Loxodonta
africana (African Elephant)
Superorder: Paenungulata
Order: Proboscidea
Family: Elephantidae
Genus: Loxodonta
Species: africana
Sub-species: africana
General Description/Adaptations:
No general
description is necessary for this animal.
Males and females
both have tusks, but can be distinguished by size, as well as forehead shape –
bulls have rounded forehead, cows have angular forehead. (Walker, p. 114)
Loxodonta refers to the enamel pattern
on the molars. They have six sets of
molars – as each set gets worn down, the next set pushes forward. When they are out of molars, they die. (Walker, p. 120)
Probably evolved
from the forest elephant, and then had a large increase in size due to the need
to eat lower-quality vegetation. Color can range from almost black to gray to
pink. The large, rounded ears are used
for hearing, communication, and cooling. (Kingdon, p. 303)
Tusks are
oversized incisors, and continue to grow throughout the life of the
animal. Males’ tusks are more developed
than female. Average tusk weight at 60 years is 61 kg for males and 9.2 kg for
females. Record weights are 106 kg and
25 kg, with a record length of 355 cm.
(Estes, p. 259)
Size: (Kingdon, p. 305)
Weight: Female 2,200 – 3,500 kg; Male 4,000 – 6,300
kg
Shoulder
height: 1.6 – 2.4 meters
Habitat:
They are
shade-dependent during the hot and dry season, which may be a result of their
relatively recent evolution out of the forest (10 – 20,000 years ago. Will they become less water and
shade-dependent over time?).
Elephants have a huge impact on their habitat, changing entire plant
communities, creating waterholes, creating paths through forests, ploughing
soil and excavating caves for salt. At
this time this subspecies is predominantly found in savannah parks with access
to year-round water. (Kingdon, p. 306)
They can live in
a wide variety of habitats, but prefer forest edges that provide both grass and
browse, shade and water. (Estes, p. 260)
Range/Parks:
Originally found
throughout most of Africa except the driest
parts of the Sahara. They can forage up to 80 km away from water,
so can use very marginal areas. They are
now limited to pockets and national parks. (Kingdon, p. 305)
Home Range:
Home range varies
by quality of habitat. Can be as small
as 14 sq. km. or as large as 3,500 sq. km. in dry areas. (Estes, p. 261)
Food/Water:
They eat a LOT (180 – 270 kg/day for an adult bull). 80% grasses, but also leaves, mlala palm,
bark, roots, wild fruit, acacia seed pods (they are unaffected by the
thorns). They move continuously while
feeding, and dig, and strip and gouge bark with their tusks as they travel, and
will also use their forelegs to dig for roots and digging water holes. They can go a number of days without water,
but will drink up to 100 liters at a time when they have access. (Walker, p. 119)
They eat up to 5%
of their body weight each day, and the vegetation takes about 12 hours to pass
through their system. (Kingdon, p. 306)
Focus on grasses
and herbs in the rainy season and woody browse during the dry season. Can be found in open savannah during wet
season and in forests or near water during dry season. Studies of their dung show that they process
only 44% of the food they eat, compared to 66% for ruminants. (Estes, p. 260)
They will poop
out about 155 kg of dung per day!
(Estes, p. 262)
Breeding:
Females begin
breeding after 8 years, and are in estrus for 2-6 days every 3 – 9 years. They communicate their availability by
sending out infrasound signals that can be heard by other elephants up to 4 km
away. All males in the area will come,
but musth bulls always win. They have higher levels of testosterone, and
are extremely aggressive. Musth will
last 1 – 103 days, and is indicated by a continual secretion of fluid from the
temporal glands and, sometimes, a semi-erect penis dribbling urine and a
greenish fluid. (Kingdon, p. 307)
Gestation lasts
about 22 months and generally only one young is born – rarely two. They are able to stand within a few hours,
but are unsteady on their feet for several weeks. Mothers are very attentive and protective,
and will even regurgitate water if they think their offspring is getting
dehydrated. Mothers will produce milk
for at least 4 years, although young can survive on solid food by 2 years. They remain dependent for up to 10 years.
(Kingdon, p. 307)
Social Organization:
Very complex
organization, involving dozens of clan members and potentially hundreds of
regular acquaintances. This is seen as
evidence of high intelligence and long memory. (Kingdon, p. 303)
Central unit is
mother and offspring. Females begin
producing young between 8 and 20 years old and soon after become
“matriarchs”. Groups tend to split once
there are ten daughters and grandparents, but continue to interact and stay in
the same areas. These extended
associations are referred to as “bond-groups” or “clans”. Males are driven off by 10 – 14 years, at
which point they may join bachelor groups.
(Kingdon, p. 307)
The matriarch
sets foraging direction and speed. When
she stops, they stop. When she moves on,
they move on. Members of the family unit
are rarely more than 50 meters from each other.
When disturbed, they all gather around the matriarch and wait for her
lead. They bunch together nervously when
crossing open areas, the matriarch taking the lead and another female bringing
up the rear. (Estes, p. 261)
The killing of a
matriarch leaves the rest of the group vulnerable due to their
disorientation. They will often let
themselves be shot rather than leave the side of the matriarch. They will try to lift her and help her get
away if she is wounded. (Estes, p. 261)
Young males will
leave the herd at adolescence, but may remain peripheral, following the
maternal herd, for a long time before becoming completely separate. Bachelor herds may be as large as 144, but
are more often 2 – 12. (Estes, p. 261)
Communication:
A charge may be preceded by a rocking motion,
and one foot swinging to and fro. The
head may also be shaken with a loud slapping of the ears. A charge is often accompanied by trumpeting. During an actual attack, the trunk will be
held between or to the side of the forelegs. (Walker, p. 116)
Elephants have recently been found to
communicate with low-frequency vibrations, below the level of human
hearing. They do this primarily in the
early morning and late evening when air pressure is most conducive to the sound
waves traveling. This “infrasound” was
discovered in 1987. (Kingdon, p. 307)
Greeting
Ceremony: Clan members greet each other very
warmly. The primary greeting is for the
subordinate member to insert its trunk in to the mouth of the dominant. They will signal greeting-intention by moving towards each other with their trunks
outstretched. (Estes, p. 262)
There is much physical contact between clan
members. Courting elephants will caress
each other and twine their trunks, playing ones might trunk-wrestle. (Estes, p.
263)
Vocal:
Rumbling: deep growling for long-distance communication. Much of this is below the range of human
hearing and can travel over several kilometers.
Quiet rumbles are also used while feeding to stay in contact with one
another. With increased excitement, the
rumble can become a bellow or a moan, becoming an intimidating roar when
threatening a potential predator.
Trumpeting: Sound
of excitement caused by forcing air through the nose. Short blast indicates that the animal was
startled. Drawn out may indicate rage. Is combined with growling and screaming in
threat displays. May also be used as an
alarm or call for help, or may be used during intense greeting.
Squealing:
Juvenile distress call. Elicits
an immediate response from mother and other females.
Screaming: Adult
equivalent of the squeal. Used to
intimidate opponents along with trumpeting.
Flapping of ears and raising of head is an alert posture. If these are not combined, though, the
flapping of ears could just be temperature regulation, and raising of head and
trunk may just be a way of testing the air.
Always look for combinations of behaviors to understand what is being
communicated. Head movement up and down or side to side often signals a threat
display. (Estes, p. 263)
Activity
Patterns:
They spend 16 –
18 hours per day feeding in order to consume (for males) between 180 and 270 kg
of fodder. (Walker,
p. 118)
Dry Season: Move into wet “refuge areas” and flood plains
where the grass is still growing. Once
all surface water is gone, they move to hills, forests and rivers. They feed less and rest more. This is the period when they do the most
de-barking of trees. (Kingdon, p. 306)
Wet Season: Males make the first move into the areas with
new, green growth. They start out
concentrated in these pastures, then disperse.
As the growth of grass increases, they increase the time spent feeding
and become more active. Towards the end
of the rainy season, when grass is long everywhere, they are widely dispersed
throughout grasslands and savannah. (Kingdon, p. 306)
They sleep 4 – 5
hours per day. (Estes, p. 262)
Lifespan:
50 – 65 years or more. (Kingdon, p. 303)
Sign:
Fresh dung is
olive to bright yellow. The size of the
piles is amazing at times (I saw one pile
that was almost a meter high). Walker suggests that to
test for freshness, you can push your hand to the center of the pile and see if
it is still warm. Hmmm. I prefer his color guidelines – it will be
dark for up to 5 or 6 hours, then will gradually get lighter. Stress can cause diarrhea. Changes in vegetation and seasons will also
affect consistency. During dry season,
there will be lower water content. (Walker,
p. 120)
Tracks
look like somebody set down a row of dinner plates and then picked them
up. Surprisingly narrow trail width for
such a large animal. The forefoot is
larger than the hind and is circular or oval, the hind is smaller and longer
rather than round. Forefoot has five
toes, hind foot has four. (Walker, p. 120)
When
tracking elephants, check for “scuff marks”.
The front foot is lifted, whereas the hind foot is scraped along the
ground. This can help determine
direction of travel. (Walker, p. 121)
The
pattern of cracks in the feet are individually distinct, so can be used for
identifying individuals. (Kingdon, p. 305)
Predators:
The only predator that can threaten an adult
elephant is the human. Calves can be
taken by lions or hyenas, but protective mothers make this difficult. (Kingdon,
p. 308)
Conservation/Commercial
value:
Elephants have
had a very difficult history in Africa. They have been exterminated from many parts
of Africa through a combination of ivory
poaching, increasing aridity in the Sahara
region, and elimination as crop pests.
Legal protection increased from 1920 – 1970, which helped, but then
political instability, especially in Uganda, brought them to the brink
of extinction. IN the 1930’s and 1940’s,
it was estimated that there were between 5 and 10 million elephants in Africa. By the
late 90’s, the population was estimated at between ½ and ¾ million. It has been listed as an endangered species,
and the numbers are once again rising. (Kingdon, p. 308)
Elephants destroy
a great number of trees. When their
populations are spread out, this is good as it leads to habitat diversity and
gives smaller browsers access to treetop food sources. Currently, however, elephant populations are
confined to national parks and are having too much impact. Their conversion of woodlands to grasslands
in Murcheson Falls has been detrimental both to
elephant and rhino populations. (Estes, p. 260)
Other Information:
Should always be
approached with caution. Poor eyesight
and hearing, cows are particularly nervous and will especially attack if they are with young. Bulls are more tolerant
and will more likely bluff-charge than actually attack. Bulls can usually be driven off by throwing
clods of dirt or wood onto the ground in front of them or by shouting and
clapping one’s hands. (Walker, p. 116)
References:
Estes, R. (1991).
The Behavior Guide to African Mammals. Berkeley, CA: The University of California
Press.
Kingdon, J.
(1997). The Kingdon Field Guide to
African Mammals. Princeton,
NJ: Princeton
University Press.
Walker, C.
(1996). Signs of the Wild: A Field Guide
to the Spoor & Signs of the Mammals of Southern Africa.
(5th Edition). Cape
Town, South Africa: Struik Publishers Ltd.
Photo by Mark Jordahl