Siafu is the Swahili word for a group of ants, also know as soldier or army ants, driver ants, and safari ants.
When I was a young girl, living in Kigoma, a large army of these ants marched through my bedroom during the night while we were asleep. Mum spent a long time dousing me in kerosene and picking them off with tweezers. Ouch!
Seasonally, when food supplies become short, they leave the hill and form marching columns of up to 50,000,000 ants, which are considered a menace to people, though they can be easily avoided; a column can only travel about 20 metres in an hour. It is for those unable to move, or when the columns pass through homes, that there is the greatest risk. Their presence is, conversely, beneficial to certain human communities, such as the Maasai, as they perform a pest prevention service in farming communities, consuming the majority of other crop-pests, from insects to large rats. (Wikipedia)
Recently we have noticed these ants in our yard.
Noticed the hard way.
I was hanging out some washing and felt an incredible stinging over my feet. There was a lot of stamping and slapping that followed.
Yesterday I was fascinated to watch some siafu divide and drag away a dead slug.
Here is an interesting fact I read about them today:
Such is the strength of the ant's jaws that, in East Africa, they are used as natural, emergency sutures. Various East African indigenous tribal peoples (e.g. Maasai moran), when suffering from a gash in the bush, will use the soldiers to stitch the wound by getting the ants to bite on both sides of the gash, then breaking off the body. This use of ants as makeshift surgical staples creates a seal that can hold for days at a time, and the procedure can be repeated, if necessary, allowing natural healing to commence. (Wikipedia)