Grasses make up
most of an elephant’s daily diet. This means that elephants travel
on most days to find clearings at the edge of forests where they
spend hours gathering grasses with their trunks. After ripping off
a bunch of stems, they typically swirl it in the air and pound it on
the ground before putting into their mouths. Presumably this rids
the plant material of unwanted dirt and debris.
Most elephants
repeatedly swirl and pound each bunch of grass before
eating it
photo M. Noonan
Like most
herbivores, elephants depend on beneficial bacteria that produce
necessary enzymes inside their digestive systems—enzymes that are
able to break down the cellulose in plant cells and convert it to a
source of energy for the elephants. In other words, when an
elephant eats grass it is really feeding the bacteria in its
digestive system, and these bacteria in turn feed the elephant.
Micrograph of elephant fecal matter showing numerous beneficial
bacteria
However, elephants
cannot maintain good health on grass alone. Like humans, they need
a minimal level of protein in their diet, and grasses are a poor
source of protein. This means that an elephant must also spend part
of each day in search of plants that are in their active growing
stages, plants that are producing new leaf buds and growing stems
that have high levels of protein. Additionally, they must find
plants that will provide them with a minimum level of other
necessary nutrients (calcium, magnesium and so on) that are
essential to their health.
Elephants move daily into, and out of, grasslands
photo M. Noonan
To satisfy all of
its needs, an adult elephant consumes about 300 pounds of plant
material per day, and it moves about 10 miles per day, seeking out
and eating small amounts of many different plant species.
Naturalists have counted 112 different plant species that elephants
consume at one time or the other throughout the year.
It is not
necessary to infer that elephants understand their
nutritional needs in any conscious way. It is just
that they have been built with a taste for certain plant
species, and that is enough to drive them to seek out
and gather in the appropriate foods.
Elephants live
very long lives and they appear to remember locations of
desirable plant species from year to year, and maybe
even from decade to decade. By leading the group from
place to place, matriarchs evidently pass this knowledge
down to their daughters and grand daughters.
