Disclaimer: What? Pokemon belongs to Nintendo? Oh darn.
Common Name: Onix, Iwark
Scientific Name: Petraserpens palacolli
Description: Onix is a truly impressive pokemon, an armored serpent measuring 29 feet long and 3½ feet thick in the middle. Dull gray in color, Onix have 11-13 armor plates on their bodies, giving them a segmented appearance. Their eyes are the size of dinner plates, and set deep into a broad, shovel-like head. Males have a large erectable crest on their heads, which when fully raised measures 2½ feet long and otherwise lies flat along the Onix's body. Females have a smaller crest. Onix have dozens of small, conical teeth.
Onix can rear the front of their bodies up to 8 feet in the air.
Range: Onix were once found throughout Johto, Kanto, Hoenn and Sinnoh. Today, they are mainly found in highlands and mountain ranges, such as the Victory Mountains of Sinnoh and Kanto and the Wayward Caves. They are completely extinct in Hoenn. Petraserpens palacolli seviiensis, a dwarf subspecies, are also found on Quest Island in the Sevii archipelago.
Habitat: Onix like any dry, rocky habitat, although they do not like straight deserts. They dislike moisture in the soil, and always burrow above the water table.
Onix will also inhabit manmade tunnels, such as abandoned mines and subway tunnels.
Call: Onix make a deep, honking roar during the mating season and when defending their territory. It is a remarkable sound, and causes most other pokemon to freeze in their tracks. They may also communicate subsonically, rumbling beneath the ground to transmit messages across long distances.
Diet: Onix are ambush predators, waiting beneath the ground and using sensitive vibration sensors in their crests to detect the movement of prey above. They then burst from the ground, raising their upper bodies and snapping up the unfortunate victim.
The favorite prey of Onix are Graveler, which they smash against the ground to crack before eating. They will also eat Machoke, Machamp, Medicham, or most any other pokemon they can swallow. They devour their prey whole, not bothering to tear it up or chew.
Life Cycle: The crashing and roaring of male Onix fighting can be heard from a mile away, as the gargantuan pokemon rear to size each other up, erect their crests, and ram each other with tree-toppling force. These battles determine the edges of their territories, and the rights to all the females within.
Once a male is victorious, the loser must slink off to nurse his wounds, and the victor courts the females within, nuzzling, nudging, and grumbling until they submit. Due to the female's equal size, he rarely uses force, although frustrated young males have been seen taking their emotions out by smashing trees and boulders.
Onix lay 2-4 football sized, oblong eggs, which the female cares for, coiling her body about them. The baby Onix that hatch out are small and light-colored, and usually stay within their parents' tunnels hunting small pokemon until they reach 18 feet in length, at which point they become competitors with their parents and must leave. Females have an easy time of it, settling wherever there is enough prey to support them, but males must battle the dominant male if he wants to settle down. Young male Onix are the ones that venture into marginal habitat such as woodlands, farms, and towns, looking for a place to live. Unfortunately, doing so often gets them in trouble with humans.
Onix are extraordinarily long lived, and may survive for 70 years or more.
Relationship with Humans: Although not as heavily pursued for the battle trade as their relatives the Steelix, Onix are considered by some trainers to be a status symbol, due to their sheer size and wildness.
Onix were once considered pests in dry lowland areas, digging up public works and creating huge pits in the ground. They were thusly exterminated, and today can only be found in the mountains and other uninhabited areas. There is concern that they may be declining due to disturbances from trainers.
Naturalist's Notes: Onix are a vital part of the ecosystem, altering it over vast tracts of their range. They dig immense, multi acre-spanning networks of tunnels, riddling the mountains like wormholes. They are believed to be responsible for the majority of cave systems in Kanto, Johto, Hoenn and Sinnoh, providing not only passage for humans but habitat for multitudes of pokemon species.
Onix dig with their broad, shovel-shaped heads, scooping with their chins and packing the earth down. They inhabit the same tunnels their entire adult lives, and generations of Onix can inhabit the same tunnel system. However, at one time only one male and a handful of females inhabit a territory.
It is believed that Onix navigate within their tunnels using an internal compass, orienting to their home territory even when they are brought into captivity.