All members of the genus
Capra are
bovids (members of the family Bovidae), and more specifically caprines (subfamily
Caprinae). As such they are
ruminants, meaning they chew the cud, and have four-chambered stomachs which play a vital role in digesting, regurgitating, and redigesting their food. The genus has sometimes been taken to include
Ovis (sheep) and
Ammotragus (
Barbary sheep), but these are usually regarded as distinct genera, leaving
Capra for ibexes. In this smaller genus, some authors have recognized only two species, the markhor on one side and all other forms included in one species on the other side. Today, nine wild species are usually accepted along with the domestic goat: •
West Asian ibex also known as the wild goat (
Capra aegagrus) •
Bezoar ibex (
Capra aegagrus aegagrus) •
Sindh ibex (
Capra aegagrus blythi) •
Domestic goat (
Capra hircus; includes
feral goat; domesticated from
C. aegagrus and sometimes considered a subspecies of it) •
Asian ibex also known as the Siberian ibex (
Capra sibirica) •
Markhor (
Capra falconeri) •
West Caucasian tur (
Capra caucasica) •
East Caucasian tur (
Capra cylindricornis) •
Alpine ibex (
Capra ibex) •
Iberian ibex also known as the Spanish ibex (
Capra pyrenaica) •
Nubian ibex (
Capra nubiana) •
Walia ibex (
Capra walie) The
goats of the genus
Capra have complex systematic relationships, which are still not completely resolved. Recent studies based on
mitochondrial DNA suggest that the Asian ibex and the Nubian ibex represent distinct species, which are not very closely related to the physically similar Alpine ibex. The Alpine ibex forms a group with the Iberian ibex. The West Caucasian tur appears to be more closely related to the wild goat than to the East Caucasian tur. The markhor is relatively little separated from other forms—previously it had been considered to be a separate branch of the genus. The following
cladogram of seven
Capra species is based on 2022 mitochondrial evidence: }} Almost all wild goat species are
allopatric (geographically separated)—the only geographical overlaps are the wild goat (
Capra aegagrus) with the East Caucasian tur (
Capra cylindricornis), and the markhor (
Capra falconeri) with the Asian ibex (
Capra sibirica). In both cases, the overlapping species do not usually interbreed in the wild, but in captivity, all
Capra species can interbreed, producing fertile offspring. File:Goats as weed control.jpg|Goats used for natural weed control File:Boisseau à décor de bouquetins, sloughis et échassiers - Musée du Louvre Antiquités orientales SB 3174 ; AS 12672.jpg|Prehistoric terracotta pottery from
Susa depicting an
ibex, BC File:Ibex in the French Vanoise National Park.JPG|Ibex securely climbing rocky slope File:Capra nubiana, Tierpark Hellabrunn – 03.jpg|Male Nubian ibex File:Caprine heart.jpg|Caprine heart ==Species and subspecies==