By Sahra Kress, Community Midwife, 20 September 2022
As a midwife, I have witnessed amazingly diverse births over the last 18 years, ranging from births in the hinterlands of Papua New Guinea, in the slum hospital of Vanuatu, to grass huts in the Solomon Islands. I have attended births on the linen couches of gorgeous New Zealand homes, in house-trucks, ambulances, or with the urgency of lithotomy beds or operating tables. But the unique and exceptional circumstances of this birth I could never have expected.
It was a strikingly beautiful sunny afternoon. I was looking after my two nephews, three and five years old, and as usual we headed out into nature- our favourite thing to do together. We decided to go to Ngā Manu (A nature reserve near Waikanae, Kāpiti Coast, Aotearoa New Zealand), largely because the three-year-old had been talking for months about the tuatara at Ngā Manu who we saw twice “sitting in his puddle and sticking his tongue out!” Somehow, my nephew just thought this was hysterical and it became a sort of joke each time he saw me.
Also, I wanted to go see what skinks and geckos they have at Ngā Manu because I had recently become extremely interested in lizards and their amazing viviparous reproductive state (they give birth to live young!) after becoming involved with the potential Lizard Sanctuary planned for the reserve at Queen Elizabeth Park. I was particularly fascinated by the question of whether lizards have placentas (they do, and quite a developmentally complex reproductive process).
When we arrived, I asked the front desk staffer about the lizards at Ngā Manu and explained my recent recruitment to the Lizard Sanctuary project. She confirmed that geckos were in the display cases just outside. We wandered over, and as the gorgeous afternoon light poured across the glass, it was easy to see the Green Barking Geckos sunning themselves in the warmth. I had never seen them so close and enjoyed inspecting the detail of their beautiful emerald scales, their fine narrow tapering toes without pads, and their long powerful tails.
Under one of them, off to the side, I noted a strange extra feature. Just under the abdomen, at the juncture of the tail, there was this strange pinky/brown thing.. it looked a bit like a blob and my mind inadvertently thought “that looks like a placenta”. And the gecko was heaving. I watched in fascination, feeling that I was witnessing something altogether familiar.. could it be? That must be a membrane sack..
And there, just behind her, was the tinies, fragile little baby. Absolutely delicate, covered in reddish mucus and very wet, about 2cm long. I rushed back to the front desk to ask the staffer whether she knew that they had a gecko delivering. She immediately called in various rangers who all came quickly, and we watched, marvelling as the tiny gecko baby uncurled its miniscule tongue, flicked its tiny needle-like tail. The baby had the same white facial markings as the mother around its mouth, and initially the mother had turned and seemed to sniff or nuzzle it a bit. Would there be a second baby still? They often deliver twins.
Over the next hour, visitors became alerted to this special event, and the rangers prepared a little creche for the baby, to help nurture it in its own environment. We left feeling utterly delighted, so privileged to have seen this special birth. What an absolutely extraordinary thing to have witnessed.
And it absolutely convinced me, yet again, of the importance of restoration and conservation efforts. These unique animals are so fragile and threatened.
Some interesting points from my research precipitated by this experience:
- Viviparity (giving birth to live young) applies to 99% of NZ lizard species.
- Pregnancies usually last about 3 months but are temperature dependent and may reach as long as 14 months in some geckos.
- Some NZ geckos can retain fully formed offspring in utero over winter and can start the ovulation process prior to the pregnancy ending.
- Each conceptus starts with a yolk mass complex. This develops into a placenta that forms from close apposition of the extraembryonic membranes to the uterine lining.
- In the wild, there are high rates of failure in embryonic development, resulting in high numbers of abortions and ‘stillbirths’, as well as over-gestated foetuses. These result from various (speculated) causes.
- Some geckos can live 30-50 years in the wild.
- The time for baby lizards to reach sexual maturity ranges from two years from birth to eight years for some larger species.
- NZ lizards can regrow their tails if severed.
- There is increasing evidence that certain species of NZ lizards show some form of parental care, or at least tolerance of their young. Some live in family groups in the wild.
- They have extremely low annual successful reproductive rates.
References:
Cree A., Hare K.M. (2016) Reproduction and Life History of New Zealand Lizards. In: Chapple D. (eds) New Zealand Lizards. Springer, Cham. https://doi.org/10.1007/978-3-319-41674-8_7
Winkel, D. van, Baling, M. & Hitchmough, R. (2019). Reptiles and amphibians of New Zealand: a field guide. (2019). Auckland University Press.
Department of Conservation:
https://www.doc.govt.nz/nature/native-animals/reptiles-and-frogs/lizards/
The New Zealand Herpetological Society: https://www.reptiles.org.nz/
(Based on the article published in the Forest & Bird Magazine, Spring Edition, 2021)
