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Glasgow
Zoopark has an enviable reputation for captive-breeding Burmese
Brown tortoises.
The
female Burmese Brown tortoise chooses to lay her eggs in piles of
rotting grass, left by the keepers specially for this purpose in
the outside enclosure. We erected a small greenhouse in the enclosure,
making sure it was raised up about 60 cm above the ground to ensure
the glass was tortoise proof!Under the greenhouse we place a large
pile of coarse compost. The female tortoise carefully gathers the
compost together over a few days, constantly checking the temperature
by poking her head down into the compost at intervals. When she
finds the right conditions, she lays a clutch of about 40 eggs.
After a surprisingly short incubation period of only 56 days the
eggs hatch. (Mediterranean tortoises take about the same length
of time to hatch but are much smaller eggs; the Elongated tortoise
eggs take about 150 days.) This followed on observations at Honolulu
Zoo which showed that the females gathered leaf litter and other
loose vegetation into a mound which composed down generating the
heat necessary to incubate the eggs. If the female cannot find a
suitable site she may retain the eggs too long and they will cease
to be viable.
After
laying, instead of wandering off until the next time like most tortoises,
the Burmese Brown female patrols the nest site, evidently on guard.
Because of our damp climate, we have to move the eggs to our incubator
room, but her behaviour begs the question - just how long does
she remain on guard? Is it until the smell dissipates, or does
she remain until the young are hatching and perhaps even (in the
manner of crocodilians) assist in some way - possibly by clearing
away some of the overlying compost?
The
eggs are slightly larger than table-tennis balls, and the newly
hatched tortoises are extremely small and need very careful rearing
if they are to survive and develop properly.
The
biggest threat to the Burmese Brown tortoise, which in the wild
ranges from Assam in India eastward to Burma, down through western
Thailand and on south through Malaysia as far as Sumatra and Java,
is capture for food.
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