Bocage’s Wall Lizard (Podarcis bocagei) is only found in the NW corner of the Iberian Peninsula, including Galicia, Spain. It is a small lizard which is often seen on wooden broad-walks, where it pops up to bask in the sunshine. They quickly disappear beneath the planks when heavy footed humans get near!
The sexes are differently coloured: the mature males have a green upper (dorsal) surface, whilst the females have a brown one, usually! As well as a green back, the males also have brown flanks (as shown below). These little lizards only live for about four years. The males quickly turn green once they have reached sexual maturity, and have only 2-3 years as an adult (1).
Many animals, from butterflies to lizards, are faced with conflicting demands in terms of their biology. Whilst they need to remain hidden – inconspicuous and cryptically coloured – to avoid predation, they also need to be bright and conspicuous in order to signal their sexual prowess, or fitness. Males are usually, but not always, the sex which signals their overall genetic fitness in terms of bright colouration and showy displays. The females choose who they want to mate with, based on these colours or displays.
I took these photo (top and below) of nice bright green male Bocage’s Wall Lizard (Podarcis bocagei) in May (top) and June (below). The breeding season runs from April to July. They usually let me get quite close; they do not want to move out of their warm, sunny spot unless they have to!
Breeding males also turn a bright yellow colour on their under (ventral) sides, during the reproductive period. Unfortunately, I was not quick enough to catch this one and turn it over! It is difficult enough to get sufficiently close to get a good photograph.
Somewhat confusingly, a small proportion (less than 10%) of female lizards of this species turn green after mating, particularly in coastal areas (2). I blogged about this phenomenon before. So it’s possible he is a she! And the one above does look quite fat, as though it was gravid (pregnant). Some things I guess we will never know!
Photographs taken near Morouzos beach, Ortigueira, Galicia, Spain.
- Galán, P. (2008). Ontogenetic and sexual variation in the coloration of the lacertid lizards Iberolacerta monticola and Podarcis bocagei. Do the females prefer the greener males?. Animal Biology, 58(2), 173-198.
- Galán, P. (2000). Females that imitate males: dorsal coloration varies with reproductive stage in female Podarcis bocagei (Lacertidae). Copeia, 2000(3), 819-825.
I am an entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.