Africa is the world’s most various continent for giant mammals resembling antelopes, zebras and elephants. The heaviest of those giant mammals high the scales at over one ton, and are known as megafauna. In reality, it’s the one continent that has not seen a mass extinction of those megafauna.
The continent’s megafauna neighborhood consists of the world’s largest terrestrial mammal, the African elephant. Grownup African bush elephants can weigh as a lot as 6 tons. Different giants throughout African continent embody hippopotamuses, rhinoceroses and giraffes.
So, it’s only in Africa that ecological interactions and dynamics could be studied as they’d have been earlier than the sudden and profound flourishing of Homo sapiens over the previous 12 000 years; earlier than then, megafauna would have dominated all terrestrial landscapes on all continents. A go to to Africa is, in different phrases, a go to to our planet’s previous.
In my newest guide, African Ark: Mammals, Panorama and the Ecology of a Continent, I inform the story of how Africa’s mammal fauna arose.
It’s not only a story of megafauna and different well-known giant mammals. I pay specific consideration to small mammals, resembling mice, bats and shrews. That’s partly as a result of I’ve been finding out these creatures for the previous three a long time.
These animals are additionally usually missed by each scientists and the general public. However with out them, and the methods during which they’ve interacted with one another and with their bigger cousins over tens of hundreds years, Africa wouldn’t have the richly assorted landscapes it does right this moment.
Africa’s mammals are a world treasure that should be protected. Nevertheless, the lives of native communities are inextricably linked with these mammals and the remaining pure landscapes that harbour their dwindling populations; conservation options would require these communities’ lively participation and blessing.
In some areas, nature-based tourism could also be a viable answer. Nevertheless, a lot of the remainder of the continent – the place no vacationers go – would require different, maybe novel, approaches. What we can not afford is the extinction of any of those lovely creatures or the continued loss and discount of the ecosystem companies that they freely present.
Early mammal historical past
The historical past of African mammals begins with an apparently unrelated group of creatures. They’re so dissimilar from one another right this moment that taxonomists didn’t work out their true relationships till about 20 years in the past. These are the elephants, manatees, elephant shrews, African golden moles, hyraxes and tenrecs. Collectively they make up the super-order Afrotheria.
Right this moment, this group accounts for under a small fraction of the mammal species on the continent. However that’s solely as a result of Africa – which fashioned a part of the prehistoric southern supercontinent of Gondwana – was colonised, in levels and over thousands and thousands of years, by ‘invaders’ from the northern supercontinent of Laurasia.
These colonists embody practically all of the mammals that we usually affiliate with Africa, together with rhinoceroses, zebras, antelopes, primates, bats and even rodents. In return, some Afrotherians, together with elephants, roamed out of Africa to colonise different lands additional north.
Different mammals, together with monkeys and caviomorph rodents (resembling guinea pigs and capybaras), used Africa as a stepping stone to colonise South America, as did lemurs to colonise Madagascar.
Formed by geography
The variables of bodily geography have labored hand in hand with the tectonic forces of prehistory.
Africa just isn’t a uniform panorama that enjoys the identical local weather and habitat all through. Some components, resembling Madagascar, aren’t even linked to the mainland however seem as offshore islands. Terrestrial mammals usually attain islands in two methods: they both raft throughout the intervening sea, or cross by foot in periods of drier climate or decrease sea ranges that join the islands to the mainland.
Within the continent’s inside, different formidable boundaries prohibit and decide mammal motion. Lengthy, deep, fast-flowing rivers, such because the Congo in central Africa, could be virtually as efficient a barrier as open oceans. Mountain ranges can type inland ‘islands’ which might be as ecologically remoted as their ocean equivalents.
By offering boundaries, geographical options restrict the motion of animals throughout the panorama, thereby affecting the composition of mammal communities in numerous components of the continent.
One other factor that’s essential to telling the story of Africa’s mammals is an understanding of how species and inhabitants teams are fashioned and fluctuate over time.
For instance, megafauna play vital roles in shaping the panorama and its plant communities. This in flip shapes many smaller animals’ habitats. Hippopotamuses within the Okavango Delta create and keep open water channels, which function important habitat for fishes. And, by defecating in water, hippos additionally introduce huge quantities of natural fertiliser into this aquatic ecosystem, serving to to counterpoint it.
Smaller animals, too, form landscapes.
Some species of rats and mice, resembling pouched mice within the genus Saccostomus, are granivores that feed on seeds, together with these of timber answerable for bush encroachment in savannas such because the sicklebush. Colleagues and I’ve proven experimentally that varied species of mice in Eswatini truly desire the seeds of this encroaching plant and therefore can help in controlling its unfold. However these rodents require good grass cowl for persistence, and therefore can’t present this ecological service in over-grazed, degraded landscapes.
The numbers of animals naturally fluctuate over time, usually reflecting fluctuations in meals provide led to by, for instance, droughts or floods. A key determinant of those inhabitants fluctuations can also be the inherent life historical past traits of a species: short-lived, quick reproducing species resembling rats and mice will, by definition, expertise better fluctuations of their numbers than long-lived, gradual reproducing species like elephants.
My guide concludes by human interactions with African mammals and the necessity to preserve these mammals, each for their very own sake and for ours. The ecosystem companies supplied by many mammals are essential to a wholesome setting for all species. People advanced in Africa and have interacted with different African mammals for thousands and thousands of years right here.
This isn’t true on different continents, the place people are – in geological timescales – a current addition. It could be that this lengthy relationship between people and different African mammals is the explanation why, regardless of the losses wrought by humankind, so many giant mammals persist on the continent: they’ve ‘learnt’ via pure choice how you can survive with us.
The guide was written together with wildlife journalist Mike Unwin and is revealed by Wits College Press.