The Petrophaga navaroni¹is a small bright red rodent of the family Lapivora. It is often mistaken for an insect, being almost devoid of hair, except for thick bristles where its armadillo-like plates join. It has six legs, but is not segmented like an insect, the body flows in one piece from the small pointed tail to the round knobbly nose. Perhaps the most curious thing about this adorable creature is its habit of subsisting on a silicon-based diet. It achieves this with the help of its most prominent feature, large spade-shaped teeth. They are made of hardened diamond and are able to bite through solid rock at an amazing rate. The chunks of rock then travel to the stomach and digested by means of hydrochloric acid. The Petrophaga has a highly efficient metabolism, yet also uses a staggering amount of energy; a fully-grown adult can grind up and digest an amazing 28 kg of rock per day! Most of this is absorbed, but a small portion is expelled as a fine powdery sand. There is no liquid waste; as the rodent does not drink, it must retain all water. Very hard stone is either avoided altogether or simply ground up without being digested if the vein is too large for the rodent to navigate around. It does this by means of two antennae that send out weak radio signals and sense subtle differences in the harmonics of the rock when its density changes.

During the mating season, toward the end of the navaronese year, the male petrophaga search for a partner. To this purpose, they roar at a very low frequency, which is inaudible to human ears but may well cause minor earthquakes. If the male petrophaga has found a female, they go through a complex mating ritual that lasts for two days; then part and may not see each other again. After two months, the female petrophaga gives birth to 3-4 young, which immediately leave their mother and start eating their way through the stone.

The tunnels created by the Petrophaga when it eats also serve as protection. Any predators approaching from the front quickly succumb to the diamond teeth, and it can launch a hard spray of sand to the back to defend itself. When not in a tunnel, it can scuttle very fast on its powerful legs, sensing for a soft spot in the rock to bore into.

The only natural predator of the Petrophaga is the Navaronese Pebblehawk. This small bird nests all along the cliffs and has evolved a long and narrow, but powerful beak with which to pry the small rodent out of its tunnels, sometimes splitting the weakened stone in the process. It resembles a brown and grey hummingbird, and can indeed hover; while hunting, however, it grips the rock with small but powerful claws to gain leverage.

Unfortunately the pebblehawk is a sought-after delicacy among the local populace, usually served roasted on skewers, stuffed with its own eggs and smothered in a curry sauce. Because its numbers are severely decimated by uncontrolled hunting, the pebblehawk is growing ever rarer near large cities. This in turn has lead to a n unchecked population explosion among the Petrophaga. It is believed that their ever-increasing number is a large contributing factor in the rapid erosion of the planet’s surface, which is turning a once-fertile land into an endless desert at an alarming rate.

This is the layman’s version of a report by Dr Tanna and Dr Herriot, as presented to Captain Sharpe of the CSS Mariposa. If you have not been following the Beta RPG, this will make no sense whatsoever.