Thorold's deer (Cervus albirostris) is a threatened species of deer found in grassland, shrubland, and forest at high altitudes in the eastern Tibetan Plateau. It is also known as the white-lipped deer (Baichunlu, 白唇鹿, in Simplified Chinese, ཤྭ་བ་མཆུ་དཀར།་ in Standard Tibetan) for the white patches around its muzzle.
This deer fills an ecological niche similar to the Tibetan red deer (shou, the subspecies wallichi of the red deer species group). It was first scientifically described by Nikolai Przhevalsky in 1883. As of early 2011, more than 100 Thorold's deer are kept in Species360-registered zoos, and in 1998 it was estimated that about 7000 remain in the wild.
Although the species was first described by Przhevalsky in 1883, it is also known as "Thorold's deer" because the specimens was procured by G. W. Thorold in 1892 and was described by W. T. Blanford as Cervus thoroldi in 1893. The former genus, however, is named after Przhevalsky (Przewalskium) and the species name (albirostris) comes from the Latin albus (white) and rostrum (snout), referring to the white muzzle and lips. The name also came from the Chinese word baichunlu (白唇鹿, simplified Chinese), meaning "white-lipped". For this reason, Thorold's deer is also commonly known as the white-lipped deer.
Thorold's deer has traditionally been included in the genus Cervus, and genetic evidence suggests this is more appropriate than its erstwhile placement in the monotypic genus Przewalskium.
No subspecies are recognized.
Thorold's deer is one of the largest deer species, with a shoulder height around . Males, which typically weigh from , are significantly larger than females, at in weight. The hair is coarse and grey-brown over most of the body, fading to yellowish buff on the underparts, with a distinct reddish-brown patch on the rump, and a ridge of darker hair running down the spine. During winter, the coat is paler, and about twice as thick as during the summer, being thicker even that of a moose.