The Tualapi are the only known enemies of the Mulefa, destroying the Mulefas' villages and causing the loss of many seed-pods. They are described as large, white birds whose wings look like ship sails from a distance. Tualapi are almost always seen in groups. Father Gomez, a human from Lyra's world who entered the Mulefa world was able to repulse a Tualapi attack after killing one of them with his rifle.
The Mulefa have no defence against Tualapi; retreating inland during attacks. Tualapi attacks generally result in total destruction of Mulefa habitats and can cost the Mulefa greatly. Like most animals from the universe of Mulefa, their limbs are in a different position than those of our animals, with a single limb (in the Tualapi's case, a wing) at the front; a pair (legs) at the middle; and a single limb (again in the case of Tualapis, a wing) at the back. Although they are similar to birds in some ways, they do not fly. Instead, they use their wings to navigate rivers as sails and rudders, and emerge onto dry land when attacking the Mulefa.
Even though they are wild and destructive, certain details suggest they are more than mere animals. Just after he killed the first Tualapi he met, Father Gomez watches the reaction of the survivors carefully and comes to the conclusion that the creatures know about death, pain and fear, which means they can be controlled and used for greater tasks. Father Gomez somehow manages to get control over the rest of the swarm and starts to use the Tualapi for transport, suggesting he managed to domesticate, or, perhaps more accurately, enslave them.
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