and each lick is visited by several elephant herds.

Termites and tuskers

In the Ugalla Game Reserve in Tanzania, African savanna elephants have adopted a different approach to acquire essential mineral supplements. They consume soil from specific termite mounds. These mounds were found to be richer in mineral elements compared to other soil samples.

The reasoning behind this is that as termite colonies excavate their tunnels, they bring mineral-rich soil to the surface, providing valuable mineral supplementation to elephants and other animals.

The intricate relationship between one of the world’s largest creatures and some of the smallest, such as termites, highlights the significance of interspecies interactions. It shows that conservation efforts can constantly be enhanced by a better understanding of how the animals live. In this case, protecting termites in particular areas, by stopping the construction of airstrips, can be vital to the conservation of a whole elephant population.

Ecosystem engineers

Geophagy can also have an impact on the landscape and the environment. As elephants use their tusks to break up the topsoil they create depressions that collect water during rains, forming natural watering holes for other species. African elephants, renowned as significant ecosystem engineers, play a pivotal role in shaping the environment for various other animals.

The importance of soil for elephants extends beyond geophagy; they also apply it to their skin to protect themselves from sunlight and insects. This behavior gives rise to the well-known “Red Elephants of Tsavo,” named after the high iron oxide concentrations in Tsavo’s soil.

Conservation implications

It is believed that the knowledge of vital mineral deposits is passed down through generations, with experienced matriarchs following established migratory routes that pass by crucial mineral-rich areas.

It is clear these deposits are important for the elephant’s health however the impacts of habitat loss on mineral-dependent animals remains uncertain. Yet, with an improved understanding of these ecosystem interactions, conservation efforts can focus on safeguarding important geological formations, benefiting not only elephants but a myriad of other wildlife. This includes the protection of geophagic termite mounds for savannah elephants and dolerite intrusions for forest elephants.

In conclusion, the fascinating practice of geophagy among elephants reveals not only their remarkable adaptation strategies but also their crucial role as ecosystem engineers. From the creation of large treeless areas known as “licks” by forest elephants to the resourceful consumption of mineral-rich termite mounds by savanna elephants, these majestic creatures exemplify the intricate web of interspecies interactions that shape our natural world.

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