Cheetah (Acinonyx jubatus)- Data, Pictures & Videos

[Acinonyx sp.]

MAMMALIAN SPECIES 

No. 771, pp. 1--6, 3 figs. Acinonyx jubatus. 

By Paul R. Krausman and Susana M. Morales 

Published 15 July 2005 by the American Society of Mammalogists

DIAGNOSIS. 
Acinonyx jubatus is similar in size (60 captive males, X mass = 40.2 kg; 68 captive females, X mass = 35.0 kg-Cam 1994) to leopards (Panthera pardus) and cougars (Puma concolor--Caro 1994). However, cheetahs cannot be confused with other cats. Each cheetah has a unique arrangement of spots on face and body and a tear strea k extending from the come r of the eye to the upper lip behind canines (Caro 1994; Mivart 1900). Leopards do not have the tear streak and cougars do not have spots or the tear streak.

GENERAL CHARACTERS.
Pelage is pale yellow, gray, or fawn on upper parts (Kitchen er 1991) and is covered with small round black spots set closely together and not arranged in rosettes (Nowak 1999). Underparts are paler, often white. A pronounced lachrymal or tear stripe runs from anterior com er of eye down beside muzzle (Kitchener 1991). Ears are small and round with a black patch on back side (Eaton 1982) but tawny at base and edges. Tail is spotted above and pale below with a white tip. Last one third of tail has a series of black rings (Nowak 1999 ). Coat is coarse and hair is somewhat longer on nape than else where, forming a short mane (Nowak 1999). In young cubs, mane is much more pronounced and extends over head, neck, and back (Nowak 1999). Cubs are covered in a long, woolly, bluish-gray mane that makes them less conspicuous to predators on open savanna (Kitchener 1991 ). Cubs have uniform, gray, long hair with spots visible on underfur. Acinonyx jubatus has a slim body; very long legs; and a small, rounded head with short ears. Pup il of eye is circular when contracted (Lydekker 189 5). Paws are narrow compared with those of other cats (Nowak 1999). Claws are blunt and slightly curved. A. jubatus has weakly retractile claws that have no skin folds to protect them. Skull is vaulted and raised high above muzzle and cranium (Fig. 2). Skull is short and broad with enlarged nasal openings. Nasals are short and broad dorsally, and bony palate extend s well behind molars . Unlike most other members of the Felidae, A. jubatus has very large nasal passages. Bullae are relatively small with strong paroccipital process that jut ventrally (Roberts 1951 ). Average external measurements (in mm) of 10 free-living male (mean :t SD) and 7 female A. jubatus from Serengeti National Park, Tanzania, respectively, are: length of nose to anus, 123.3 :t 60, 135.3 :t 28.2; length of tail, 68.3 :t 2.3, 63 .6 :t 4.9; length of hind foot, 28.0 :t 1.4, 27.1 :t 0.7; body mass (kg), 42.3 :t 5.6, 37.9 :t 4.8 (Caro et al. 1987). Shoulder height ranges from 700 to 900 mm (Nowak 1999). Average cranial measurements with parenthetical sample sizes (in mm) for males and females, respectively, are: width of incisors, 9.9 (6), 9.6 (5); width of incisors plus canines, 26.4 (11), 25.2 (8); width of nasa ls, 15.8 (11), 15.9 (8); width of maxilla, 4 1.2 (11), 39.4 (7); width of zygomatic arch, 60.0 (11), 56.5 (6); bullar length , 2.71 (10), 2.59 (8); bullar width , 1.71 (10), 1.62 (8); depth of skull, 6.86 (10), 6.48 (8); length of upper toothrow, 5.08 (11), 5.03 (7); length of mandible, 12.21 (10), 11.35 (8); and length of lower toothrow, 6.11 (9), 5.98 (8). Depth of skull and length of mandible are significantly larger in males (Wayne et al. 1986).


FOSSIL RECORD. 
Early fossil records of A. jubatus are from the Olduvai I bed, east Africa (northern Tanzania) in the lower Pleistocene fauna fossils (Hopwood 1951). The oldest cheetah fossils are from eastern and southern Africa from 3.5-3.0 X 106 years ago (Turner 1997). Paleoecological records show that cheetahlike cats ranged across Asia, Africa, and North America as recently as 10,000 years ago (Kurten 1968). At least 2 other species of Old World cheetahs might have existed at the same time (Caro 1994). Acinonyx pardinensis (ca. 95 kg) occurred in Eurasia and east and south Africa during the Villafranchian period, 1.9-3.8 X 106 years ago, earlier than suggested by the molecular phylogeny, and a smaller form, A. intermedius, found in the mid-Pleistocene, extended from Europe eastward to China (Caro 1994). A. pardinensis was larger and less cursorial than modern cheetahs and spread throughout the Old World. American cheetah like cats have been assigned to Acinonyx, Felis, and Puma, but a recent cladistic study (Van Valkenburg et al. 1990) places these large, long-limbed cats in the genus Miracinonyx. Two species are recognized: M. inexpectata and M. trumani. M. inexpectata includes a nearly complete skeleton from Hamilton Cave, West Virginia. The proportions were intermediate between extant cheetah and puma but larger with fully retractile claws. M. trumani was described from hundreds of bones from Natural Trap Cave, Wyoming (Adams 1979). The bones were larger but otherwise similar to A. jubatus. Thus, cheetah may have originated in North America and dispersed to Eurasia and Africa (Turner 1997). FOSSIL RECORD. Early fossil records of A. jubatus are from the Olduvai I bed, east Africa (northern Tanzania) in the lower Pleistocene fauna fossils (Hopwood 1951). The oldest cheetah fossils are from eastern and southern Africa from 3.5-3.0 X 106 years ago (Turner 1997). Paleoecological records show that cheetahlike cats ranged across Asia, Africa, and North America as recently as 10,000 years ago (Kurten 1968). At least 2 other species of Old World cheetahs might have existed at the same time (Caro 1994). Acinonyx pardinensis (ca. 95 kg) occurred in Eurasia and east and south Africa during the Villafranchian period, 1.9-3.8 X 106 years ago, earlier than suggested by the molecular phylogeny, and a smaller form, A. intermedius, found in the mid-Pleistocene, extended from Europe eastward to China (Caro 1994). A. pardinensis was larger and less cursorial than modern cheetahs and spread throughout the Old World. American cheetah like cats have been assigned to Acinonyx, Felis, and Puma, but a recent cladistic study (Van Valkenburg et al. 1990) places these large, long-limbed cats in the genus Miracinonyx. Two species are recognized: M. inexpectata and M. trumani. M. inexpectata includes a nearly complete skeleton from Hamilton Cave, West Virginia. The proportions were intermediate between extant cheetah and puma but larger with fully retractile claws. M. trumani was described from hundreds of bones from Natural Trap Cave, Wyoming (Adams 1979). The bones were larger but otherwise similar to A. jubatus. Thus, cheetah may have originated in North America and dispersed to Eurasia and Africa (Turner 1997). 

FORM AND FUNCTION. 
The pelage of A. jubatus insulates the body from temperature changes, whereas the color and pattern of spots conceal cheetahs from prey in the open habitats where it hunts. Cheetahs have a high concentration of nerve cells leading to the optic nerve. The concentrated band of nerve cells is called the visual streak and increases the visual acuity of cheetahs. This allows them to detect prey moving against the horizon in open habitats (Kitchener 1991). Skull is high in proportion to its length (Mivart 1900). Cheetahs have a high proportion of temporalis muscle fibers that pull horizontally. This is offset with short canines and thus, smaller opening of the jaws when a killing bite is delivered (Ewer 1973). Infraorbital canal of cheetahs is extremely small (Mazak 1968; Pocock 1951), and nerves from tactile receptors at bases of vibrissae run through it. Brain is considerably convoluted and corpus albicans is divided into 2 corpora mammillaria (Mivart 1900). Nasals are short. Nasal passages are large with 1 infraorbital foramen on each side (Kitchener 1991; Mivart 1900). Nasal aperture is bounded on either side by roots of upper canines; reduction in the size of the teeth permits the enlarged aperture. Dental formula is i 3/3, c 1/1, p 3/2, m 1/1, total 30 (p2 may be absent in some individuals-Nowak 1999). The small upper molar is visible when skull is in profile. Second premolar (p3) is large and projects downward as much as the carnassial or p4 (Mivart 1900). Cheek teeth are narrow and bladelike for slicing flesh. Canines are small and flattened (Ewer 1973). Whiskers of A. jubatus are fewer compared with those of other cats (Ewer 1973). A cheetah's larynx has divided thyroarytenoid folds with a depression between the rostral and caudal folds and a vocal fold with a sharp edge that does not allow the cheetah to roar (Hast 1989). Respiratory tracts of A. jubatus have a wide cross section, particularly the nasal cavities and connecting passages to pharynx and to trachea. This facilitates movement of air during breathing (Grzimek 1990). Enlargement of these connecting tracts is one of the primary reasons for the pronounced bulging of the skull. The cheetah has a relatively small heart that pumps only a small amount of blood. Hunting by cheetahs involves a high speed chase to run down their prey and a throat bite to suffocate the prey. Wide and large nasal passages help increase the concentration of oxygen in the blood during prey suffocation, allowing the cheetah to regain its breath after capture (Kitchener 1991). The short canines of the cheetah are used to make a throat bite, which occludes the prey's trachea leading to suffocation, essential for dispatching mediumsized prey (Ewer 1973; Kitchener 1991). Cheetahs are digitigrade. Hind limbs are longer than forelimbs. Radius, ulna, tibia, fibula, metacarpals, and metatarsals of lower leg are elongated for increased stride length (Kitchener 1991). Tibia and fibula are firmly bound together with fibrous tissue that allows very little rotation about lower leg (Ewer 1973). Back tends to hang slightly when standing (Kingdon 1977). While running, flexing and straightening of the vertebrae column increases stride length (Hildebrand 1961). Tail is long and used as a counterbalance when turning at high speeds (Kitchener 1991). Cheetahs have a preponderance of fast-twitch fibers in the locomotor muscles (83% of the vastus lateralis and ca. 61% of the gastrocnemius). Locomotor muscles of cheetahs are capable of anerobically based exercise (Williams et al. 1997). Cheetahs use their claws as running spikes to increase their grip while pursuing their prey (Kitchener 1991). Cheetahs have very firm foot pads due to running on firm ground. Ridges, which act like the tread on car tires, run along foot pads (Ewer 1973). 

ONTOGENY AND REPRODUCTION. 
Female A.jubatus are polyestrus and cycle ca. every 12 days (range, 3-27 days) in captivity. Females may be receptive from 1 to 14 days (Caro 1994). Cheetahs are induced ovulators and evidence for seasonal breeding is weak (Caro 1994). Females reproduce at 13-16 months of age (Wrogemann 1975) with an average age of sexual maturity between 21 and 22 months (Kitchener 1991). Copulation frequency for cheetahs is 3-5 times per day (Kitchener 1991). Mean motile sperm per ejaculate (25.3 X 10 6-0'Brien et al. 1985) and circulating testosterone levels are generally lower for male A. jubatus < 5 years of age, although captive males have sired offspring in their 3rd year of life (Caro 1994). A high proportion of spermatozoa have abnormalities (Caro 1994). Gestation is 90-95 days (Caro 1994; Kitchener 1991). Births occurred during January-August in east Africa, November-January in Namibia, and November-March in Zambia (Nowak 1999). From 1969 to 1994 in the Serengeti Plains, Tanzania, females gave birth to their 1st litter at ca. 2.4 years, interbirth interval was 20.1 months, and mean litter size was 2.1 cubs (Kelly et al. 1998). Average longevity of females that survived to independence (i.e., remain with mothers) was 6.2 years. Minimum male longevity was 2.8 years for those born in the study area, but 5.3 years for immigrants (Kelly et al. 1998). Litter size can be up to 8 but 6 young are normally the most that emerge from the lair in the wild (Caro 1994; Caro et al. 1987). Females produced an average of 1.7 young to independence and mean reproductive rates were 0.36 young per year, or 0.17 litters per year at independence in Tanzania (Kelley et al. 1998). At birth, young weigh 250-300 g (Kitchener 1991), but can average 463 g in captivity (Wack et al. 1991). Young remain in a lair (usually in a marsh, tall vegetation, or a rocky outcrop) for ca. 8 weeks and may be carried to new lairs during this period (Laurenson 1993). Young open their eyes after 4-11 days and begin walking after 12- 13 days (Kitchener 1991). Young have a thick covering of long, bluish-gray or smokygray hair that appears on nape, shoulders, and back soon after birth. The function of this seems to be camouflage from predators. Infant hair disappears after ca. 3 months of age but a short mane is retained into adolescence and for longer in some individuals (Caro 1994). Milk or deciduous teeth erupt between 3 and 6 weeks (Broom 1949) and are replaced by permanent teeth at ca. 8 months of age (Caro 1994). Young are weaned at 3-6 months. Young may not separate from their mother until they are 15-17 months old (Caro 1994; Eaton 1974).

GENETICS. 
The 2N = 38. Fifty-five cheetahs from Transvaal and in Namibia had no genetic variation at each of 47 allozyme loci (O'Brien et al. 1983a, 1983b). Electrophoretic studies, reproductivesurveys, experiments using reciprocal skin grafts, and analyses of the major histocompatibility complex also show extreme lack of genetic variability (Caro 1994; Yuhki and O'Brien 1990). Genetic monomorphism results in spermatozoal abnormalities and difficulty with captive breeding (O'Brien et al. 1985, 1987). DNA analyses date the genetic monomorphism to ca. 10,000 years ago (Menotti-Raymond and O'Brien 1993) because of population bottlenecks in the Pleistocene (O'Brien et al. 1987) or to interchange between subpopulations equivalent to panmictic breeding (Caro 1994; O'Brien et al. 1987). Consequences of reduced genetic variability may be increased juvenile mortality and susceptibility to disease. However, increased mortality of young would not be expected in species purged of deleterious recessives (Caro 1994). 

CONSERVATION STATUS. 
The International Union for Conservation of Nature and Natural Resources classifies the cheetah as vulnerable and the Asiatic subspecies (A. j. venaticus) as endangered. The entire species is listed as endangered by the United States Department of the Interior, Fish and Wildlife Service, and is on appendix 1 of the Convention of International Trade in Endangered Species (CITES 1982).


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