Dave Taylor's African Safari: Scavengers and Decomposers - Moss, Bacteria, Other Insects, Porcupine, Wind, Rain and Herds

Scavengers and Decomposers
Moss, Bacteria, Other Insects, Porcupine, Wind, Rain and Herds
Page 11

A wildebeest skeleton lies white and bleached on the plains. It is a mute reminder of a lion’s successful hunt. Here, an animal died and was eaten. Here, its life forces were passed onto a half dozen other species. The lion pride fed and when they left, the hyenas came in. Unlike the lions, they could crunch the bones and eat even the teeth. With this kill, however, there was no need to do this, for there was plenty of fresh meat on the plains that day. The migration had arrived and hunting for both species was good.

A black-backed jackal was next to grab scraps of meat. Then a few vultures found the remains but there was little for them to eat.

Had this wildebeest lived to die of old age, it would sooner or later have been reduced to bones even without the help of vultures and lions. Insects are more than capable of doing this job too. It is not long after an animal dies that the first flies find the body. They lay thousands of eggs in it. The eggs hatch and the larvae begin to consume their host.

Safari ants come too. They do not lay eggs, but instead take small bites of meat and carry it away to their colonies. Bit by tiny bit the insects do their job.

Horn moths lay their eggs in the horns and their larvae actually eat the horn and thrive on it.

All of these, ant to lion, produce waste converting the dead wildebeest to gases and dung. All of these animals, too, end up as carcasses and have their own set of attendant recyclers.

Bacteria

Bacteria begin their job the instant death happens. Billions of these organisms live in and on all life. When the wildebeest, for example, was alive, certain types of bacteria lived in its rumen and made it possible to extract nutrients from the grass. As long as the wildebeest lived, its own systems coped with and nourished the bacteria.

When it died, they, along with other types of bacteria, were free to begin consuming their former host. If vultures or some other animal does not open the carcass, the bacteria will. One of their waste products is methane gas and after a day or so the carcass begins to swell and bloat. The skin stretches as if a balloon was being blown up inside it. Sooner or later, like a balloon, it will burst, opening the body cavity for others to feed on.

Bacteria do not limit their decomposing activities to animals. Every blade of grass and every dead tree also benefits from their activity. Bacteria and other organisms that feed on decaying matters are called detritiovres.

It is not animal and bacterial action alone that cleans up the carcass. Moss finds the smooth skull and bones a source of nutrients on which to grow. Most skeletons on the plain have a faint greenish look to them due to this colonizing plant’s presence.

The Greatest of Them All

The greatest decomposer is fungi. Tiny white filaments of fungi run through the soil seeking nourishment. Sometimes, a species of fungi benefits its neighbors. Fungi threads help tree and grass roots get needed nutrients while they receive needed nutrients in return. Other species have their nutrient needs met by helping to decay dead material; plant, animal or bacteria.

Still, a bone is a bone and one would think that they would last longer on these plains. In reality, the clean-up crew on the Serengeti-Mara is so good that finding a complete skeleton is relatively rare. Most of the time, the bones you see are skulls.

The bones disappear for a number of reasons. Certainly moss, fungi and insects help to get rid of them. So do the great herds. Bones are trampled and broken as the herds migrate across the plains. They are kicked, dislodged and moved about by countless hooves.

Others seek them out to gnaw on. The African porcupine will chew on a bone to get calcium. A warthog might chew one for the same reason. Mice and rats also use their chisel-like teeth to convert the bone to something they can swallow.

Weather also does its part. Winds blow tiny grains of sand at the bones and erode them. Raindrops pelt away at it, breaking it down. Heat bakes it and night breezes cool it.

Finally, when all have taken their share, the bone is gone. Dust to dust. Ashes to ashes.

The wildebeest is gone, recycled and reused. We have come full circle. We began with the abiotic and we end with the abiotic. This is the story of the Serengeti-Mara ecosystem.

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