Reproduction and Birth

Modes of Reproduction

Several method of birthing exist in reptiles:

Oviparous - egg laying - Young develop in a shell nourished by the egg yolk independent of a host
Ovoviviparous - live bearing - similar to viviparity in that the embryo develops within the mother's body but the young are nourished by the egg yolk
Viviparous - live bearing - the embryo develops within the mother's body gaining nourishment from the host (mother).

Many owners of Tiliqua and other reptile genus' may be confused to the modes of reproduction in reptiles. Confusion exists not between "egg layers" and "live-bearers" but between the two types of "live-bearers:" viviparity and ovoviviparity.

I am sure many of you have thought of reasons why viviparity exists in reptiles as a larger majority of reptiles seem to be oviviparous due to their exothermic nature while a significant less are ovoviviparous. The least common in reptiles is the viviparous mode of reproduction however a stunning percentage (less than 50%) of all skinks are viviparous. My own personal research to the ontogeny of reproductive methods of tiliqua has uncovered that "there has been much research and discussion about the selective pressures leading to the evolution of viviparity (e.g. Shine, 1983) and it is now well established that viviparity is favoured in cold environments" (Thompson, 2002). The first general study done of viviparity in Australia was in 1920's by H. Claire Weekes who use "light microscope histology to describe the structure of the chorioallantoic placenta of 13 species of Australian skinks" of which the genus Tiliqua was a part of "and four snakes" (Harrison and Weekes 1925-1935 in Thompson, 2002). Weekes' research indicates that "most species have simple chorioallantoic placentae where a more or less shell-less egg comes into close association with uterine tissue with no elaboration of structures on either the embryonic or maternal sides of the placenta" (Thompson, 2002). These she termed "type I placentae" (Weekes 1935). It was exceedingly interesting to note that there are four types of placentae in all each with a higher degree of sophistication, complexity and interaction with the growing embryo. The genus Tiliqua "are all viviparous with simple placentae" (Weekes, 1935 in Thompson, 2002) which is categorically defined with the general term of viviparity. It is truly exciting to see how sophisticated our blue tongue skinks are when the presence of placentae intimates a degree of transference and dependency between embryo and parent as in many higher life forms and mammals.

Baby Identification and Differentiation

Many people, due to their lack of experience and exposure to many T.S.Scincoides and T.S.Intermedia adults and offspring, get them repeatedly mixed up with Irian Jayas (T.sp). I have placed newborn Irian Jaya pictures along side my Tanimbar, Easterns and Northern newborns in hopes that those reading will see the ostensible differences between them. Irian Jayas have very clearly defined banding with no speckling at all in the center of the banding. Northerns have speckling on alternating banding or throughout the top layer and appear to have more layering in their coloration from their backs to their sides. The classic Northern "port-hole" are a dead give away that they are Intermedia but may be difficult to assess to those less experienced in dealing with newborns. I also would like you to pay CLOSE attention to the hybrid page and note an Irian Jaya and Northern cross of which there are several examples. Some people can misidentify their skink as a pure Intermedia but in actuality it's a cross.

Indonesian newborns (T.G.) look completely different from Irian Jaya and Australian skink newborns so anyone claiming they have tiliqua knowledge misidentifying them for anything but T.G. needs serious glasses and/or serious ego reduction via hammer. Note: identifying the differences between T.G.E., T.G.K. and T.G.G. newborns is all together a different matter. They seem to be extremely similar until they mature. I will eventually confirm this information with future research in this matter.

Approximately 4 months later after initial conception babies are born viviparously.

They either shed immediately or flake off the birthing membrane; the consistency of this "shed" resembles that of rice paper and equally as fragile. See Fig 1 of a 2006 Tiliqua scincoides intermedia newborn and Fig 2 of Jean's baby (T.S.I.) born on 7-1-06. I will capture this "shed" and put it under a microscope this year for analysis.

They neonates are born with a thin membrane around them which breaks during parturition. I have also seen a wonderful mother break the skin of this membrane herself. I was afraid she was going to kill the baby but I was wrong! It's quite a cute thing to see the mother nudge the baby, encouraging them to move and escape from their translucent prisons.

The female should be separated from any other animal - actually bts should be housed individually. Placing the female on different substrate is advisable but not necessary as the babies will eat their afterbirth IMMEDIATELY after being born.

Litter is often stuck to this afterbirth which gives me fits when I try to pluck off the debris as the little baby greedily gulps down the messy goo.

Note: All mothers pictured with their babies are taken immediately after birth. Babies when possible are normally housed separately to prevent conflicts between conspecifics.