Olive Whip (grass) Snake
On almost every occasion that I have been called out to collect a positively! Identified ‘black mamba’, from someone’s house or garden, it has turned out to be an Olive Whip or Grass snake! They are fairly large, robust snakes, sometimes getting up to almost 1,8m in length. They are usually a darkish brown on top with well defined scales and a yellowish white underneath and are very fast moving, so if you picture a mamba as being a big black, fast moving snake, then you are quite likely to believe these snakes are mambas!
However, to anyone who knows a little about snakes the Olive Whip Snake and the Black Mamba are very different. To start with mambas are normally olive green/brown or slate grey in colour and are unlikely to be found in built up areas. I have yet to find a black mamba in the built up areas of Harare in 35 years living here! Olive Whip Snakes, on the other hand, are much more common and often encountered in the garden. They are found throughout Zimbabwe except for Nyanga. Like the rest of the body, they have a darkish brown head and the throat is very distinctly speckled.
Younger specimens usually have a pale narrow line down the centre of the back.
Olive Whip Snakes are gregarious and often live in colonies. I have on several occasions found five or more of them living together in an anthill. On one occasion a snake, identified as a mamba! was seen disappearing down a hole in an anthill. As the hole was dug up we came across the snakes, (olive whip snakes) one after the other.
As each was dug up they made a dash for the long grass about five meters away which was unfortunately behind a fence that was very difficult to get through. The end result was that only one of them was caught! These snakes have the habit of stopping as soon as they reach cover, often with the end of the tail still exposed.
The young prey mostly on frogs and lizards whilst the adults prefer rodents and occasionally other snakes. They have even been known to eat young black mambas! The younger snakes can often be found foraging for food in vleis and swamps whilst the adults will be found wherever there are rodents. The females lay up to 40 eggs around October which hatch up to 5 months later.
The Olive Whip Snake is a back-fanged snake and although they are not considered dangerous, a bite from a large one, which they do readily, can produce quite severe symptoms – a lot of pain and bleeding at the site, followed by nausea and headaches. After one particular bite I experienced blood clots in the urine about two weeks later, consistent with a subsequent vine snake bite. (They come from the same family). A very high percentage of Olive Whip Snakes are found with truncated tails, for some unknown reason.
The short snouted whip snake (Psammophis brevirostris), is similar in appearance to the Olive Whip Snake but not as robust and only attaining a maximum length of about 1,4 m. they are often found in the Eastern Highlands and on high ground between Harare and Mutare in open grasslands
Another member of the Psammophis genus is the Montane or Cross marked whip snake (Psammophis crucifer). In Zimbabwe they are found only in the Eastern Highlands between Nyanga and Chimanimani. They are small snakes, reaching a maximum of about 700mm. Like all the other sand or whip snakes, they are diurnal and have a round pupil.
The back is silver grey in colour with a broad black-edged brown stripe down the centre. There are similar stripes on the flanks with a white lower edge and the belly is yellowish orange. The head is boldly marked with creamy yellow cross bars that are dark edged.
They prefer the open short grassy areas that you find in Nyanga and Chimanimani and although they wriggle a lot when first caught they seldom attempt to bite (unlike the Olive Whip Snake). They prey mainly on lizards and sometimes frogs.