|
Breeding
the Leopard Tortoise, Geochelone pardalis in
Captivity
Andy C.
Highfield and Jill Martin
Geochelone pardalis, the leopard
tortoise, is the second largest tortoise in Africa,
with some populations averaging 500 mm or more
carapace length with weights of 15-20 kg although
other populations, notably that of the Serengeti, are
considerably smaller (the largest tortoise in Africa
is Geochelone sulcata, the African Spurred
tortoise). Leopard tortoises are probably the most
manageable of the medium-large tortoises to maintain
in captivity, and in recent years have become very
popular indeed with tortoise enthusiasts.
Unfortunately, much of this demand has been met by the
importation of wild-caught and ‘ranched’ animals,
rather than by animals that are genuinely
captive-bred. Recent European import restrictions
mean, however, that future demand will have to be
accommodated by captive bred stock – therefore, it is
very important that additional effort is made to
refine captive breeding techniques for this species.
Leopard tortoises have a reputation of not being
particularly easy to breed in captivity. There are a
number of reasons for this. The most common cause of
failure, in our experience, is size incompatibility
between the male and female. Male leopard tortoises
almost invariably select the largest female available
to them – unfortunately, while they reason (correctly)
that she probably has the best reproductive potential,
this is not a lot of help if the size differential
means that they cannot even mate successfully with
her! Removing the largest animal, and leaving smaller,
more appropriately sized, females for the suitor to
choose from can make a substantial difference to
breeding success.
Leopard tortoises also need a good sized outdoor
pen, with plenty of mixed grasses for grazing, and,
in cooler climates, heated indoor areas where they
can sustain satisfactory body temperatures. Leopard
tortoises will not breed if maintained in cramped
conditions, or if kept too cold. One of the very
best housing methods for these tortoises in summer
in moderate climates is a large plastic agricultural
‘poly-tunnel’. Such a building allows good light
penetration, provides excellent all-round warmth,
and can be landscaped internally to provide cacti,
bushes for shade, and an easy-to-drain bathing pond.
Access to an uncovered outdoor area for grazing is
also essential. The poly-tunnel system allows for
relatively easy control of humidity – the tunnel is
typically very dry inside (quite suitable for
leopard tortoises, which do not tolerate damp at all
well), but if you do need to raise the humidity,
this is easily accomplished by installing an
agricultural mister or sprayer system. As such, the
basic poly-tunnel housing system is readily
adaptable to a range of environmental requirements,
from arid to tropical humid, suitable for Red-foot
and Hinge-back species, for example. Although not
suitable for over-winter use in northern climates
without additional heating, the Poly-tunnel housing
system is excellent for extending the space
available to many species throughout the spring,
summer and fall periods without running up heating
costs. To collect heat during the day, and radiate
it at night, some metal or plastic 50 gallon
barrels, painted matt black and filled with water
make excellent ‘storage heaters’. Such a tunnel,
planted with palms, yucca trees and cacti, can make
quite an impressive display and constitutes a very
pleasant environment for the tortoises.
The substrate for leopard tortoises in our own
units constitutes a standard sand-soil mixture. To
facilitate mating, it is best if this is contoured
somewhat, rather than flat. A few ‘hills’ and
mounds also assist basking. We have found this
substrate to be extremely successful and have had
no problems of any kind with it despite using it
for several years now. To enhance hygiene, the top
layer is scraped off from time to time and
replaced with fresh material. An adequate depth of
substrate is imperative – especially for females
about to nest. These are large tortoises, and nest
excavations reflect this. A depth of at least 300
mm (12") is required in nesting areas, even for
modestly sized females. Large specimens will
require around 450 mm (16"). Some females nest
quite late in the day. Indeed, one of our own
females habitually nests in the evening. There is
always a possibility (in the UK) that she may
become too cold as nesting progresses – we have
found that positioning a suspended 250 W basking
lamp over her until nesting is complete definitely
helps in this situation.
Leopard tortoises are prolific animals. Some
females produce clutches every 8-10 weeks, and
each clutch can contain from 6-20 eggs. These
eggs are large and spherical, averaging 40 mm in
diameter. Eggs are removed from the nest site
after the female has filled the excavation back
in with her hind legs, and are taken to our
normal tortoise incubators. We place the eggs on
a moist vermiculite substrate (the vermiculite
is hydrated 1:1 by weight with water), and they
are then incubated at 30-31° C. Incubation for leopard tortoise
eggs can be a rather extended process –
cases have been reported of incubation
taking 6 months or more. We generally find
that hatching occurs in approximately 5
months, but this is subject to quite a
degree of variation, even within individual
clutches. As an example, one female laid
four eggs on the 31st August
1999, and these all hatched in mid-January
2000. On the 3 November 1999, she laid
another clutch of seven eggs. These hatched
from the 4th April to 18th
May 2000. The resulting hatchlings weighed
from 12 to 16 grams.
Leopard tortoises have a reputation as not
being especially easy to breed in captivity,
but we have found that, even in northern
Europe, provided certain conditions are met,
and the animals well matched, consistent
success can be achieved.
Recommended
Reading:
• Practical
Care of Leopard and Sulcata Tortoises
(1999) by A. C. Highfield (video with
book) Carapace Press
• A
Beginner’s Guide to Leopard and other
South African Tortoises (2000) by
Misty Corton (Carapace Press)
• The South
African Tortoise Book (1988) by R. C.
Boycott and O. Bourquin Southern Book
Publishers (out of print)
• The
Tortoise and Turtle Feeding Manual
(2000) by A. C. Highfield, Carapace
Press
• Practical
Encyclopedia of Keeping & Breeding
Tortoises and Freshwater Turtles
(1996) by A. C. Highfield, Carapace
Press
|