Strontode

Behavior and Activity
Most commonly nocturnal, though, depending on the season and weather, it can also be active within two hours of sunset and sunrise. It always hides within a burrow, in a den beneath large rocks, or under dense growths of flora during the hotter, sunnier parts of the day. Their populations are somewhat lower in habitats with limited burrows, big rocks, or large flora (e.g., around Balbasario River at time of evolution) making dried-up Strontode corpses relatively more common.

While a pretty dim-witted organism, over millennia of getting impaled and digested by immature Minidaggers (a major “predator” in some regions), they eventually gained the innate habit of avoiding areas with certain red-orange-green or red-orange gradients.

Strontium Use
Strontodes’ biggest difference from their ancestor is their greater use of strontium, hence the name. Strontium crystals radiate out from its stomach and into its main body, something like patterns of tree rings, if examined closely enough. The crystals get bigger the farther away from its stomach it is, with the crystals just below the skin being barely visible without magnification. Though its gelatinous, hydraulic body is mostly water, its many strontium crystals make it somewhat gritty when eaten.

Its skin is slightly thicker, partly because of the tiny strontium crystal reinforcements. It is able to live comfortably in the daytime in drier, hotter environments than its ancestors, although it's still more prone to sunburn and drying out than other organisms. Its skin is now so thick it cannot absorb a significant level of oxygen through its skin, although it can still absorb oxygen from water through the lining of its mouth and vents, in addition to its sac-lungs.

Physiology
Its nerve nets, which radiate out from the outer walls of its stomach, are big and dense enough to be seen with a little staining and a hand lens, especially around its eyes and just behind its hind legs. The nerves around its hind end coordinate breathing. It lacks a brain, although there are small clumps of nerves around its eyes and hind end.

Whenever the Strontode needs extra air, the nerves cause the hind legs and upper hind legs to twitch, slightly distorting the air sacs and causing them to weakly pull in air. It also pulls in air simply by walking.

Strontodes have thirty-five sacs within the back end of their bodies. Many of the sacs are connected to other sacs by tiny sphincters and passages. Ten sacs are used as lungs, and twenty are used to store water. Five of the latter sacs have a special function of suddenly squirting out water into the stomach, helping wash it out of noxious chemicals or debris slightly too big or spiky to be excreted through its vents.

It has poor visual acuity, roughly equivalent to 144p on Terran visual outlets, although it can detect colors well. It has tiny chemical receptors on the interior rim of its mouth that help it “smell”, which helps it navigate towards things too far away for it to see well.

Reproduction & Life Cycle
Like many related species, it reproduces by luring in mates with a special pattern of glowing from the lights near its mouth. They spawn in slow-moving streams and in ponds, leading to tiny (~1 mm), nigh-embryonic, filter-feeding larvae which somewhat resemble its distant ancestor, the Carpotesta luceremundare. The larvae grow quickly. As they grow, they change from filter-feeding to carnivory, and emerge onto land as tiny juveniles at roughly 3 cm.

Diet & Feeding
It has a broad diet, but favors small, tender purpleflora and small, slow-moving Binucleid “worms” and “bugs”. Though it has a large mouth and stomach, it can’t take bites out of things, so for its bigger diet items, it can only eat small, immature specimens.

Its gizzard is packed with strontium-reinforced, tooth-like bumps. These bumps allow it to crunch up harder foods its relatives may be unable to process, such as small chitinous items.

Antipredator Adaptations
It “drinks” by sucking in water directly through its four vents and into some of its water sacs. The odd method is justified by two large, stream-dwelling Lurkroufo species being predators of thirsty juvenile (<4 cm) Strontodes. Should the Lurkroufo try to drag it under and devour it, the Strontode may be able to get away and lose only its tail.

The spots on its body camouflage it by hiding its outline, though it doesn’t protect it much when in plain sight of predators with good color vision. Strontodes are pretty good at regenerating their tails and the tips of their limbs, though the legs tend to have claw deformities afterward. Lacking natural weapons or armor, Strontodes by hiding, camouflage, skittishness making them quick to flee, limited regeneration ability, tendency to live in sparsely-inhabited habitats or sub-habitats, being unpleasantly gritty to eat and, most of all, sheer numbers.

Predators with calcium-based skeletons who eat a lot of Strontodes tend to have high strontium concentrations in their bones. As strontium is heavier than calcium, flying predators that eat a lot of Strontodes may gain mildly heavier bones.

Strontium Usage
With a greater use of strontium in its tissues than its ancestor, it is more dependent on getting enough strontium. The size of the speck-like strontium deposits in Strontodes' bodies differs depending on local strontium concentrations. Indeed, strontium crystal development can vary so much based on mineral availability across habitats as to give the impression of different subspecies. In areas where strontium supplies are especially low, the gizzard-teeth are poorly-developed, limiting their ability to grind up and extract nutrients from the crunchier parts of their diet. There is a slight correlation between areas with low strontium and predation pressure on Strontodes, as the smaller crystals make them less gritty and therefore more pleasant (or less abrasive) to eat.