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How did elephants evolve trunks?

Tsavo is full of wonderful creatures that seemingly push the boundaries of anatomical weirdness. The giraffe, whose neck alone can grow to more than seven feet in length, giving it a gangly, almost awkward elegance. The rarer gerenuk, with its elongated limbs combined with a cartoonishly squished face, lends it a lanky beauty. However, in this writer’s opinion, the most weird and wonderful creature that roams the plains of Tsavo, and much of Africa, is the elephant.

Working alongside these amazing mammals, it is easy to forget how uniquely weird they are. Every part of their body is stretched to enormous proportions. Their ears alone can span six feet long and five feet across. Their trunk, a fusion of the top lip and nose, is composed of up to seven feet of immensely strong and tactile muscle. Jutting from their impressively sized heads are two huge, scythe-like tusks, which can grow so long they scrape the ground. Place all these impressive features on a five-ton hulking body and back it with fierce intelligence, and it is clear to see these animals are a marvel of creation.

Elephant Brains
Elephants are epic in their proportions.

So, for this article, we will attempt to explain the creation of the African elephant, going back into the history of how this creature evolved into the awe-inspiring animals that walk our Earth today, with a particular look at the elephant’s most useful tool, its trunk.

Early ancestors of elephants

Elephants are part of a group known as the proboscideans, thought to have evolved 60 million years ago in Africa. The first proboscideans, unlike their modern relatives, were not very large. One of the earliest species, Eritherium, only weighed an estimated 5 kilograms and did not sport the characteristic long nose of elephant species today.

Around 30 million years ago, the group rapidly began to diversify, spreading around the world. This led to a wide range of elephant species, from tiny elephants on the Mediterranean islands to mastodons in North America. In fact, scientists have identified 175 species of proboscideans, belonging to 42 genera and 10 families.

One notable member of the probosicdeans was the giant Palaeoloxodon namadicus. This prehistoric elephant stood 17 feet at the shoulder and weighed 24.3 tons, making it the largest land mammal ever.

In the modern world, however, there are only 2 members of Proboscidea, Loxodonta and Elephas. Although both emerged in Africa, Loxodonta remained, leading to the rise of African savannah elephants (Loxondonta africana) and African forest elephants (Loxodonta cyclotis). Elephas moved into Asia, leading to various subpopulations of Asian elephants.

How did the elephant get its trunk?

Although elephants possess many anatomical adaptations that give them an evolutionary advantage, the most significant of these is the fusion of their nose and top lip, forming the trunk. But how did this amazing feature arise?

Interestingly, scientists theorise that the trunk’s original purpose was used as a snorkel to help the elephant breathe underwater.

One of the modern elephant’s ancient ancestors was Moeritherium. A semi-aquatic mammal, resembling a modern hippo and sporting a long tactile nose, similar to that of a modern-day tapir. This animal is thought to be one of the first of the proboscideans to develop a trunk, albeit a smaller one than we see on elephants today.

Elephants are aquatic?

Interestingly, there is more evidence to suggest that elephants were once semi-aquatic. Firstly, genetic testing reveals the closest relatives to modern elephants are the aquatic dugongs and manatees found in fresh water ecosytems.

There are other anatomical features that hint at the elephants aquatic past. The testes of an elephant are located inside the body, just like other aquatic mammals. Additionally, they possess a unique sphincter-like muscle that closes the ear canal and stops water entering.

Although the elongation of the nose may have originally been used as a snorkel, over time it evolved into something much greater.

Colin Watts Ilmouo6lo1e Unsplash
Elephants are competent swimmers. Photo credit Collin Watts from Unsplash

As elephants ancestors moved away from the water, the trunk changed to suit the environment, stretching high into the canopy to reach vegetation out of reach for many, and also reaching down to graze grasses along the floor.

Possessing endless degrees of movement, amazing finesse, unbelievable smelling capacity, and even a useful tool in communication, the elephant’s trunk is a unique and incredible adaptation.

If you would like to read more about elephant trunks, follow this link to a previous article. 

Protecting our remaining Proboscidea

Proboscidea once roamed all corners of the Earth, numbering at 175 species. Now, the world only has three species left: the African forest elephant, African savannah elephant, and the Asian elephant. All are keystone species, vital for their respective habitats, and all are threatened.

Here at Tsavo Trust, we are charged with the protection and monitoring of perhaps the most important sub-population of savannah elephants, and the climax of 60 million years of evolution, big tuskers.

Big tusker
A big tusker roaming the plains of Tsavo.

Big tuskers have tusks that can weigh over 50 kg each, scraping the floor as they walk. There are only 25 remaining big tuskers in the world and many reside within the Tsavo Conservation Area.

Therefore, providing protection from poachers and fostering coexistence between communities and elephants is paramount to preserving this group of elephants that boggle the mind with their enormous anatomical proportions.

If you would like to support our efforts in keeping the weird and wonderful animals of Tsavo alive, including the Earth’s few remaining big tuskers, then follow this link.

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