Nyantolo, named for an unfortunate comrade of the scout who discovered them, are essentially mindless creatures of instinct who drift through the brackish currents. From time to time, some stimulus wills them to swim with their heavy flippers, but for the most part nyantolo seem content to ease themselves through the swamps with slow strokes of their tails.

When an organic being steps too near a nyantolo's feeding ground, however, that being is added to the menu. The nyantolo explodes into action then, snapping at prey with its bony break and shovel jaw. Nyantolo himself, a Rodian scout who got too close to the then-unknown creature, had his legs swept out from under him by a flipper before his head was crushed by the thing's strong beak.

Fortunately, the nyantolo species does not appear to be social. One stakes out a feeding ground which others appear to ignore as if it never existed. They appear to have short natural life spans - two to five standard years - and reproduce only once or twice within that time. Observed specimens mate communally; nyantolo have three different genders and all three are needed for reproduction. When the mating sea son ends, the creatures go their separate ways, dispensing a cache of eggs in the mud some three standard weeks later.

Nyantolo excrete a tacky substance across their backs; this substance attracts debris and insects of all kinds, who then become stuck, die, and harden into a hollow carapace. This carapace accumulates over the creature's lifetime, drifting and hardening into odd shapes and chambers. Nyantolo vibrate air into these chambers from breathing vents in their backs; this sounds becomes their mating call when the gathering season approaches. The older the being, the bigger and more intricate the shell; the bigger the shell, the louder the call and the greater the amount of mates summoned by that call. Scouts report that these "songs" become quite eerie; the wailing of dozens of nyantolo at mating time is said to drive some men mad.

Xenobiologists have discovered an attraction gland inside the mouths of some captured specimens (in two of the five known sub-species). This gland secretes an oily fluid that draws small fish from up to 15 meters away. The attracted fish swim into the mouths of the nyantolo. Croator (also native to Wyndigal 2) seem to be especially susceptible to these secretions; dissected nyantolo often have fresh croator remains in their double-chambered bellies. Scouts and castaways are well advised to avoid the nyantolos of Wyndigal 2's temperate swamps.