Pearback

The pearback is named after the pear-like shape of its hump and tail. Over the course of its evolution, much of its subcutaneous body fat has been relocated to its back, forming a hump. However, its distribution in subcutaneous fat is not quite as isolated as that of a camel, due to conflicting selection pressures. Though having all its subcutaneous fat located in the hump reduces the insulating effect the fat has on its body, thus keeping it cooler in daytime, that same fat distribution causes its limbs to be unprotected from the cold at night. Furthermore, as it is small relative to an adult camel, its greater surface-area-to-volume ratio dissipates more heat to the environment, thus making it too cool at night. This trade-off is especially prominent in the Fermi High Desert, where the nights are even colder.

Its ancestor used its paddles for display, inter-species competition, and defense against predators. Consequently, there was pressure to evolve longer paddles with greater battering ability. As the paddles grew longer, they developed dense knobs at the end, making them similar to medieval maces. This development made them better weapons.

Over time, the paddles became so long that they touched the ground when flapped downwards. The knobs' denseness allowed them to support the organism's weight when used this way. The use of the paddles are "crutches" was manifold: they could see their predators, shantaks, from farther away, lift their bodies away from the hot sand, and allow them to use their forelimbs for other things.

When the proto-pearback used its "crutches" for movement, it had less use for the forelimbs. The legs became too short for walking, and they accumulated mutations in the joints that would have been a tremendous liability if the legs were still used for walking. The joints let the forelimbs curve inward, thus making a primitive "basket." Though the forelimbs were clearly still legs, they were still armlike enough to carry cryobowls. The pearback spends much of its time in the breeding season collecting many species of cryobowls, preferably uncolonized cryobowls, in its forelimbs. After the male goes through the breeding ritual, in this case lifting itself up and down on his crutches, the female makes a brief gesture with one of her crutches. The gesture apparently means "yes, you're good enough", and after this signal the male drops the cryobowls in his forelimbs, the female lays her froglike eggs in the cryobowls, and the male methodically fertilizes them. It is usually the female that picks up the crybowls and keeps the bowls free of competition and predators until the larva mature, but in some populations it is the male that does this.

Due to its hoarding of many species of cryobowls limiting the amount of cryobowls available to other organisms, it has exacerbated the issue of cryobowl reliance among thornback descendants in the places it inhabits. (the shantak, curazzell, durambi and chitjornpecker are not affected.)