Geographic Range
Leopard tortoises (
Geochelone pardalis
) are endemic to Africa, and their geographic range extends from Sudan to Ethiopia
and from Natal in eastern Africa to southern Angola and South Africa. They are also
diffusely distributed throughout portion of southwestern Africa.
Habitat
Leopard tortoises occupy a variety of xeric and mesic habitats throughout their geographic
range, ranging from dry arid plains to temperate grassland ecosystems. They are intolerant
of damp or cold habitats. They have also been reported in mountainous terrain. These
tortoises spend most of their time in shrub habitat with low lying vegetation, which
serves as their primary food source. In the summer, they seek shelter under various
low lying plants.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- desert or dune
- savanna or grassland
- forest
- mountains
Physical Description
Leopard tortoises are the fourth largest tortoise species in the world. They exhibit
indeterminate growth and adults range in mass from 15 to 54 kg, with an average of
18 kg. Carapace length ranges from 30 to 70 cm, with an average carapace length of
45 cm. Females are often larger than males. It also is common for leopard tortoises
to have moderate carapacial pyramiding, a shell deformity in which scutes exhibit
pyramidal growth. Leopard tortoises differ from other members of the genus
Geochelone
due to their distinct shell markings. Base color of the carapace may be tan, yellow,
or sometimes shades of dusty brown. The intensity of shell patterning varies. Blotches
on the shell are most often black and are typically only present on juveniles. The
head, feet, and tail vary in color but are usually tan to brown. Despite differences
in appearance, the diet and habitat of tortoises in the genus
Geochelone
are usually similar.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
Development
Leopard tortoises are oviparous, and their eggs are initially leather-like but dry
to become hard and brittle. The egg contains a large, nutrient-rich yolk, which the
embryo feeds on during development. Sex determination is temperature dependent; females
develop under average temperatures of 30 C or more and males develop under average
temperatures of less than 30 C. Temperature-dependent sex determination suggests that
the mother has some control over the sex ratio of her offspring. If she lays her eggs
in a warm environment the sex ratio favors females, whereas a cool environment favors
males. Eggs are roughly spherical and about 57.5 mm in diameter. Clutch size ranges
from 7 to 20 eggs, and most eggs hatch within 47 to 180 days. After hatching, young
tortoises grow very rapidly during the first few months of life. In general, hatchlings
in this genus weigh around 100 grams and grow between 300 and 400 grams during their
first year of life.
- Development - Life Cycle
- temperature sex determination
Reproduction
Leopard tortoises are monogamous, and both males and females become increasingly aggressive
when searching for a mate. They fight for mates by butting and ramming rivals. During
courtship, males follow their potential mate and repeatedly run into them until the
females become immobilized. Males sometimes lift their mate off the ground by ramming
them. Females become defensive and in some cases try to escape. During copulation,
males mount the female and extend their necks and grunt during mating.
- Mating System
- monogamous
Leopard tortoises breed from May to October. Males become reproductively mature by
five years of age, and although the specific age of maturation is unknown, females
are thought to become reproductively mature later than males. After mating, females
dig a hole in the ground, ranging from 100 to 300 mm deep, in which to lay her eggs.
The frail eggs are white and spherical. Gestation ranges from 9 to 12 months and varies
according to location, temperature, and precipitation. Females lay 5 to 7 clutches
during a single breeding season, with each clutch separated from the previous by about
3 to 4 weeks. Clutches range from 5 to 30 eggs, with larger female having larger
clutches.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
Paternal care in leopard tortoises is non-existent, as males leave directly after
copulation. Females dig a hole in which to lay their eggs, which ranges in depth from
100 to 300 mm. After the eggs are laid, she covers them and leaves. Hatchlings are
immediately independent upon emerging.
- Parental Investment
- no parental involvement
Lifespan/Longevity
In the wild, adult leopard tortoises may live for up to 100 years. No records are
available regarding captive individuals. However, typical lifespan for other species
of
Geochelone
tortoises in captivity is approximately 50 years. Factors that may limit the lifespan
of leopard tortoises include human impacts through the pet trade and male aggression
during courtship and mating.
Behavior
Auditory perception is important to leopard tortoise mating behavior, as males vocalize
species-specific calls in an attempt to attract females. Males also vocalize during
competition for mates. Male vocalizations include a variety of grunts and groans.
Although tortoises do not audibly respond to vocalizations, most are visually responsive.
Like most other tortoises, leopard tortoises are known for their hissing noises. When
feeling threatened, tortoises quickly pull the head and feet into the shell, resulting
in air being forced from the lungs and thus the distinctive hissing noise is produced.
Males possess neck glands, which inform conspecifics of their willingness to mate
or battle another male. Evidence suggests that, during mating season, male tortoises
follow females for days or even weeks at a time before initiating courtship. In order
to initiate contact, males bite the female on the head or feet. Social hierarchies
are established via aggression, as dominance is established through a series of competitions.
Social networks among the tortoises are fairly weak, with little intraspecific communication
occurring.
Home Range
There is no information available regarding the average home range size of leopard
tortoises.
Communication and Perception
Communication and perception within leopard tortoises is primarily visual, however,
there is little evidence to suggest that tortoises are able to distinguish between
different colors. A recent study proposed juvenile leopard tortoises most often approach
colors such as red and different shades of green. In general, tortoises are particularly
sensitive to sounds under 1,000 Hz.
Food Habits
Leopard tortoises are primarily herbivorous, with plant material making up approximately
98% of their diet. They consume berries and other fruits when available. Bone fragments
and ash may be consumed during times of decreased resource abundance. Although most
tortoises
consume mostly grasses, leopard tortoises primarily consume forbs. They feed primarily
from the ground, particularly from areas within their habitat that produce low-lying
forbs.
- Plant Foods
- leaves
- seeds, grains, and nuts
- flowers
Predation
Leopard tortoises are well camouflaged and are difficult to capture given their thick,
heavy shells. Tortoises suffer the highest predation rates prior to hatching due to
predation on eggs. Nearly 80% of hatchlings may eaten by predators such as
foxes
,
coyotes
, and
mongooses
. Adult tortoises are preyed upon by
humans
and are usedful in creating medicine, tools, and are often used as a source of food.
Ecosystem Roles
Leopard tortoises are important seed predators and disperse seeds throughout their
environment. They commonly forage on plants that are close to the ground and ingest
a large number of seeds, which are redistributed throughout their geographic range
via defecation. They also consume the seeds of berries and other fruits, which are
redistributed after consumption as well. Leopard tortoises are vulnerable to
tortoise ticks
. There is no other information available regarding parasites of this species.
- Ecosystem Impact
- disperses seeds
- tortoise ticks ( Amblyomma marmoreum )
Economic Importance for Humans: Positive
Leopard tortoises are sometimes hunted for their meat and for the pet trade and are
used to create traditional medicine. As an indigenous food source, they are cooked
in their shells, however, this does not occur frequently and does not seem to significantly
affect population abundance. According to Schedule 2 of the Western Cape Nature Conservation
Laws Amendment Act of 2000, leopard tortoises are classified as "protected wildlife",
which restricts trade of whole animals, dead or alive, and by-products of this species.
- Positive Impacts
- pet trade
- food
- source of medicine or drug
Economic Importance for Humans: Negative
Geochelone pardalis
is regarded as an agricultural pest (pumpkins, beans, and cowpeas) throughout its
geographic range.
- Negative Impacts
- crop pest
Conservation Status
Although many species of
tortoise
are becoming increasingly threatened, leopard tortoises have not been evaluated by
the International Union for the Conservation of Nature (IUCN). They are endemic to
Africa and are currently listed under CITES' Appendix II. Although Tanzania has the
largest recorded leopard tortoise population, with an estimated 5,990 individuals,
it also has the highest mortality rate of any country containing leopard tortoises.
Ethiopia is second, with only 500 individuals. Leopard tortoises are regarded as agricultural
pests throughout their geographic range, and as a result, retaliatory killings are
not uncommon.
Additional Links
Contributors
Hillary H. Baker (author), Radford University, Jordan N. Grubb (author), Radford University, Christine Small (editor), Radford University, John Berini (editor), Animal Diversity Web Staff.
- Ethiopian
-
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- desert or dunes
-
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
- tropical savanna and grassland
-
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
- savanna
-
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
-
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- monogamous
-
Having one mate at a time.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- motile
-
having the capacity to move from one place to another.
- social
-
associates with others of its species; forms social groups.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- pet trade
-
the business of buying and selling animals for people to keep in their homes as pets.
- food
-
A substance that provides both nutrients and energy to a living thing.
- drug
-
a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
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