The developing marsupial
provides an easily accessible model for studying development in a
non-invasive manner which could not be achieved with placental mammals.
Marsupial joeys are ectothermic at birth and develop endothermy whilst
in the pouch. Blood gases and pH are believed to be regulated
differently in ectothermic and endothermic animals by α-stat and pH-stat
regulation respectively. This project aims to use Tammar wallaby (Macropus
eugenii) joeys to characterise how blood parameters are regulated in
an ectothermic mammal and during the development into an endothermic
mammal.
For comparative purposes
a truly ectothermic animal, Rosenberg’s goanna, and a true endotherm,
the Zucker rat, will also be studied.
Heterothemic marsupial model
Mammalian body
temperatures are generally confined to a narrow range except during
hyperthermia or hypothermia. Heterothermic mammals (such as squirrels,
and dunnarts) undergo periods of regulated temperature reduction during
torpor or hibernation bouts. There have been extensive studies
investigating blood acid/base balance during torpor in placental
mammals. The fat-tailed dunnart (Sminthopsis crassicaudata)
colony at LTU provides an opportunity to study the effect of torpor on
the acid/base balance and other blood parameters in a heterothermic
marsupial.
