07 August 2014

Diadem Snake – Record by Cliff Paterson

The Diadem Snake Spalerosophis diadema is named for its distinctive head markings, consisting of a dark band, which runs across the head between the eyes, behind which several irregular, dark spots may be present. The background colouration of the head and body varies between individuals but is usually greyish, yellowish, sandy-beige or reddish and measures up to 180 centimeters in length. A series of dark brown, olive or reddish blotches runs down the middle of the spine, which fuse into a dark stripe at the neck. In addition, the flanks are marked on either side with a row of smaller dark spots. The head is elongated and slightly triangular, with a rounded snout and large eyes featuring circular pupils. An active predator, it predominantly feeds on rodents, throwing a loop of its body over its prey to immobilise it, before delivering a suffocating bite with its powerful jaws and also produces chemical secretions from an oral gland, which are highly toxic to small mammals, but pose no danger to humans. In addition to rodents, the Diadem Snake is also known to prey upon lizards such as agamas, and occasionally on small birds. When threatened this species is known to inflate and thrash its body, hiss and make rapid strikes. Theses snakes change their activity period according to the season, being diurnal during the winter, autumn and spring, and nocturnal and crepuscular during the summer. They often rest amongst stones, loose rocks, desert plant roots or in rodent burrows during the day to avoid the extreme heat. The Diadem Snake has a large distribution, occurring throughout northern Africa from Mauritania to Egypt, the Arabian Peninsula including Saudi Arabia, and southwest and central Asia, as far as Kazakhstan, Pakistan and India. They are found in arid and semi-arid areas, including stony and sandy desert, and frequently occur in cultivated areas and palm groves surrounding oases. It can be found from lowland regions to elevations of up to 2,000 metres.

It was about 1.5 meters in length and aggressive. Cliff sent me the following details of his encounter with this snake. We had camped in Wadi Nisah during the winter when air temperatures fall rapidly with approaching sunset. We were driving back to our campsite just as the sun was on the horizon when I spotted the snake and drove towards it stopping well short assuming it would flee the approaching vehicle. The 3 of us hopped out and proceed toward the snake. I had parked in a sliver of sunlight and a deep shadow cast by some rock separated us from the snake which occupied another sliver of sunlight. As we approached the snake, it turned and aggressively started directly toward us. I have never encountered such aggression in a snake. Amazingly, as it tried to cross the shaded area in pursuit of us, the temperature had already dropped enough that the snake's forward progress to be stopped.  I emptied my Pelican case and ever so carefully collected it into the case where it spent the freezing night. We broke camp the next morning, posed the snake for its photo session, then departed before it had warmed in the sun.