One day in late May we took Célestine over to mechanic Jean-Louis in Chateauroux. When we walked down his driveway to go to his workshop an Asp Viper Vipera aspis (Fr. Vipère aspic) slipped between us and went under Jean-Louis' Traction which was parked there.
You can see how much the tail narrows in this photo.
Jean-Louis and I immediately whipped out our cameras and started shooting. The snake regarded us with equanimity, calmly swaying from one side to the other but not hissing or striking out. Finally it decided it could not risk moving past us into the undergrowth and chose to climb vertically up the inside of the driver's side rear wheel. Jean-Louis didn't want it taking up residence in his car but it wouldn't budge. Finally we rolled the car forward slightly and it dropped down again.
A protected species, Asp Vipers are the only venomous species of snake in our area of France. They are relatively abundant and found in scrubby areas (Jean-Louis doesn't do much gardening...). They kill their prey by delivering a toxin when they bite, and bites to humans, which they will attempt as a defensive measure, can be fatal.
You can see the vertical slit pupil in this photo.
This is a medium sized snake, with the distinctive viperine triangular head, vertical pupils and snub up tilted nose. It has a fairly typical zigzag black pattern down its back, and doesn't grow beyond a metre long (mostly being half that size, like this one). Vipers have quite thick bodies that narrow noticeably at the tail. They can be confused with the Viperine Snake Natrix maura, a non-venomous grass snake that is similar in colour and pattern, but has round pupils and is more slender and if adult, longer. If you see a snake that looks like this swimming, it will almost certainly be a harmless Viperine Snake and not a true Viper (although they can and occasionally do swim).
Asp Vipers are diurnal, and active between February and November. They give birth to live young in August and hibernate over winter in natural cavities. Their main prey are small mammals (voles, field mice, shrews), lizards and birds. They like habitat that is transitioning between open and wooded, and are less present in intensively cultivated areas. They also like dry rocky scrubby slopes and the damper habitat of bocage (small fields of pasture surrounded by hedges). Their presence or absence is linked to the presence or absence of their small rodent prey.