A successful blue-tongue
skink caesarian.
HerpVet, Dr Joshua Llinas, must perform
emergency surgery to save a pregnant mother and
her offspring.
Late in the breeding season, a very pregnant blue-tongue
skink (Tiliqua scincoides) is starting to struggle with the
pressures put on her body. The large number of foetal
skinks is taking its toll, as the sheer mass of the offspring
reduces her ability to eat, breathe and maintain her
immunity. Although this is a normal part of the blue-
tongue reproductive physiology, sometimes, as in all
animals, it can be too much for them, resulting in devas-
tating consequences. The goal of this article is not to talk
about the breeding process but to give a better under-
standing of what is happening during the long gestation
of these viviparous skinks, the changes in their behaviour
during the later stages of pregnancy, and what to do when
things don’t go plan. Although rarely required, the
individual circumstances in this case resulted in the need
for a caesarian to be performed to improve the chance of
survival of the female and her offspring.
How did we get here?
It all started with an enticing twitch of the tail by the
female. The male will reciprocate by biting her on the
neck in an attempt to hold her in position. When all
works well, the female will lift her tail allowing the male
to position himself correctly for mating. On average,
copulation will last for 30 to 90
seconds.
grow to fill the space in the female’s coelom (abdomen)
leaving little room for anything else. It is obvious from
x-ray images that the lung space is significantly reduced
in the pregnant female compared to that of the non-
pregnant one (images 1 and 2). This becomes important
when trying to understand the stress put on the female’s
body and why, in some cases, intervention may be
required.
The impacts of the foetuses on the female have been
studied in another Tiliqua species, the Shingleback
(T. rugosa), and the energetic cost of breathing in late
pregnancy was shown to increase by over 60%. Breath-
ing is an active process in skinks that requires using
multiple muscles to help expand the lungs. Due to the
decrease in space, the lizards need to increase their
respiratory rate to compensate and this uses more energy.
It has been shown that, in these later stages, the female
has a reduced ability to respond to the increased respira-
tory demand during exercise. During late pregnancy, the
female, with little reserve but still needing to breathe,
will conserve energy in other ways, such as minimising
movement and decreasing food intake. These and other
stresses can reduce the female’s immunity, increasing the
The developing blue-tongue
embryos have the majority of
their nutrients supplied through
the yolk (lecithotrophy) with
some additional nutrients, gas
exchange and fluid supplied
through a placental-type attach-
ment (placentotrophy). Over the
course of 100-120 days, the
female will support the develop-
ment of the foetuses, allowing
them to fully develop before she
gives birth. The foetuses
(usually 8-10 but up to 20) will
1. Female blue-tongue in late-
stage pregnancy. The skulls of
the babies are clearly visible,
and lung space is significantly
reduced.
2. Non-pregnant female for
comparison. All images
courtesy of Dr Josh Llinas.
1.
2.