Wednesday, January 9, 2008
THE MIGRATION IS ON...
If the natural world excites you then take a moment to pull out a map. Find East Africa; find Tanzania; find Serengeti National Park. Now point to the central plains and be impressed that right there at this very moment approximately 1½ million wildebeest accompanied by 250,000 zebra are passing through the area. Our planet’s greatest animal migration is on.
A couple weeks ago, in the Seronera Valley, we saw an endless line of determined wildebeest trotting south. Wildebeest make a deep nasally “hhhuuummm” call. Sort of like an oversized bullfrog. Amplify that 1,000 times over, throw in the incessant thumping of hooves on hardpan, and imagine a cloud of dust flying in all directions. Only then can you begin to appreciate this incredible event.
Observing the migration makes two things obvious: 1) wildebeest are by far the most numerous large animal in the Serengeti; and 2) an individual wildebeest is unspectacular. Looking at a wildebeest begs the question, “how can something so ungainly be so abundant?” After all, wildebeest do not have the speed of gazelle, the size or intelligence of elephants, the aggressiveness of Cape buffalo, the athleticism of impala, or the power of zebra. So, why are they so successful?
The answer, in part, has to do with their reproductive behavior. Right now, nearly every adult female is pregnant. Most will give birth during a three-week window in February when an average of 8,000 calves will be born everyday. Sure, marauding lions, hyenas, cheetahs, hunting dogs, and leopards take a few thousand but that leaves many more thousands unharmed. They simply overwhelm the predator population! Throw in the fact that newborn calves stand within four minutes and can run with the herd within a day and we can begin to understand why wildebeest are so successful.
A calf’s biggest danger is being separated from its mother as the heaving masses move towards greener grass. Because no calf will receive milk from another mother, separation spells certain doom. Calves, for their part, do not like to be alone. Their instinct to follow something is so strong that one lonely calf ran along side our safari vehicle as we drove by. On a couple of occasions I’ve seen lions feeding on a female wildebeest lying next to her dead calf. Presumably, the mother was ambushed, and with no other options, the calf hung around until it met the same fate.
Hundreds of thousands of wildebeest consume about 4000 tons of grass each day so they are in constant motion – always searching for new grass. This creates problems when the rains quite in June. The soils dry, the grasses brown, and the herds need to move north into Kenya’s Masai Mara. Along the way, they are forced to cross the Grumeti River where 16-foot crocs patiently wait for their annual feeding.
However, those are troubled times. It is raining now and there are endless fields of green nutritious grass. Adults and juveniles alike are sometimes seen “dancing.” They spin in circles, jump foolishly into the air, and kick their legs up high in what appears to be a “celebration dance.” It is this behavior that earned them the nickname “clowns of the Serengeti.”
This year, I was able to observe a part of the world’s most incredible animal migration. Observing this has shown me that wildebeest overcome horrific challenges and enjoy many successes. Because of this, I have developed a deep appreciation for them. But more profoundly, I take comfort in knowing that their 2,000-mile trek takes them across well-preserved and healthy ecosystems. I take comfort in knowing that this year wildebeest are doing what they have done for millions of years and today, like then, their fate is largely their own. Their annual “dance” ought to be celebrated by all who appreciate nature.