Triadic and collaborative play by gorillas in social games with objects

Abstract

Interaction with others over objects has until recently been thought lacking in the social play of non-human great apes, in contrast to that of children; even now, only bonobos have been observed to engage in social play involving objects. Human children’s triadic interactions with objects involve joint attention, showing and giving, communication that maintains interaction, and sharing of emotions and experiences. We question assertions that chimpanzees, and non-human great apes in general, lack the key characteristics of children’s collaborative play. Here, we show that zoo gorillas play games that are both triadic and collaborative. These games were videotaped at the San Francisco Zoo in five different years and involved five different pairings of gorillas. The context was in most cases playfully competitive, involving objects such as balls, bags and leather pieces as foci of joint attention; the ostensible goal in most games was to gain or keep possession of a particular object. In some episodes, roles as possessor or pursuer of an object were exchanged many times; in others, one gorilla retained possession of an object but encouraged pursuit from a partner. Through gaze and gesture, gorillas invited others to: share interest in and attention to objects; share patterns of play; and re-engage after breaks in play. Sometimes, gorillas would assist others in their efforts to engage in collaborative play: older gorillas encouraged younger partners by ‘self-handicapping’ their own actions. Collaborative games may occur later in the ontogeny of gorillas than in humans, and depend on the challenges and artifacts available in a particular group’s habitat.

Appendix: Narrative descriptions of Games

Key engaging actions, including gaze and gestures, are italicized in the descriptions; key behaviors selected for analysis are indicated within narratives by the following codes (see “Method: Analysis for definitions”): Joint activities JA, Gaze alternation GA, Gestures used during game GG, Other-oriented actions with objects OA, Help others HO, Re-engage partner RE.

Game 1: 2/27/89

Excerpts from a 26.42-min episode. Kubie (K), male, age 13; Zura (Z), female, age 7.

Theme of game: (JA) Kubie, to retain possession of a burlap bag, Zura, to grab it. K tries to get Z to come and engage physically with him without leaving his burlap bag “base” for the duration of the episode. Z has a perch of her own on a rock perhaps 3 feet away to which she regularly retreats as her home base.

Starting the game: Scene begins with Z on a burlap bag, then tugging on the burlap bag as K puts his fists on it on the ground. He stays on it when Z lets go of it to wrestle; when she retreats to her perch he spreads the bag out carefully and stands on it quadrupedally.

Maintaining engagement: K stays on a neatly placed burlap bag as he entices Z to him from her rock perch with gestures and display; they intermittently wrestle. (OA 12.41; GG 0.52, 1.06; GA 0.25, 1.47, 2.22, 3.12, 3.42, 12.18, 12.30, 13.27, 24.20, 25.27) K turns Z around and pushes her back into her rock perch at 3.07 (JA; awareness of Z’s home base as well as his.) Z hides her playface several times at the beginning of the interaction (0.13, 00.26, 0.49), regulating the onset of contact (as in Tanner and Byrne 1993). Another regulatory action by Z occurs at 9.10; Z places K’s hand on the ground and holds it, presumably to keep it still instead of continuing wrestling, then presents her rear to him and he puts his hand to her rear.

K keeps at least one foot on the bag or holds it in his hands at all times and straightens and smoothes the bag between rounds of wrestling. Z gestures, frequently armshaking, several times presents her rear, and makes several “sneak attacks” from behind as she persists in trying to snatch the bag, more and more frequently as the game progresses.

Re-engaging after pauses in game: (RE) Z goes away from K and turns her back, 3.15. At 3.45, K rips the bag open noisily (OA); Z runs past him to top of rocks, he grabs at her as she goes past but misses; he rips the bag more and spreads it in a semicircle around himself. Z stays on top of rocks and chestbeats several times, looking down where K is; at 4.48, K gestures from below. There are many short pauses where one or the other gorilla gestures from its base and then both resume activity around the bag GG, RE 5.19; 6.14; 8.32, 8.50; OA 12.41. After a rather long break, at 17.03, Z armshakes, chestbeats, and goes to K who immediately picks up his bag and hugs it protectively. After a break, when K has run from the rock play area to the grassy field, he returns to the rocks “wearing” the bag across his back, only picking it up with his hands when he returns to the rocks and Z, and then shakes the bag in front of her (OA, 22.02).

Ending the game: 24.56 Z is seen on top of the rocks. (GA 25.17) K carefully rearranges his bag in a semicircle around him, knocks on the rocks and looks up at Z and down at the bag. He waits, at 26.02 does a bipedal jump, roar and chestbeat. He looks up at Z again and waits; he sits, wraps the bag around him (OA 20.10) and looks up again. Zura does not return.

Indications that game focuses on a particular object: K always stays on or holds the bag. When Z’s attempts to grab the bag accelerate, he holds onto bag instead of sitting on it. Z gets a grip on the bag 11 times and several tug-of-war sessions ensue, but she never gets full possession. K positions the bag within Z’s reach, or shakes it in front of her (OA, 22.02, 24.19), or rolls it up and holds it protectively to his chest upon her approach (OA, 17.03, 24.10).

Game 2: 6/24/90

Excerpts from an 18-min episode. Starts 26.44, ends 44.10 on DVD. Kubie (K), male, age 14; Bawang (B), female, age 9.

Theme of game: (JA) Interaction with a burlap bag, non-competitive exchange of the object.

Starting the game: Though there has been playful interaction between Kubie and Bawang for at least 15 min prior to this episode, the bag game starts when K leans over the rock “table” with bag in hand, then drops it to put his hands on B. She sits back, picks the bag up, and puts it over her head and wiggles around beneath it (OA 27.42). K climbs off the table and starts to gently wrestle with B who is still under the bag. She removes the bag and hands it off toward K who takes it (OA 28.12), manipulates it a bit and then puts it over his hand and pats B’s head with it while she beats her stomach; then he play bites her head. The bag cannot be seen for a while, though K seems to be wrestling something on the ground, possibly the bag or B’s foot. The bag reappears, pushed by B toward K (OA 29.57); he puts it on his own head and shakes it (OA 29.58), then gently smacks B’s head with bag and she takes it (OA 30.04), then pushes it toward K again (OA 30.16). The game continues with the bag being a prominent part of the action. The entire episode takes place in an enclosed area of the rock structure. The camera angle means that sometimes faces are obscured.

Maintaining engagement: The two gorillas sit very close, face to face, the whole time. There is turn-taking with the bag and with many of the gestures and other actions (JA). The bag seems to be passed voluntarily from one to the other (OA 28.12, 29.57, 30.04, 30.16, 31.43, 32.28, 33.20, 34.27, 38.28, 40.18): one gorilla will push it toward or put it on the other, or take it from the other without objection. The bag is displayed in repeating ways like twirling in mouth (OA 30.32, 31.38, 32.22, 33.48. 41.10, 42.00), head shaking (31.38, 37.22, 39.29, 41.29) and head covering (27.42, 29.58, 31.04, 32.42, 33.51, 41.40, 42.40), and gestures of several kinds are shared and exchanged by both gorillas. There is much synchronization of actions, with rounds of simultaneous chestbeating, stomach, and even foot beating; and one round of beating is synchronous between partners even though K has put the bag completely over his head (32.37). A repeated element of the game is that after a bag display K playfully hits at B’s head; she several times anticipates this by shielding her head with hands before K brings his arms down to hit (JA 30.39, 31.55, 32.28).

Re-engaging after pauses in game: (RE) At a brief pause, K head nods abruptly, directing his gaze from B to the bag, then shakes it (GG, GA 30.30; GA 30.15, 32.21, 33.23); B joins in simultaneous stomach beating and foot clapping. First baby Shango, then the older female Pogo, strolls by and peers into the game area. K and B mostly ignore Shango but when Pogo pauses in front of them, K stops playing and stares (35.38). B after a few seconds beatsplayfully on his back, and he rolls over with a playface and starts wrestling gently with B again.

Ending the game: B rather abruptly leaves the rock area (43.02) and goes to sit in the doorway to the indoor quarters. (This appears to be related to an appearance at 42.10 by Pogo, who has been “babysitting” Shango; after this, B looks out toward doorway several times and seems distracted.) K continues to sit in rock grotto and shake bag and chestbeat, then goes out of grotto and looks toward B, bag still in his hand. She proceeds across grass followed by baby Shango, and the game never resumes.

Indications that game focuses on a particular object: Possession of a bag is exchanged 14 times between K and B and continually incorporated in displays and gestures. At several points, both cooperate in holding shaking a bag together (JA 30.20, 40.00).

Game 3: 8/31/92

Excerpts from a 9-min episode. Starts 44.10, ends 52.50 on DVD. Bawang (B), female, age 12; Shango (S), male, age 3.

Theme of game: (JA) To get and keep possession of a ball.

Starting the game: Shango appears with a ball, then disappears behind a rock formation followed by Bawang who was seated there. B emerges with the ball in one arm, running and twirling whole body with other arm as pivot, with S in close pursuit. The twirling serves both as a self-handicapping device slowing her down (HO 44.40) and allows B to meet S’s gaze regularly.

Maintaining engagement: B goes up onto the rock “table” with the ball, looking back at S. S climbs up on the rock, B goes down the other side and disappears behind the rock arch, comes back up on the table rock again looking back at S, jumps down again and into the arch. Each time B goes onto the rock table, she stops, looks, and seems to wait a moment for S to catch up before going on (HO 44.50, 45.03). She seems to stage the game to allow mutual participation.

Re-engaging after pauses in game: (RE) After another disappearance behind the rocks where he appears to be grappling with B, S emerges with the ball and climbs up on rock table (G 45.30). Bawang does not prevent him climbing up though she easily could do so and even appears to help him (HO 45.27). She remains below his higher rock; he bounces the ball then stops, facing B, and they mutually gaze for about 10 s. He bounces it a few more times with audible noise, then stands bipedally on ball, stretches both arms up and slaps upper rocks (GG, RE). At this, B stands up bipedally and grabs at the ball, but misses because S snatches it right up. He rolls the ball off the rock, jumps off and grabs the ball on ground but B grabs him by the foot and he loses the ball; she wrestles with him and she gets the ball. (see next section for more re-engagement attempts.)

Ending the game: The game seems to end when B is distracted by another female, Zura. Z pokes at B (46.25) and B runs after her. S takes the ball and makes unsuccessful attempts to re-engage B with the ball game: S carries the ball with him down to the other end of the yard where B is and eventually (49.54) does a running display in front of her carrying the ball in one hand and dragging a branch with the other (RE), then stops and sits looking at her as she approaches, holding the ball and moving gaze twice from her to the ball (GA 50.04). As she gets close to him, he places a hand on top of the ball jiggling it slightly, still looking at her (GG 50.03), and as she comes right next to him, he removes his hand and lets the ball move slightly toward her, practically offering it to her (HO 50.07). She is still distracted and when she goes on past him, he immediately gets up and leaves the ball. A little later, B passes near S again; he lies on his back near Pogo with the ball held in feet, GA 51.40. When she passes by, again ignoring him, he claps both hands audibly on the ball and runs toward her holding the ball, rolling the ball ahead of him as he passes her (OA, RE 51.53). A moment later, they can be seen wrestling, with the ball on ground nearby. The camera leaves B and S but the ball can be heard bouncing on the rocks and can be seen there a moment later as S and B wrestle nearby. At this time, Zura retrieves the ball, ending S and B’s interaction with it.

Indications that game focuses on a particular object: S lets the ball go and wrestles with B. They stop a moment, he seems to push her back, then runs to grab for the ball again. He has a hand on it for a brief moment but B takes it and they wrestle some more; during wrestling S reaches out and touches the ball a few times. When B uses both arms to wrestle, she keeps the ball between her feet.

Game 4: 2/25/94

Excerpts from a 14-min episode. Starts 52.50, ends 1.07.13 on DVD. Kubie (K), male, age 18; Shango (S), male, aged nearly 5.

Theme of game: (JA) Kubie: to retain possession of a piece of leather, Shango to grab it.

Starting the game: S runs up and grabs at K’s leather, 52.51. K pulls it away, S runs and hits at K’s hands and sits on the leather. K drags it away though S remains crouched on it for a moment, then K moves it away and stands on it himself.

Maintaining engagement: After K sits for a while, S runs at him with a branch, hits him with the branch then with his hands. K moves the branch, ignores S and continues to sit. S looks at the leather, then up at K (GA 53.32). When S stretches out his hand and pats the ground (GG 53.35), K runs away with leather, spreads it flat in drainage ditch, stands on it and fends off S’s charge. S sits down nearby, both eat something in ditch for a moment, then K suddenly runs with the leather, looking back at S (GA 54.22). S chases, making several grabs at leather, K fends him off, finally stops by trees and sits on the leather, spreads it out flat, continues to push away approaches by S for several minutes. Finally, K gives him a shove away, grabs the leather and runs to a table-like rock, pursued by S. K lies on the leather and again fends off grappling by S. When K leaves the leather on rock momentarily to pursue S, S makes an end run behind him and almost pulls the leather away (57.07) but K snatches it from him. Similar activity around a leather “base” continues for duration of episode. When Kubie leaves the leather for a moment, he alternates his gaze between S and the leather, 3 times (GA 1.00.53, 1.00.56, 1.01.01). At 1.01.02 S briefly gets possession of the leather piece, but K takes it back within seconds.

Re-engaging after pauses in game: (RE) The pauses are with the two gorillas in very close proximity and often gazing face to face; there is never a real interruption where one tries to leave the game. After moments of pause where K simply stands or sits on the leather, either S runs at K or K runs off holding the leather, thus encouraging more play (RE). Toward end of game, K takes the leather to the top of rock formation, and there is a substantial pause when S stays below. But he eventually climbs up, reaches up from below and slaps the leather K is sitting on (1.06.04).

Ending the game: Precise ending of game is not known because the camera quits at 1.07.13, but this is where K returns to the exact spot where game started, and we see S run away from the area.

Indications that game focuses on a particular object: In spite of K’s keeping close possession of the leather most all of the time, S is continually grabbing at it. S wrestles and chases K but whenever possible seizes the leather. Whenever K moves, he keeps the leather with him. The few times he leaves it, S attempts to run straight to leather and touch it. (JA)

Game 5: 3/18/94

Excerpts from 8-min episode. Starts 1.07.14, ends 1.15.09 on DVD. Zura (Z), female, age 12; Shango (S), male, age 5.

Theme of game: (JA) To possess a ball, sitting or standing on it.

Starting the game: Game grows out of individual play with large and small balls. Shango throws 2 small balls together in front of Zura (OA 1.07.40). Z stands on the large ball and chestbeats and beats on it (1.07.53), but there is no response from S. After S uses the large ball as a seat and beats on it (1.08.45), Z runs in, and S jumps off ball when he sees her coming. He rolls a smaller ball away and plays with it. Then the larger ball becomes a mutual focus for both S and Z.

Maintaining engagement: Z sits on ball, beats on it (GG, 1.10.03) as S makes a twirling approach, jumps off when he gets near. S sits next to ball and beats on it, looks at Z and back to the ball twice (GA 1.10.17) as she moves closer, then S stands on ball and claps with playface as Z sits nearby. She does not react and S starts to roll the ball away. Then Z follows, twirling slowly and armshaking (self-handicapping?), then mildly accelerates to a playful lope (HO 1.10.41) behind S who is rolling the ball ahead of him. Z gets the ball and sits on it. S spins away and gets a smaller ball, stands rolling, drumming, and bouncing it in his hands in front of Z (OA 1.11.16, GA 1.11.19) then squats on a stump, ball held by his feet, his back to Z. Z then stands quadrupedally on a large ball, balancing, and beats on the ball (GG, 1.11.39). S turns and throws his small ball at Z. She chestbeats, cross-armshakes; S claps, they make eye contact and run in circle around large tree in keep-away chase.

Re-engaging after pause in game: (RE) S and Z wrestle and chase, leaving area where the ball is. Watching Z and waiting, at 1.12.18 S returns, running while looking back at Z to beat and sit on large ball (OA 1.12.16, GA 1.12.19). Z comes near and pauses behind a tree, S gets off the large ball and beats on it (OA 1.12.34). With more keep-away and wrestling, both leave the ball again. Z runs off, S goes to the ball and after looking back at Z 2 times (GA 1.13.15) and putting his hand on the ball, he climbs up on it (GG). Both sit a while a little ways apart. At 1.1.3.31(GA) S looks over at Z then slaps her hands (GG, OA 1.13.34) on the ball 10 times. S sits on the ball and slowly slaps its sides, looking at Z. S moves the ball to a tree, keeping his gaze on Z; and as he climbs up on it (1.13.52), Z approaches armshaking. S jumps off the ball and they wrestle. Z throws him off and walks away, S goes to the ball and takes it to the same spot by tree, sits on it again then runs offrolling it, with 2 audible slaps when Z approaches (OA 1.14.37)

Ending the game: The ball rolls away to edge of moat when S and Z wrestle and can be heard rolling off the edge. Kubie runs up and he and Shango play, Zura remains at a distance.

Indications that game focuses on a particular object: actions performed directly upon the ball are frequent in this game, unlike other games where simply holding onto the ball was the point. Examples are beating or slapping on ball, rolling in hands, rolling on ground, bouncing, standing or sitting on a ball. Unlike other games, three balls were objects of play though a large ball was the most prominent. Action upon a ball seemed to be a catalyst for further play action (JA).

Game 6: 6/24/94

Excerpts from a 20-min episode. Starts, 1.15.10, ends 1.35.40 on DVD. Zura (Z), female, age 12; Shango (S), male, age 5.

Theme of game: (JA) To get and keep possession of a particular ball.

Starting the game: Zura picks up the ball, keeping eyes on Shango, who looks back at her. Z throws the ball down a slope into the drainage ditch, looks toward the ball, then S, looks away, then back at S (OA, GA 1.15.20). S’s gaze follows the ball, then he looks at Z, then toward ball, then at Z again (GA). They wrestle for a few seconds before S races ahead of Z into the drainage ditch, turning his head 4 times to watch her pursuit. Z regains the ball down in the ditch.

Maintaining engagement: Z stands still in drainage ditch holding the ball (1.15.59); S rolls down the hill right into her. They wrestle but Z keeps the ball in her hands. When Z lets the ball roll away (1.16.50), S makes a sudden run, grabs the ball and runs off. At the other end of the field, Z regains the ball (1.16.57). After this, there are many interruptions (next section) but the competition for the ball is returned to after each one.

Re-engaging after pauses in game: (RE) S leaves the game 5 times to go sit and/or play with 18-year-old male Kubie, and other interruptions occur when both go indoors, and when Z goes indoors alone.

1.17.54 After S leaves the game to play and sit with Kubie for about 2 min, Z takes the ball to other end of enclosure. S runs toward her, rolling with a branch part of the way. Z moves behind rock structure with the ball; he follows her while she runs, always keeping the ball in one hand.

Z re-engages S when he is sitting with Kubie by running toward S with ball (OA 1.23.45); when he still stays with Kubie, she armshakes with one hand, while the ball is in the other, loping toward S with a slow bipedal gait. She stops again, he continues to play with Kubie. A chestbeat and ball sound can be heard but not on camera. Zura waits, then chestbeats, and slaps stump looking toward S, who is seen to be rapidly approaching (OA 1.24.17, 1.24.40, 1.25.01); they chase but he stops and sits down several feet away; she holds out the ball (OA 1.25.10) while twice alternating her gaze (GA 1.25.15) between the ball and S. Then Shango gives a chase again, regains the ball and throws it into the ditch, where Z takes it. 1.25.36 GA as she looks back 4 times at Shango while running up the hill with the ball.

Zura remains seated when S gets the ball again; S looks back at Z (GA 1.25.54) while walking slowly off with the ball, then obliquely approaches her and alternates gaze 4 times between the ball and Z (GA 1.26.04) as he rolls the ball just ahead of himself; he stops with ball on ground and waits gazing at Zura until she suddenly moves, then Shango quickly throws the ball (OA) ahead of himself into the ditch again and rolls behind it.

S is with Kubie again, Z has retrieved the ball and sits on a nearby rock holding it. She drops it on the ground with an audible bouncing sound, which seems to get S’s attention (OA 1.27.02), then looks back at S (GA 1.27.04) while she moves with ball toward the original game location at a large stump. S approaches; Z keeps looking at him as she simultaneously walks away bipedally, slaps the ball, armshakes, and slaps the ball (GG). They chase around the stump, Z holding the ball. They sit and they wrestle; Z still keeps a hand on the ball. 1.28.57 S goes to sit with K again.

Ending the game: S follows Z behind rock formation, and ball sounds can be heard but not seen. S emerges alone, runs behind rocks one more time, but Z is not visible. After this, he goes to K again and does not return to ball play.

Indications that game focuses on a particular object:

1.16.55 While S is running from Z, dribbling the ball that Z eventually takes possession of, they pass close by two other balls of the same size that either gorilla could have easily reached if the goal was simply to possess a ball. However, they ignore these other balls; focus remains on the particular ball being used in the game (JA).

1.21.25 The game is mutually interrupted when both gorillas go indoors. The ball will not fit through the narrow opening of the sliding door. A gorilla hand is seen reaching through the door holding onto the ball even when the ball is outside and the two gorillas are inside.

1.22.15 Both gorillas abandon the ball for a moment after S dislodges the ball, which was stuck in the door opening. He leaves it; Z is not in view. Z appears and retrieves the ball (1.23.00) after S has moved to the other side of the enclosure.

1.26.08 S leaves the ball on the ground near him. Looking at Z, the moment Z makes a move he suddenly scoops the ball up and throws it ahead of him.

1.27.20 Both gorillas let the ball roll away when they wrestle, but Z retrieves the ball, and both rest close together. There are two additional gentle wrestling bouts where the ball is left momentarily, but Z puts her hand on it when each bout pauses.

1.30.00 Z goes indoors alone leaving the ball outside of the doorway gap. S is playing with Kubie. Z comes out and retrieves the ball (1.33.42). S is seen to be approaching rapidly as Z goes with the ball behind the rocks.

Game 7: 6/2/95

Excerpts from 6-min episode. Starts 1.35.41, ends 1.41.29 on DVD. Kubie (K), male, age 20; Shango (S), male, age 6.

Theme of game: (JA) To keep or get possession of a piece of leather.

Starting the game: After play that includes wrestling, simultaneous chestbeating, and branch display, S stands quadrupedally (1.35.49), stares directly at K, then twice alternates gaze (GA 1.35.57) from K to a leather oval on the ground in front of K. Holding his gaze on K, S sits down and puts hand on (GG, OA 1.36.01) the piece of leather. K looks down at the leather; S sits still with his hand on the leather holding his gaze on K for 2 more seconds. Just when K puts his hand out onto the leather, S snatches it up. Kubie does not react. 1.36.07 GA twice more as Shango appears to watch for a reaction from Kubie.

Maintaining engagement: When K looks away, S spreads the leather out then folds it and puts it in his mouth (1.36.12), head shaking and beating the leather. K joins in with head twirling and hand circling, a little leafy branch in mouth. Both are looking at each other. K stands up bipedally, grabs the leather from S and puts it in his own mouth (1.36.20).

Re-engaging after pauses in game: (RE) Both pause and look out and away from each other (1.36.25). Gazes meet again and K headnods and armshakes with the leather in his mouth (OA 1.36.30), then throws the leather behind him and starts toward S punching fist toward him (away) twice. S backs away, watching, then runs away. K returns to the leather (GA 1.36.38, twice) and sits on it. S approaches again, dragging a branch past K while watching him carefully, then with a playface makes a play attack on K from behind and they wrestle (1.36.50). K stays on the leather, rolling around. (GA 1.37.50, 1.38.30) After more play with chestbeating, clap, jump, twirling, headshaking and branches, they separate. K moves away toward trees and sits, and S goes to K’s leather seat area (GA 1.39.11, 1.39.19), picks up the leather, puts it in his mouth and shakes it, spreads it out, puts in his mouth again and stands bipedally nodding and beating on the leather, (OA 1.39.35) then sits on the leather. K first looks away, then toward S as his display continues. When S stops, he looks toward K twice, and again a few seconds later (GA 1.39.42, 1.39.50). When S starts display again (OA 1.40.00), K approaches at a run and S leaves the play area, taking the leather with him, but drops it a few feet from the play area, meanwhile turning to look at K and back down at the leather several times (GA 1.40.08-1.40.33).

Ending the game: K stands quadrupedally in the play area staring at S, gaze is mutual. S moves closer to K, holding the leather, shakes and bites it, then spreads the leather out (OA, RE 1.40.38) looking fixedly at K (1.40.40) until both look down at the leather (GA 1.40.45), then K reaches out to the leather. S pulls the leather back and K does not attempt to approach further but instead sits back down on another piece of leather. While K is looking (GA 1.41.10), S alternates gaze repeatedly between K and the leather, folds the leather, spreads it out, claps, and jumps ontothe leather (OA, RE 1.41.16). After this, Shango still keeps gaze tightly on K but he makes no response.

Indications that game focuses on a particular object:

There is a second similar sized piece of leather at the “home” play location where K is sitting or standing, but throughout, the gorillas focus only on one particular piece of leather. Near the beginning of the game (1.36.00), sitting near K, S keeps a hand on this piece of leather that is on the ground next to K. K reaches out for it but S is alert and pulls it back quickly. K continues to sit and S keeps the leather right next to him with hand on it. A few seconds later (1.36.20), K stands up bipedally and grabs that leather from S and puts it in his own mouth.