Supplementary Table. Action elements used in nettle processing at Port Lympne[i]
Actions for procuring items
hook[ii]whole hand or only some fingers (specify) held rather rigidly in open curve to pull attached object (often used to heave down mass of vegetation).
reachiivarious sorts of grip on attached object, which is pulled to bring into range (often used with a similar function to hook).
pickpinch-grip on clearly defined object which is pulled against force of natural attachment, usually to procure the item.
Actions for detaching parts from items
pull-apartparts of an object held in the two hands (whatever the grip), the hands then pulled apart in a movement at a tangent to body, thus applying force to object.
lever-apartobject (usually leaves) held in both hands using power-grips, then leverage of rocking the hands or knuckles against each other used to tear the object.
twist-apartobject (usually leaves) held in both hands using power-grips, then twisting of each hand versus the other used to tear the object (often hard to see if twist-apart or lever-apart).
strip-uphalf-open power-grip (often constricted at 1:2, but not always) around leafy stem, slid up stem towards body to detach bunch of leaves, against force of substrate or other hand's supporting grip (thus accumulating leaves, the bunch protruding between 1:2) Sometimes movement in reverse direction, away from body, when constriction normally at 5:palm.
tooth-strippartial closure of incisors around root or stem, pulling against support of hand(s), an action like that of wire-strippers.
bite-offuse teeth to cut off portion of naturally attached or hand-supported object [mainly a stem-processing technique].
Actions for manoeuvring items
combineiiability to carry out separate functions with fingers 1.2 and 3-5 at same time(in various functions), e.g., pinch-grip with 1:2 to pick while loose-grip of 3-5to accumulate already picked items.
two-handed-bendloosening and re-grasping by the hand holding a long item, while item is folded into a bundle with the other hand, either once (S), or many times to form a concertina shape (R).
five-finger-squeeze[iii]a bundle of leafy material or a leafy stem, already held with a loose grip in one hand, is squeezed using a rolling motion of the fingers of that hand, the digits 5 → 2 successively closing over the leafy material. When used on detached leaves, where it may be combined with adjust-position with the other hand,this results in a compacted bundle; when used on a leafy stem, this results incrushing the leaves around the stem before insertion into the mouth for sausage-feed. (Unimanual.)
pick-outpinch-grip or lip-grip on small item which is pulled off an object or out from among a mass of items, requiring discrimination of one item from among many (such as in cleaning a food handful, or accumulating a bundle of food items).
adjust-position[iv]a pinch grip is used to make fine adjustments to the position of a bundle or occasionally a stem, by turning/rotating in order to allow processing of all surfaces. (With a stem, one end - usually just protruding from a loose supporting grip in the other hand - is rotated using a pinch grip.)
adjust-push-iniiieither knuckles or a pinch grip used to compact loose leaves, in a bundle being supported in the other hand; used for tidying a bundle.
tuck-iniiithe thumb or occasionally the index fingeris used to compact a bundle, already held in the palm by tucking in protruding leaves; normally follows strip-up. (Unimanual.)
Special ways of biting
shear-biteshearing bites used to slice off slice of a large, compact handful of items, either singly (S) to finish eating a handful (when remains discarded unless retain-nucleus) or repeated (R) in order to eat entire handful.
pop-in[v]place processed food bundle into open mouth with pinch grip, avoiding lip contact
sausage-feedrepeated loosening grip and re-grasping lower down an approximately sausage-shaped food bundle, in order to feed it into the mouth as a whole (without the bundle coming apart). Only observed by Byrne and Byrne (1993) for leaves, but here also used for stems, when almost always fed in backwards i.e. root end first with back of leaves facing mouth, and often after the leaves were compressed around the stem with five-finger-squeeze. On the rare occasions when the stem was in forwards, this was done very slowly, and only with stems where the majority of the leaves have already been removed. During sausage feeding, lips were pulled back and thumb was often extended into the side of mouth, perhaps helping protect sensitive lips and to guide bundle along between teeth rather than into centre of mouth.
retain-nucleusiiusing the remains of the last handful eaten (bitten off from these remains with a shear-bite) as a basis for starting to accumulate the next.
[i] Definitions unaltered from Byrne and Byrne (1993) and Byrne, Corp and Byrne (2001), except where explicitly noted.
[ii] Used rarely: although recorded during the study, the criterion of use on >5% of occasions meant that this action does not occur on any of the flow-charts.
[iii] Not described by Byrne and Byrne (1993).
[iv] Modified from Byrne and Byrne (1993), by splitting the less precise adjust.
[v] Not explicitly described as an element of action in Byrne and Byrne (1993) or Byrne, Corp and Byrne (2001), but the normal way mountain gorillas eat processed nettle handfuls.