When an asteroid struck the Gulf of Mexico at the end of the Cretaceous period, 66 mybth, all dinosaurs other than birds went extinct on all the surface of Earth. With one exception. The dinosaurs that had colonized the far southern continent of Austral-antarctica had spent millions of years adapting to cold, darkness, and scarcity of food, as even in a warm age the six-months-long night of the poles remains a formidable challenge for life.

In later times, Antarctica split off from Australia and settled on the South Pole, while all other continents slowly drifted away. The peculiar fauna and flora of Antarctica, in which we see resemblances with those of Australia and South America, found itself free to evolve in isolation. A few dinosaur species still lingered, along with the ancestors of penguins and primitive whales. This occurred during the warm epochs of Paleocene and Eocene. But being alone at the center of the Southern Ocean had severe consequences.

The belt around 60 degrees of latitude in the Southern Hemisphere was then, as it is now, almost completely devoid of dry land. This allowed formidable winds and an equally formidable sea current to flow unopposed, creating a sharp separation between Antarctica and the rest of Earth. This caused a sharp cooling of Antarctica, and later of the rest of the world, and the first permanent ice started to grow on the South Pole. It was this period of cooling, with the rapid climate changes and contraction of habitats it caused, that drove the ancestors of the 'ikra to develop their intelligence, as the Quaternary Ice Age will do for humans.

But the whole epopee of the 'ikra is but an eyeblink in evolutionary time, and the cooling continues.

According to the historian-philosopher Kyu Taika-Graa'a, there are three natural functions of government, that tend to concentrate into three groups in tension with each other: a Red Order concerned with metaphysics, a White Order concerned with warfare, and a Black Order concerned with economic production. The supremacy of one of these groups upon the others produced the different regimes of Tagra's main powers: in Kru'u, the militaristic White Order rules as the Strategae; in Chaatai, the Black Order takes the form of the Guilds and their Parliament; in Takrakaya, the Red Order is represented by the Divine Empress, acting through the imperial bureaucracy. The different Tayaka and !Akau'a states are not included in her analysis.

• Chaatai Republic
• Takrakaya Empire
• Kru'u Union
• Highland Tayaka
• Lowland Tayaka
• !Akau'a states

See: Comparison between Tagra and Antarctica; Landscapes

Source: (1)

The islands Gudju and 'Ai!u'ai have been produced between the late Paleozoic and the early Mesozoic (300-200 mybth) largely by the subduction of the Pacific plate, much like the Andes, producing elongated mountain ranges with important, and still present, volcanic activity. The rock is mostly volcanic andesite and rhyolite. The region of Kru'u has a similar nature.

The greater part of Tagra is formed by a vast and very stable Precambrian shield, composed by igneous and metamorphic rocks that formed over 3000 mybth. Limestone, sandstone, and shale have formed thick sedimentary layers over this shield in the Palaeozoic and Mesozoic eras. Significant coal deposits have formed all over the continent during the Carboniferous period (350-300 mybth), when it was located on the Equator and covered with swampy forests. Oil and gas deposits are found around the Sea of Storms.

Between these two parts of Tagra there is another rift, slowly growing apart, which has produced the Dragon's Jaw.

Deposits of iron ore have been discovered by human geologists west of the Throat of the Sea. In fact, these are the oxidized remains of Chaatai's industrial cities.

Also see: Wall of the Sea

• Polar Fields: the flat region between the Dragon's Jaw and the Thunder Mountains, including the South Pole; it's perpetually covered in ice.
• Outer islands: the lands of Gudju and 'Ai!u'ai, as well as many smaller islands; the interior is mostly uninhabited, and the coastlines divided between many small queendoms.
• Dragon's Jaw: a jagged mountain range running between the South Pole and the coast of the Sea of Storms, covered in massive glaciers.
• Thunder Mountains: a vast frozen plateau rising between the Polar Fields, Chaatai, and Takrakaya.
• Lightning Mountains: a massive mountain range running along the coastline near the Tayaka lands; it broadens in the southeast, where the Highland Tayaka live.
• Throat of the Sea: a thin wedge of water separating Chaatai from Takrakaya, constantly crossed by ships for either trade or war.
• Sea of Whales: the sea faced by Kru'u and the coastal Tayaka, rich in whales, kelp, and penguins.
• Sea of Storms: the sea extending between Kru'u and the !Akau'a lands, made extremely dangerous for navigation by the catabatic wind and calving icebergs from the Dragon's Jaw.
• Wall of the Sea: the sea current running all around Tagra and separating it from the rest of the planet.

See: Tagran biota

Because of its location centered on the South Pole, the cycle of seasons is somewhat different from what an inhabitant of temperate latitudes might imagine.

Suppose Earth's rotation axis, which defines the Poles, were exactly perpendicular to Earth's plane of orbit around the Sun. In that case, were one to stand on the Equator, they would see the Sun pass exactly overhead at noon every day of the year, rising exactly in the east and setting exactly in the west. Elsewhere, the Sun would reach its peak somewhat to the south (in the Northern Hemisphere) or to the north (in the Southern). The farther away from the Equator were one to be, the lower would the Sun be at noon (and higher at midnight); in any case, there would be 12 hours of daylight and 12 hours of darkness (slightly more sunlight, actually, as darkness occurs only when the Sun is wholly, not partially covered by the horizon). At the Poles, one would see the Sun turning around the horizon, never quite rising or setting.

But in the time of 'ikra as in that of humans, Earth's rotation axis is tilted between 22 and 25° away from the perpendicular to Earth's plane of orbit around the Sun. This tilt means that parts of the Earth point toward the Sun during parts of its orbit. During the northern summer/southern winter, the Northern Hemisphere faces the Sun, whereas the Southern faces away from it; during the southern summer/northern winter, the opposite is true. This means that night and day only last 12 hours each in two days of the year, the equinoxes of spring and autumn – except at the Equator, where a point still spends half of each day in light all year round. Between spring and autumn, in a given hemisphere, days lengthen as a point on the surface enters the sunward region; and between autumn and spring, it is night that lengthens. The maximum length of daylight and night depend from latitude. The days with the longest and shortest daylight are respectively the solstices of summer and winter. There are certain regions, the Polar Circles, which are lit 24 hours/day during the summer solstice (“midnight sun”) and dark 24 hours/day during the winter solstice. As one moves poleward these periods expand, until, at the Poles themselves, 24 h/d daylight lasts half of the year, and 24 h/d darkness the other half.

All of Tagra, except for the northern reaches of 'Ai!u'ai, lies within the Southern Polar Circle; thus perpetual light and darkness are always possible at least some days of the year, though the 6 months/6 months division occurs only at the Pole itself. 'Ikra cultures generally define “summer” as the period in which the Sun never sets, “winter” as that in which it never rises, and “spring” and “autumn” those in which it both sets and rises. The closer one is to the Pole, the longer summer and winter are, and the closer to the horizon the Sun remains at noon and midnight.

Here are the milestone dates for some selected localities within Tagra (the dates remain true for all sites at the same latitude):

Note how the sum of days of the year is 367, rather than 365: this is because days have somewhat lengthened over Earth's history. 31 Jun and 32 Dec are added to the count. The other numeration (1-367) is based on Chaatai's calendar, which fixes day 1 = 23 Jul, the first sunrise of the year. In all cases, 20 Sep and 22 Mar are the dates of the equinoxes.

• 1-7 (23 Lug – 29 Lug): Days of Awakening (from the first appearance of the Sun to the first sunrise completely above the horizon)
• 8-67 (30 Lug – 27 Sep): Krai'ikyu (“Month of Water”, early-mid spring)
• 68-127 (28 Sep – 26 Nov): Krai'ituyu (“Month of Flowers”, late spring & early summer)
• 128-187 (27 Nov – 24 Jan): Krai'ikyaya (“Month of Insects”, mid-late summer)
• 188-247 (25 Jan – 25 Mar): Krai'ichati (“Month of the Sky”, early-mid autumn)
• 248-307 (26 Mar – 24 May): Krai'ichaagri (“Month of the Aurora”, late autumn & early winter)
• 308-367 (25 May – 22 Jul): Krai'ikaadji (“Month of Brooding”, mid-late winter)