[4][5] Two populations formerly included in this species are now recognized as separate: the larger and less strongly coloured F. major from southern Madagascar, and the typically greenish (it is not generally found in a dark, blackish form) F. viridis from western and northern Madagascar.

[7] It can be found between 120 and 1,925 metres (394 and 6,316 ft) above sea level, and inhabits forests, shrubby areas, grasslands and well-vegetated gardens.

Both sexes have stripy throats and lips, and the side of their body has a lateral line and several ring-like markings.

They can change their colour depending on their mood (pregnant females in particular are strongly marked) and environmental factors and they usually start the day with a dark colour to enable them to warm up rapidly by exposing themselves to sunlight.

Females lay between eight and twenty-three eggs at one time, and can produce up to three clutches a year.