Kanai has nightmares all night. At dawn, Piya approaches him and asks if he'd be willing to help her keep watch for when and where the dolphins are leaving the pool. She'll take the upstream entrance on the Megha, while Fokir and Kanai will take the downstream one in Fokir's boat. Kanai agrees. He feels miles apart from Fokir, especially since Fokir is entirely uninterested in conversation. Around noon, Fokir spots a dolphin, and Kanai takes the opportunity to try to talk to him. He asks if Fokir remembers Nirmal and if he remembers Kusum. Fokir doesn't remember Nirmal, but says he sees his mother's face everywhere. Kanai understands that Moyna loves Fokir because he seems somehow unformed.
The way that Fokir speaks in such simple terms tells Kanai that there's more that Fokir could learn or do—essentially, he sees the lack of more complex language as a signal that Fokir is uneducated and therefore, teachable. However, this does ignore the fact that Fokir communicates in a number of other ways, many of them far more effective, than simple spoken language. He's the character who's the most comfortable in the jungle, and he and Piya communicated very well without language.
Kanai asks Fokir if he'd ever like to visit a city, noticing only after he says it that he used the informal address instead of the formal. Fokir takes no notice but says he has no interest. As he starts to row back to the Megha, Kanai sees mirages in the water of Fokir boarding a plane for Seattle with Piya and feels very unsettled. Suddenly, as the boat passes close to Garjontola, Fokir stands and points to what he says are tiger tracks in the mud. Kanai can't quite make out the tracks, but Fokir says the tiger probably came down to the water to look at them.
When Kanai starts seeing mirages, it again reinforces the power of the natural world to shape how humans interact with it. The tiger tracks that Fokir notices reinforce this again, while the fact that Kanai can't really see them allows Fokir to gain the upper hand in this power play going on between them.
Kanai finds this idea far-fetched, but Fokir says that the tigers tend to like to watch strangers. Kanai is fairly certain that Fokir is playing a game—it's one that he himself plays often when working as a translator, as it's easy to dramatize threats to in turn build up one's importance as a translator. Fokir asks if Kanai wants to know how he knows it was a tiger, and he places Kanai's hand on the back of his neck. Kanai feels goose bumps and jerks away as Fokir asks if Kanai can also feel "the fear." Kanai thinks for a moment and believes that fear is something learned, not an instinct—and he doesn't feel it.
When Kanai doesn't feel "the fear," it suggests that he and Fokir are, in many ways, speaking two very different languages. Essentially, they're both having to translate right now, given that Kanai doesn't believe there's a tiger nearby, and Fokir is in charge of interpreting the natural world. Especially because it makes Kanai feel vulnerable, this reinforces Fokir's connection to the natural world.
Fokir leans forward and suggests they go take a closer look. Kanai reluctantly agrees, and Fokir explains that Kusum always told him that Garjontola is a place to learn to not be afraid. He asks Kanai if he's a "clean man" and says that on Garjontola, Bon Bibi will protect everyone who's good at heart. Kanai feels unsettled but follows Fokir through the mud to the line of tracks. Fokir fetches his machete to head into the mangroves, but Kanai refuses to go. Suddenly, he feels something around his ankle falls face first into the mud. Fokir tries to help him, but Kanai angrily and uncontrollably curses at Fokir.
The text never mentions exactly what Kanai feels around his ankle, which gives the effect that the natural world is coming alive to conspire against him. This again reinforces that humans exist in the Sundarbans at the mercy of the natural world, and their only way of feeling more secure in their existence is to lean on legends like that of Bon Bibi for protection.
Fokir offers Kanai a hand, but Kanai insults him and sends him away. Fokir goes to the boat and leaves Kanai in the mud. Kanai, gripped with fear, thinks of how animals kill people in tide country: crocodiles drown people before eating them, while tigers mercifully kill people instantly. Kanai pulls himself up and wades into the mangroves, trying to get far away from the water. When he breaks through to a clearing, he sinks to his knees. He can't even remember the word "tiger" as he sits there, feeling as though the cat itself isn't as real as the fear in his head. Kanai opens his eyes and sees a tiger sitting across the clearing.
Kanai's belief that his fear is more real than the tiger represents a major turning point in his development, as this shows him that emotional languages and shared emotional experiences are far more effective forms of communication than spoken language. When the tiger does nothing to attack Kanai, it offers some credence to the Bon Bibi legend and supports the ways that the locals move through the natural world with deference and respect.
Slowly, Kanai backs into the mangroves and then crashes back out to the mud. Piya, Fokir, and Horen run to him and haul him into the boat. He babbles about seeing the tiger, though Horen and Fokir insist there isn't one around.
The fact that Fokir and Horen insist that there's no tiger suggests that it may also have been a mirage, but regardless, Kanai's mental break shows clearly that the natural world is far superior to humans.