Thegrasslands of Botswana in south-central Africa and of Colorado in the centralUnited States exist on opposite sides of the globe, yet they are eerily similarin appearance and function; a testament to the forces of evolution. When facedwith similar environmental conditions like soil type and levels ofprecipitation, and similar ecology like the patterns of how and whenprecipitation falls, natural selection opts for plants and animals that tendtowards similarity in their behaviors and sometimes even appearance. Can youtell which of the following images is from Botswana and which from Colorado?
The firstphoto is of the African savanna and the second is ofthe Colorado steppe. The grasses and plant associations are very similar. Andbelow are close up images of fruiting grasses, with the African savannaon the left and Colorado steppe on the right.
Theprairies of central North America are classified as temperate grassland, whilethose of Africa are tropical savanna. What makes grassland temperate? First,rain falls in spring and early summer, and is limited usually to about 20inches per year. This lack of rainfall coupled with the relatively thin soilsfound in temperate grassland prevents trees or shrubs from establishing.Second, temperate grassland experiences tremendous seasonal variations intemperature; temperate grasslands have a winter that limits the growing season.
Savanna grassland is the tropical version of the temperate grassland and in contrast totemperate grasslands they usually receive more rainfall and have some trees andshrubs scattered in the landscape. Savannas don’t experience a winter and arecaused by a distinctive climate pattern that includes a wet season followed bya long dry season without rain. Fires frequent the dry season and thin thetrees and shrubs that would otherwise invade the grassland. In both, it is therains that bring another cycle of life to the grassland. In North America it isan awakening that follows a long cold winter, in Africa it's the bloodthat breaths life back into the parched, dry and fire prone savanna.
Thelarge animals inhabiting the plains of both continents, either did, or stillundergo extensive migrations as they follow along behind the rains, engorgingthemselves on the grasses that respond almost immediately to the suddenabundance of moisture. In North America, it was bison, elk, and pronghorn thatoccupied the landscape in the 10,000s or even millions in the case of bison,moving like a silent army, tracking the rainfall across the landscape. InAfrica, it is the wildebeest, impala, buffalo, and other antelope that stillremain today, following the rains across the landscape and giving birth to anew generation of offspring as they move.
Bison on the North American plains, left, and buffalo on the African savanna, right.
Alongwith the large herds of roaming animals there exists robust populations ofpredators feeding off this cornucopia of wildlife. In Africa there are the wilddog, jackal, lion, leopard, cheetah, caracal, hyena, and honey badger. In NorthAmerica there are or were the wolf, coyote, fox, cougar, bobcat, grizzly bear, andbadger. It is striking how similar these predators are, there are canids, cats,badgers, and miscellaneous other predators in each grassland type. Can you tellme what is in the picture below? Is it from Africa or North America?
 | | No this isn't a coyote, it's a jackal on the African savanna |
As an ecologist, I find all of thisfascinating, something that is almost visceral and meaningful at a very deeplevel. I would encourage all of you who are reading this to contact us andstart planning your trip to Africa today to witness these majestic predators and the magnificentmigrations for yourself. Migrations that persist today as they have for eons ina landscape capable of making one think they were in a far off time,experiencing something long sense lost to our modern way of life.
Contact us and book your trip to Africa today!
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Elephants enjoy a good mud bath to cool off and to add a protective layer of mud on their skin. Here's a short clip of some elephants in Chobe National Park wallowing in the mud. As you'll see, sometimes it's easier getting in the bath than out.
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