Today, the dominant subspecies (S. t. tatarica) only occurs in Kalmykia and Astrakhan Oblast of Russia and in the Ural, Ustyurt and Betpak-Dala regions of Kazakhstan.

[6] Two subspecies are recognised:[6][7][1] In 1945, American paleontologist George Gaylord Simpson classified both in the tribe Saigini under the same subfamily, Caprinae.

[8] In a revision of the phylogeny of the tribe Antilopini on the basis of nuclear and mitochondrial data in 2013, Eva Verena Bärmann (of the University of Cambridge) and colleagues showed that the saiga is sister to the clade formed by the springbok (Antidorcas marsupialis) and the gerenuk (Litocranius walleri).

[13] Fossils excavated from the Buran Kaya III site (Crimea) date back to the transition from Pleistocene to Holocene.

[2] Before the Holocene, the saiga ranged across the mammoth steppe from as far west as modern-day England and France to as far east as northern Siberia, Alaska, and probably Canada.

A 2010 study revealed that a steep decline has occurred in the genetic variability of the saiga since the late Pleistocene-Holocene, probably due to a population bottleneck.

[2][7] Saigas form very large herds that graze in semideserts, steppes, grasslands, and possibly open woodlands, eating several species of plants, including some that are poisonous to other animals.

[26] UK charity RSPB reported in 2022 that, partly due to their conservation efforts, as well as the designation of the Bokey Orda-Ashiozek protected area by the Kazakhstan government, the population had now risen to a peak of 1.32 million.

[28] During the last glacial period, it ranged from the British Isles through Central Asia and the Bering Strait into Alaska and Canada's Yukon and Northwest Territories.

At one point, some conservation groups, such as the World Wildlife Fund, encouraged the hunting of this species, as its horn was presented as an alternative to that of a rhinoceros.

[33] The Mongolian saiga (S. t. mongolica) is found in a small area in western Mongolia around the Sharga and Mankhan Nature Reserves.

Demand for the horns drives poaching and smuggling, which has wiped out the population in China, where the saiga antelope is a class I protected species.

[36] In June 2015, E. J. Milner-Gulland (chair of Saiga Conservation Alliance) said: "Antipoaching needs to be a top priority for the Russian and Kazakh governments.

Saiga horn, known as Cornu Antelopis, is one of the main ingredients in traditional Chinese medicine that is used as an extract or powder additive to the elixirs, ointments, and drinks.

Currently, saiga populations' migratory routes pass five countries and different human-made constructions, such as railways, trenches, mining sites, and pipelines.

[32] Recent trends in climate change have increased the aridity of the steppe region, leading an estimated 14% or more of available pastureland to be considered degraded and useless.

[18] More recent research involving a mass die-off in 2015 indicates warmer weather and attendant humidity led bacteria common in saiga antelopes to move into the bloodstream and cause hemorrhagic septicemia.

[47] Biologist Murat Nurushev suggested that the cause might be acute ruminal tympany, whose symptoms (bloating, mouth foaming, and diarrhea) had been observed in dead saiga antelopes.

[48] According to Nurushev, this disease occurred as a result of foraging on a large amount of easily fermenting plants (alfalfa, clover, sainfoins, and mixed wet, green grass).

[48] In May 2015, the United Nations agency which is involved in saiga conservation efforts issued a statement that the mass die-off had ended.

[49] At a scientific meeting in November 2015 in Tashkent, Uzbekistan, Dr. Richard A. Kock (of the Royal Veterinary College in London) reported that his colleagues and he had narrowed down the possible culprits.

Climate change and stormy spring weather, they said, may have transformed harmless bacteria, carried by the saigas, into lethal pathogens.

[51] Now, scientists and researchers believe the unusually warm and wet uncontrolled environmental variables caused the bacterium to enter the bloodstream and become septic.

[54] Under the auspices of the Convention on the Conservation of Migratory Species of Wild Animals, the Saiga Antelope Memorandum of Understanding was concluded and came into effect on 24 September 2006.