[7] This species, A. desaixi, is named in honor of Frank DeSaix, an American Peace Corps volunteer who collected the first specimen.

The rostral scale is not as wide as it is long, while its upper margin is highest at the center.

This darkens as they grow until they reach the adult color phase at a total length of about 30 cm (12 in).

[4] In this environment, their coloration offers them an excellent camouflage, making them very difficult to spot.

It is obviously arboreal, moving slowly and deliberately among the branches of its habitat as other Atheris species do, but it is unknown when daily peak activity occurs.

It may also perform a characteristic, stridulating threat display, in which counterlooped coils and the lower serrated, keeled scales are rubbed against one another to produce a loud hissing noise.

[4] A. desaixi is reported to be an opportunist, preying on amphibians, rodents and small birds.

[4] A gravid female specimen of A. desaixi found in the Nyambeni range is reported to have given birth to 13 offspring in the month of August.

[1] The Kenyan who collected the first specimens was bitten by an adult, with a single fang penetrating his right index finger.

A tourniquet was applied and an unknown antivenin was administered, after which the patient made a full recovery.