St. Patrick may have been able to expel all of the serpents from Ireland (not really, they just never made it there), but he missed a little lizard by the name of Zootoca vivipara, the Viviparous or Common Lizard. Although a few marine reptiles grace Ireland's shores, including Leatherback (Dermochelys coriacea), Hawksbill (Eretmochelys imbricata), Kemp's Ridley (Lepidochelys kempii), Loggerhead (Caretta caretta), and Green Sea turtles (Chelonia mydas), and the introduced European Slow-worm (Anguis fragilis) may remain hiding in the Burren of County Clare, Z.vivipara is the only native terrestrial reptile found in Ireland. Despite a broad distribution (see map below) across Ireland, this little lizard continues to be a surprising find, even for those who live, or have lived in Ireland (my dad included).
Ireland doesn't seem like a particularly hospitable place for a small lizard, but Z.vivipara manages to persist in much colder climates. The range of this species spreads from as far west as the Emerald Isle and as far east as Japan, crossing through Russia, Mongolia, and Kazakhstan. They extend down into the Iberian Peninsula, across the northern reaches of the Mediterranean, and north into the nordic countries of Sweden, Norway, and Finland. The amazing success of Z.vivipara, is likely due to their ability to frequently reinvent themselves. As an adaptation to a broad range of climes, the Viviparous lizard is both oviparous (egg laying: France, Spain, Italy, Austria, Slovenia), and viviparous (live birthing: rest of range, and some overlapping regions). Perhaps most interesting is that the switch from oviparity to viviparity has happened more than once (Surget-Groba et al., 2006).
We found Z.vivipara along the southern coast in coastal heath along the cliffs of Ballycotton. A nice sunny day brings these sluggish little guys out for a bit of basking, and wherever there was a break in the clouds, there were several Viviparous lizards piled up like solar panels. That's all for now, but maybe I'll return to talk a bit more about the biogeography of Ireland, and why its herpetofauna is so depauperate compared to the rest of the British Isles.
Farren, A., Prodöhl, P.A., Laming, P., Reid, N. 2010. Distribution of the common lizard (Zootoca vivipara) and landscape favourability for the species in Northern Ireland. Amphibia-Reptilia 31: 387-394. Download.
Surget-Groba, Y., Heulin, B., Guillaume, C-P., Puky, M., Semenov, D., Orlova, V., Kupriyanova, L., Ghira, I., Smajda, B. 2006. Multiple origins of viviparity, or reversal from viviparity to oviparity? The European common lizard (Zootoca vivipara, Lacertidae) and the evolution of parity. Biological Journal of the Linnean Society 87: 1-11. Download.