Gentonna

Gentonnas fulfill a aquatic vegetation-eating role on Fermi Island, similar to marine iguanas. Like marine iguanas, a Gentonna is good at holding its breath: it can hold its breath for about 10–12 minutes. Gentonnas are most common in colder southern latitudes of their temperate range, where dark grey to black “blackflora” are more dominant. Juveniles tend to sleep near large masses of shed Bonegrove leaves. Gentonnas move by waddling, wading and paddling. They bask on warm sand, rocks, and occasionally abandoned seafaring shrog nests. They live in large groups, with juveniles in the interior of the group.

=Feeding=

In eating Twinkiiros and Twinkorals, it avoids the intense competition for small, tender blackflora (e.g., Sunstalks) in its habitat. Gentonnas forage mainly in the low intertidal zone, though they can forage even deeper or farther from the shore. Rarely, they eat Mangot fruit-leaves that have gotten on the ground.

A Gentonna requires substantial calories to build up blubber, but its metabolism is fairly slow. It can survive without food without any ill effect for three days, drawing upon its blubber for energy, and takes twelve days to starve.

=Physiology=



Gentonnas have tough, leathery skin with a layer of fat underneath. The fat is often an unappetizing greyish color. Older Gentonnas tend to have thicker shoulder-spikes and rougher, somewhat pebbly skin, the former of which reduces their sense of hearing. Unusually for thornbacks, Gentonnas can hear. Its shoulder spikes sit on a primitive tympanic membrane-like structure. The spikes move as vibrations as carried through the air or water, giving it a weak sense of hearing and a sense of wind direction, which gives them some crude warning of poor weather that could send them out to sea. The spikes can also detect eddies in the water, something like that of a sea lion's whiskers, though much less sensitive.

Eggs are laid internally in a non-nourishing pool organ. The young metamorphose from fish-like larvae to reptile-like newborns inside the mother, and are "born" (nudged along by muscular contractions) when about 12–13 cm in size.

Its jaws are fairly weak, but due to its diet of fairly tender vegetation, they don't really need to be strong.

Like their ancestors, they make mating displays using brightly-colored throat patches.

=Predator Interactions=

Like Sayronts, they are most active at dusk and nighttime, helping it avoid Seashrogs and Velocidohves. Shantaks are their chief predators, as they are much faster and also mainly nocturnal. They almost always stay near the water's edge: their predators are slow swimmers, when they have any notable swimming abilities at all. Their thick skulls and blubbery necks grant them some resistance to the skull-cracking swipes of Shanktaks. They are most vulnerable to predators while young and small, with weaker bones and thinner layers of blubber.

Snapjaw Sandcrocks and Stonebeak Phlyers are rarer predators. Snapjaw Sandcrocks attack them up on the dunes of the beach, where they rarely venture. A Gentonna typically does not die from the trauma of being gored by its shoulder-spikes, but instead of blood loss when the predator rips out chunks of its flesh.

Stonebeak Phylers only attack them if they wander onto the Fermi Temperate Coast, such as by boarding pieces of driftwood, "rafts" made by Raft-Building Cone Puffgrass, or abandoned Seashrog nests. Occasionally, Stonebeak Phylers lodge themselves into a Gentonna’s thick, blubbery flesh with its claws and try to bite it to death, only for the Gentonna to flee into the water, drowning the predator that can’t extricate itself in time.

As they are nocturnal and Seashrogs are diurnal, Seashrogs are only a rare predator. As adults are so large and blubbery, they often survive one hit from a shrog spear, and are able to flee into deep water where shrogs find them inconvenient to pursue. Mated pair Seashrogs attacking together are more likely to kill them. The juveniles are especially vulnerable to shrog attacks, and thus are even more strongly nocturnal than the adults.

=Pirate Waxface Interactions=

Pirate Waxfaces do not recognize them as prey, and thus do not harm them. It is fairly common to see Pirate Waxfaces and a small herd of Gentonnas living closely together near an abandoned seafaring shrog nest. Weaned juvenile Pirate Waxfaces may even stand or sit on top of Gentonnas, helping them "see" (echolocate) the environment better. Juvenile Gentonnas who have been pursued by Velocidohves are slower to approach Pirate Waxfaces, due to their vague resemblance to their predators (which prefer targeting the young and small), but lose this fear when Pirate Waxfaces are holding spears, as it drastically changes their perceived shapes. Pirate Waxfaces repeatedly adjusting their grip on their spears with their necks seems to "hypnotize" Gentonnas, but the rapid shape-changes actually just baffle them. Though they sometimes drift out to sea on shrog nests with Pirate Waxfaces, the Pirate Waxfaces don’t defend them from Stonebeak Phylers (who don’t attack Pirate Waxfaces) and may scavenge their bodies afterward.

=Driftwood Islands Populations and Effects=

Their habit of boarding abandoned seafaring shrog dwellings, including ones newly "abandoned" by Pirate Waxfaces slaughtering the inhabitants, has allowed a small population to spread to the Driftwood Islands Temperate Bank. The journeying Gentonnas eat stored Mangot fruit-leaves, Twinkiiros that may be growing on the ship's underside if it is decaying, and Twinkiiro relatives that are free-floating. Their low metabolisms and ability to go several days without food help them survive the trip. Those Gentonnas that end up on the Driftwood Islands tend to be slightly more tolerant of Pirate Waxfaces (which inadvertently "protect" them from any traveling Seashrogs by killing the Seashrogs) and can go without food for slightly longer, though they appear identical to other populations on Fermi. Those on the Driftwood Islands eat a greater proportion of Twinkiiros than Twinkorals.

Gentonnas' habit of living alongside Pirate Waxfaces in seafaring shrog nests has given Pirate Waxfaces more of a food supply. Though Pirate Waxfaces don't recognize them as prey, they eat what's left when other predators, such as Stonebeak Phylers show up and kill a Gentonna. Predators also include Terrorfang Hafgufa newborns, which aren't large or experienced enough to guarantee killing prey 2.5 meters long and consume them underwater: Gentonnas may escape, board the ship, and die of their wounds. Having a steadier food supply on journeys has helped Pirate Waxfaces get to the Driftwood Islands Temperate Bank. However, once there, they are confused by the geography of the small islands and cannot adapt their prey-finding behavior, and so starve to death. The only traces of their arrival are influences on the genes of local population of Gentonnas and a few microbes from their bodies.

Due to the obstacles of large beach-dwelling and submerged trees on Fermi making it difficult for shrog dwellings to drift out to sea, Gentonna colonization of the Driftwood Islands is sporadic. The rare colonization events mean the Driftwood Islands populations' gene pools have slightly different gene frequencies from a lack of mixing with the main population, though the two populations look identical and aren't even subspecies.

The Fermian population is nigh-indistinguishable from other sea-coast subspecies but for more commonly using "shape-changing" behavior to hypnotize Gentonnas. The more common behavior is simply passed on from parent to offspring, like a wolf teaching pups a locally-distinctive hunting technique.