Holarctic in the context of Ground squirrel

Omomyidae is a group of early primates that radiated during the Eocene epoch between about 55 to 34 million years ago (mya). Fossil omomyids are found in North America, Europe & Asia, making it one of two groups of Eocene primates with a geographic distribution spanning holarctic continents, the other being the adapids (family Adapidae). Early representatives of the Omomyidae and Adapidae appear suddenly at the beginning of the Eocene (56 mya) in North America, Europe, and Asia, and are the earliest known crown primates.

Omomyids are generally as regarded as closely related to or within the Tarsiiformes, and thus most closely related to tarsiers among living primates.

The Eurasian magpie or common magpie (Pica pica) is a resident breeding bird throughout the northern part of the Eurasian continent. It is one of several birds in the crow family (corvids) designated magpies, and belongs to the Holarctic radiation of "monochrome" magpies. In Europe, "magpie" is used by English speakers as a synonym for the Eurasian magpie: the only other magpie in Europe is the Iberian magpie (Cyanopica cooki), which is limited to the Iberian Peninsula. Despite having a shared name and similar colouration, it is not closely related to the Australian magpie.

The Eurasian magpie is one of the most intelligent birds. The expansion of its nidopallium is approximately the same in its relative size as the brain of chimpanzees, gorillas, orangutans and humans. It is the only non-mammalian species known to pass the mirror test.

The northern pike (Esox lucius), also known as pickerel, jack or simply pike, is a species of carnivorous fish of the genus Esox (pikes). It is commonly found in fresh waters of the Northern Hemisphere (i.e. it has a holarctic distribution).

Pike can grow to a relatively large size. Their average length is about 40–55 cm (16–22 in), with maximum recorded lengths of up to 150 cm (59 in) and maximum weights of 28.4 kg (63 lb). The IGFA currently recognises a 25 kg (55 lb) pike caught by Lothar Louis on Greffern Lake, Germany, on 16 October 1986, as the all-tackle world-record holding northern pike. Northern pike grow to larger sizes in Eurasia than in North America, and in coastal Eurasian regions than inland ones.

Anser is a waterfowl genus that includes the grey geese and the white geese. It belongs to the true goose and swan subfamily of Anserinae under the family of Anatidae. The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern Hemisphere in summer. Some also breed farther south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone between the January 0 °C (32 °F) and 5 °C (41 °F) isotherms.

The genus contains 11 living species.

Erebia is a Holarctic genus of brush-footed butterflies, family Nymphalidae. Most of the about 90–100 species (see also below) are dark brown or black in color, with reddish-brown to orange or more rarely yellowish wing blotches or bands. These usually bear black spots within, which sometimes have white center spots.

This genus has found it easy to adapt to arid and especially cold conditions. Most of its members are associated with high-altitude lands, forest clearings or high latitude and tundra. Erebia species are frequent in the Alps, Rocky Mountains, subarctic and even Arctic regions, and the cooler parts of Central Asia. In fact, the North American term for these butterflies is alpines. Palearctic species are collectively known as ringlets or arguses. However, none of these terms is used exclusively for this genus.

It is widely agreed that the evolutionary lineage of the grey wolf can be traced back 2 million years to the Early Pleistocene species Canis etruscus, and its successor the Middle Pleistocene Canis mosbachensis. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.

The earliest specimens of the modern grey wolf date to around 400,000 years ago, or possibly earlier to 1 million years ago. Most modern wolves share most of their common ancestry within the last 25-23,000 years from earlier Siberian wolf populations. While some sources have suggested that this is the result of a population bottleneck, others suggest that this is a normal consequence of gene flow homogenising wolf genomes across their range.

Saxifraga is the largest genus in the family Saxifragaceae, containing about 473 species of holarctic perennial plants, known as saxifrages or rockfoils. The Latin word saxifraga means literally "stone-breaker", from Latin saxum ("rock" or "stone") + frangere ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi (known as kidney or bladder stones), rather than breaking rocks apart.

The Xyelidae are a comparatively species-poor family of sawflies, comprising about 80 extant species in five genera worldwide, and is the only family in the superfamily Xyeloidea. The fossil record of the family is extensive, comprising more than 120 species and including the oldest fossil Hymenoptera species dating back to the Triassic, between 245 and 208 million years ago. Xyelidae are sister to all other contemporary lineages of Hymenoptera and have many ancestral morphological features.

The extant species occur in the Northern Hemisphere, especially in boreal regions of the Holarctic, though there are a few Oriental species. Two genera and about 15 species occur in Europe. Considering additional fossil records from Australia, South Africa and Argentina, the extant species display a relict distribution. The species in the subfamily Xyelinae are associated with conifers (esp. Pinus and Abies), where the larvae feed on pollen or within buds. The larvae of the subfamily Macroxyelinae feed on the leaves of deciduous trees (various Juglandaceae and Ulmus).

The redpoll (Acanthis flammea) is a species of small passerine bird in the finch family Fringillidae. It is the only species placed in the genus Acanthis. It breeds in the Arctic and north temperate Holarctic tundra and taiga. The redpoll was formerly widely treated as three species: the common or mealy redpoll, the arctic or hoary redpoll (A. hornemanni), and the lesser redpoll (A. cabaret).

Baptornis ("diving bird") is a genus of flightless, aquatic birds from the Late Cretaceous, some 87-80 million years ago (roughly mid-Coniacian to mid-Campanian faunal stages). The fossils of Baptornis advenus, the type species, were discovered in Kansas, which at its time was mostly covered by the Western Interior Seaway, a shallow shelf sea. It is now known to have also occurred in today's Sweden, where the Turgai Strait joined the ancient North Sea; possibly, it occurred in the entire Holarctic.

Othniel Charles Marsh discovered the first fossils of this bird in the 1870s. This was, alongside the Archaeopteryx, one of the first Mesozoic birds to become known to science.

The animals living in Asia and its surrounding seas and islands are considered the fauna of Asia. Since there is no natural biogeographic boundary in the west between Europe and Asia, the term "fauna of Asia" is somewhat elusive but it is a geographical name given. Temperate Asia is the eastern part of the Palearctic realm (which in turn is part of the Holarctic), and its south-eastern part belongs to the Indomalayan realm (previously called the Oriental region). Asia shows a notable diversity of habitats, with significant variations in rainfall, altitude, topography, temperature and geological history, which is reflected in its richness and diversity of animal life.

The genus Fagopyrum is in the flowering plant family Polygonaceae. It includes some important food plants, such as F. esculentum (buckwheat) and F. tataricum (Tartary buckwheat). The genus is native to the Indian subcontinent, much of Indochina, central and southeastern China, and central and eastern tropical Africa. Species have been widely introduced elsewhere, throughout the Holarctic and parts of Africa and South America.