Skulls, Skeletons, Canines & Claws

[Acinonyx sp.]

Cheetah Skull, Bone and Claw morphology data collection 

Skull:
Skull length
Namibia
Namibian farmlands
Male cheetahs in the namibian farmland have a skull length of 23.4 cm (n=54) and females have a skull length of 21.8 cm (n=26). The smallest male had a skull length of 21 cm and largest 26.7 cm.The smallest female had a skull length of 18.5 cm and largest 24.1 cm.(1)


Otjiwarongo
Male cheetahs here had an average skull length of 20.3 cm (n=89) and females 19.1 cm (n=47). The largest male had a skull length of 23 cm and the largest female 21 cm.(3)


Etosha National Park
Male cheetahs here have an average skull length of 15.7 cm (n=298) and female cheetahs have an average skull length of 15.1 cm (n=146).(2)


Total average in Namibia
Male cheetahs had an average skull length of 17.5 cm (n=441) and female cheetahs 16.7 cm (n=191).(1,2,3)


Botswana
Okavango delta 
Male cheetahs in the Okavango delta have 22.7 cm (n=7).(5)


Ghanzi and Kgalagadi District
Male cheetahs in this area have an average skull length of 16.3 cm (n=24) and female cheetahs have an average skull length of 15.6 cm (n=17).(4)


Total average of Botswana
Male cheetahs in Botswana have an average skull length of 17.7 cm (n=31) and females have an average skull length of 15.6 cm (n=17). (4,5)


India
2 female cheetahs in India had an average skull length of 17.5 cm.(6)


Iraq
One asiatic cheetah in Iraq had a skull length of 17.2 cm(7)


Turkestan 
Trans-caspian cheetahs in Turjestan had an average skull length of 16.68 cm for 4 specimens of both genders. (20)


South Africa
Male cheetahs in South Africa had an average skull length of 20.25 cm (n=2).(20)


Other skull lengths
Christiansen et al 2007 gives 14.9 cm for 9 cheetah skulls from museums of unknown genders and ages. Adolffsen et al 2005 gives 17.2 cm for one cheetah skull, gender and age unknown. Cheetah Conservation Botswana 2014-15 gives 15.6 cm for 57 cheetahs of both genders from Serengeti and Masai Mara. Anirudh et al gives a skull length of 15.9 cm. Krausman et al 2005 gives 18 cm for 1 cheetah skull.(5,9,10,19)



Skull width


Namibia
Namibian farmlands
Male cheetahs in the namibian farmlands have an average skull width of 14.6 cm (n=84) and females have an average skull width of 13.3 cm (n=37).The largest male had a skull width of 17.2 cm and the smallest male had a skull width of 12.4 cm.The largest female had a skull width of 14.7 cm and the smallest female had a skull width of 10.8 cm.(1)


Otjiwarongo District
Males in the Otjiwarongo District have an average skull length of 15.88 cm (n=89) and females have an average skull width of 14.93 cm (n=47).The largest male cheetah had a skull width of 18.50 cm and the largest male cheetah had a skull width of 16 cm.(3)


Etosha National Park
Male cheetahs in Etosha national park have an average skull width of 14.1 cm (n=298) and female cheetahs have an average skull width of 13.2 cm (n=146).(2)


Total average in Namibia
Male cheetahs have an average skull width of 14.5 cm (n=470) in all of Namibia and female cheetahs have an average skull width of 13.5 cm (n=230).(1,2,3)


Botswana
Okavango delta
Male cheetahs in the Okavango delta have an average skull width of 15.4 cm (n=7).(5)


Kgalagadi and Ghazni Districts
Male cheetahs in these districts have an average skull width of 14.3 cm (N=24) and female cheetahs have an average skull width of 13 cm (n=17).(4)


Total average in Botswana
Male cheetahs have an average skull width of 14.5 cm (n=31) and female cheetahs have an average skull width of 13 cm (n=17) in all of Botswana.(4,5)


Canine length
Namibian farmlands
Male cheetahs in the namibian farmlands have an average upper canine length of 2.2 cm (n=87) and females have an average upper canine length of 1.6 cm (n=37). Male cheetahs in the namibian farmlands have an average lower canine length of 1.6 cm (n=86) and females 1.4 cm (n=35).The largest male cheetah ever recorded had a upper canine length of 2.6 cm and the smallest cheetah ever recorded had an upper canine length of 1.6 cm in the namibian farmlands.The largest female cheetah had an upper canine length of 2.3 cm and the smallest female cheetah ever recorded had an upper canine length of 1.7 cm in the namibian farmlands.The largest male cheetah ever recorded had a lower canine length of 2.1 cm and the smallest male cheetah had a lower canine length of 1 cm in the namibian farmlands.The largest female cheetah had a lower canine length of 2 cm and the smallest female cheetah had a lower canine length of 1 cm in the namibian farmlands.(1)


Otjiwarongo district
Male cheetahs have an average upper canine length of 2.3 cm (n=89) and female cheetahs have an average upper canine length of 2.2 cm (n=47) in the Otjiwarongo district. Male cheetahs have an average lower canine length of 1.7 cm (n=89) and female cheetahs have an average lower canine length of 1.5 (n=47) in the Otjiwarongo district.The largest male cheetah ever recorded had an upper canine length of 2.6 cm and a lower canine length of 2 cm in the Otjiwarongo district.The largest female cheetah ever recorded had an upper canine length of 2.2 cm and a lower canine length of 1.5 cm in the Otjiwarongo district.(3)


Etosha National Park
Male cheetahs have an average upper canine length of 2.1 cm (n=298) and female cheetahs have an average upper canine length of 2 cm (n=146) in the Etosha National Park. Male cheetahs have an average lower canine length of 1.6 cm (n=298) and female cheetahs have an average lower canine length of 1.4 cm (n=146).(2)


Total average in Namibia
Male cheetahs have an average upper canine length of 2.15 cm (n=474) and lower canine length of 1.6 cm (n=473). Female cheetahs have an average upper canine length of 1.56 cm (n=234) and an average lower canine length of  1.4 cm (n=321).(1,2,3)


Botswana
Kgalagadi and Ghazni districts
Male cheetahs have an average upper canine length of 2.3 cm (n=24) and an average lower canine length of 1.7 cm (n=24) in the Kgalagadi and ghanzi district. Female cheetahs have an average upper canine length of 2.1 cm (n=17)  and an average lower canine length of 1.5 cm (n=17).In the kgalagadi and ghazni districts.(4)


Other canine data
Meachen Samuels reports an average canine ML diameter of 8.82 mm and a canine crown height of 18.63 mm. BVM Anirudh reports a canine length of 30.13 mm and a canine crown height of 14.80 mm. Christiansen reports a upper canine length of 2.8 cm and a lower canine length of 2.08 cm for one cheetah specimen.(15,16)


Other Skull and Skull related Measurements
2 asiatic female cheetahs had a Condylobasal Length of 15.55 cm, Zygomatic width of 11.9 cm, Postorbital width of 5.2 cm, Interorbital width of 3.8 cm, Maxillary width of 4.8 cm, Mandible length of 11.9 cm, skull length-width ratio of 1.44 cm and a Total score of the skull of 29.05 cm. Christiansen reports a cheetah specimen that had a basicranial length of 10.7 cm, snout length of 6.46 cm, Jaw Joint to Carnassial length of 7.47 cm, Jaw Joint to canine length of 10.91 cm, lower jaw length of 12.95 cm and a gape of 6.68 cm. Christensen also reports a cheetah specimen to have a upper canine anteroposterior diameter of 2.82 cm, a upper canine lateromedial diameter of 0.89 cm, a lower canine anteroposterior diameter of 1.05 cm and a lower canine lateromedial diameter of 0.76 cm.Therrien reports a mandibular length of 11.84 cm for cheetahs.One asiatic cheetah from iraq had a condylobasal length of 15.63 cm, zygomatic breadth of 11.41 cm, interorbital breadth of 4 cm, braincase width of 6 cm, canine to molar distance if 5.32 cm and a mandible length of 11.96 cm. A cheetah from El Malfa, Egypt had a zygomatic breadth of 10 cm, canine to molar distance of 4.73 cm and a mandible length of 10.42 cm.In libya 2 female cheetahs had a condylobasal length of 13.44 cm. In Libya 3 female cheetahs had a zygomatic width of 10.06 cm, upper tooth row length of 4.7 cm and a mandible length of 10.28 cm. In Turkestan 4 cheetahs had a condylobasal length of 15.11 cm,  zyomatic width of 11.63 cm and post orbital width of 3.68 cm. In South africa male cheetahs had an average zygomatic width of 13.82 cm (n=2). Furstenburg et al 2011 gives the total score of the skull of 35.58 cm (n=7) and bitemark width of 4.2 cm (6,7,8,10,17,20,22)



Skull structure
Cheetah skulls are highly domed in lateral aspect.The zygomatic arch is broad anteriorly and much narrower posteriorly.The Maxillary process is short and very little salient.The maxillary process does not in anyway overhand the infraorbital foramen.In postorbital processes tare very short and blunt.The vertical branch of the premaxilla protrudes only a short distance between the maxilla and the nasal.The nares are very large.The braincase is very rounded  and there is usually little evidence of a Sagittal crest except at the extreme posterior.Ventrally the palate is short and broadly triangular. The post dental palate has sharp sloping sides.The hamulars are broad hooks.The bullae is inflated but it is relatively small for the overall size of the skull.The mandible is not particularly strongly built.The dentition is distinctive.The cheek teeth are nominally 3.1 / 2.1. The space between the canine and the first premolar is usually narrow.The jaws have little sign of any postcanine gap.The canines exhibit little or no sign of furrowing.The miracinonyx species also have similar skull structure. Cheetah canines are small, hooked backwards and have grooves that are absent or faint. Nasals are Straight to Concave.Anterior facial profile is very steep, skull height is high, Craniofacial angle is strong, choane is very broad, upper canine is short, Basicranial angle is strong, Post orbital construction is weak, Nasal aperture is very broad, Canine furrows are absent, P4 protocone is vestigial, Main cuspid ofp3 is high, Accessory cuspids of p3-p4 is large, Overall size is small, Sagittal crest is small, Infraorbital foramen is strong, P2 is variable, p3 is narrow, p3 relative to p4 is long in cheetah skulls. The upper felseh tooth consists of trenchant blade.(11,12,13,18,20,21)


Size of skull in comparison to the members of the puma lineage
Cheetahs have larger skulls than jaguarundis.There is no significant difference between pumas and cheetahs in the main axis of the skull (length, width,height) and 12 out of 20 skull measurements. Pumas score better in mastoid breadth, temporal fossa length, tooth row length and jaw width. Cheetahs score better in masseteric scar length, post orbital constriction breadth, condyle to length of jaw and orbit to premaxilla length.(14)



Total average
Average skull measurements for both genders
Skull length:17.09 cm (n=757)
Skull width:14.15 cm (n=748)
Upper Canine Length:2.08 cm (n=750)
Lower Canine Length:1.86 cm (n=836)
Condylobasal length:14.89 cm (n=5)
Zygomatic width:11.77 cm (n=9)
Postorbital Width:4.19 cm (n=6)
Interorbital width:3.86 cm (n=3)
Maxillary width:4.8 cm (n=2)
Mandible length:11 cm (n=7)
Skull Length Width Ratio=1.44 (n=2)
Total score of the skull:34.13 cm cm (n=29)
Basicranial length:10.7 cm (n=1)
Snout Length:6.46 cm (n=1)
Gape:6.68 cm(n=1)
Lower Jaw Length:12.95 cm (n=1)
Jaw Joint to Carnassial Length:7.47 cm (n=1)
Jaw Joint to Canine Length:10.91 cm (n=1)
upper canine anteroposterior diameter:2.82 cm (n=1)
 upper canine lateromedial diameter of 0.89 cm (n=1)
lower canine anteroposterior diameter:1.05 cm (n=1)
lower canine lateromedial diameter: 0.76 cm (n=1)
Braincase Width:6 cm (n=1)
Canine to Molar Distance:5.02 cm (n=2)
Upper Tooth Row Length:4.7 cm (n=3)
Bite Mark width: 4.2 cm (n=?)


Bite Force
Wroe et al 2005 gave a BFQ of 119 and a bite force of 472 newtons for a 30 kg cheetah at teh canines. Chritiansen et al 2005 gives canine bite force of 435 newtons and carnassial bite force of 635 newtons for a cheetah with a skull length of 17.17 cm. Christiansen et al 2007 gives a bite force of 339 newtons at the canines, 509 newtons at the carnassials and a BFQ of 73 at the canines and 72 at the carnassials for a 47 kg cheetah. Chritiansen 2007 gives a biteforce of 325 newtons at the canines, 475 newtons at the carnassials and a BFQ of 102 at the canines and 96 at the carnassials for 9 cheetahs with a mean weight of 25 kg.  Cheetahs are exceptional in converting muscular force to biteforce and the distribution of stress while biting. (23,24,25,26,27)


References
1.Morphology, Physical Condition, and Growth of the Cheetah (Acinonyx jubatus jubatus)
2.Regional variation in the cheetah (Acinonyx jubatus) revisited: Morphology of wild and captive populations
3.Africat
4.Regional variation in body size of the cheetah (Acinonyx jubatus) 
5.Cheetah Conservation Botswana 2014-15
6.Fauna of British India
7.The Cheetah (Acinonyx Jubatus 1776) in Egypt (Felidae, Acinonychinae)
8.Libyan Mammals:Cats of Libya
9.Comparative Biteforces and Canine Bending Strength in Feline and Sabertooth felids:implications for predatory ecology
10.Bite Forces, Canine Strength and Skull Allometry in Carnivores
11.Carnivores of West Africa
12.Wild Cats of the World, Sunquist and Sunquist 2002
13.Cranial Morphology of Five Felids
14.Skull morphology and functionality of extant Felidae (Mammalia: Carnivora): A phylogenetic and evolutionary perspective
15.Morphological convergence of the prey-killing arsenal of sabertooth predators
16.Comparing the dimensions of canine tooth in different species
17.Mandibular force profiles of extant carnivorans and implications for the feeding behaviour of extinct predators
18.How old is the cheetah skull shape? The case of Acinonyx pardinensis (Mammalia, Felidae)
19.Acinonyx Jubatus, mammalian species 2005
20.Mammals of the Soviet Union 1988
21.The Royal Natural History 1849-1915
22.Focus on the Cheetah (Acinonyx jubatus)
23.Bite club: Comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa
24.Biteforces Canine Strength and Skull Allometry in Carnivores
25.BITE FORCES AND EVOLUTIONARY ADAPTATIONS TO FEEDING ECOLOGY IN CARNIVORES
26.Comparative bite forces and canine bending strength in feline and sabretooth felids: implications for predatory ecology
27.Allometry in the distribution of material properties and geometry of the felid skull: Why larger species may need to change and how they may achieve it Author links open overlay panel


Bone and Claw:
Introduction
Cheetahs have the proportionally longest bones among felids. The tibia and fibula are bound together allowing little rotation but granting stability while running. The cheetah’s clavicle is joined to the scapula only by ligaments. (1,2,3)



Femur, Ulna, Tibia, Radius and Humerus



Length
Betram and Biewner 1999 reports 4 captive cheetahs having an average humerus length of 22.20 cm, radius length of 22.11 cm, femur length of 25.19 cm, ulna length of 25.27 cm. Nazem and Nakhaei report 5 wild asiatic cheetahs of both genders having an average humerus length of 20.2 cm, radius length of 17.07, ulna length of 21.31 cm. Hudson 2011 reports 3 captive male cheetahs having an average humerus length of 25.93 cm, average radius length of 24.93 cm and 2 captive female cheetahs having an average humerus length of 24.5 cm and an average radius length of 23.2 cm. Hudson 2010 reports 3 captive male cheetahs having a femur length of 28.56 cm, tibia length of 28.96 cm and 2 captive female cheetahs having a femur length of 26.45 cm, tibia length of 27 cm cm. Christiansen 2005 reports 1 cheetah having a femoral length of 25.1 cm, ulna length of 26. 20 cm, humerus length of 22.75 cm and tibia length of 25.0 cm. (1,2,4,5,7)


Diameter and Breadth
Betram and Biewner 1999 reports 4 captive cheetahs having an average humerus AP diameter of 2.2 cm, humerus ML diameter of 1.58, Radius AP diameter of 1.04 cm, Radius ML diameter of 1.64, Femur AP diameter of 1.88 cm, Femur ML diameter of 1.72 cm, Tibia AP diameter of 1.84 cm, Tibia ML diameter of 1.79 cm. Hudson 2010 reports 3 captive male cheetahs having an average femur diameter of 2.25 cm, average tibia diameter of 2.13 cm and captive 2 female cheetahs having an average femur diameter of 2.22 cm, average tibia length of 1.94 cm. Nazam nd Nakhaei 2017 reports 5 wild asiatic cheetahs having an average humerus distal end breadth of 4.21 cm, humerus proximal end width of 3.51 cm, Radius distal end width of 1.82 cm and radius proximal end width of 1.05 cm. Christiansen 2005 reports 1 cheetah having a humerus distal articular width of 2.77 cm, femur distal articular width of 4.26 cm, femur circumference of 5.76 cm, humerus circumference of 5.3 cm, tibia circumference of 5.3 cm, femoral diaphysis anteroposterior diameter of 1.94 cm, humerus diaphysis anteroposterior diameter of 1.78 cm, ulna diaphysis anteroposterior diameter of 0.77 cm, tibia diaphysis anteroposterior diameter of 1.65 cm, femur diaphysis lateromedial diameter of 1.73 cm, humerus diaphysis lateromedial diameter of 1.59 cm, tibia diaphysis lateromedial diameter of 1.71 cm, Humeral head anteroposterior diameter of 2.88 cm, femoral lateral condyle anteroposterior diameter of 2.67 cm, humeral lateral condyle anteroposterior diameter of 1.78 cm, Humeral head lateromedial diameter of 2.98 cm, femoral lateral condyle lateromedial diameter of 1.58 cm, humeral lateral condyle lateromedial diameter of 1.2 cm, femoral medial condyle anteroposterior diameter of 2.43 cm, humeral medial condyle anteroposterior diameter of 2.34 cm, femoral medial condyle lateromedial diameter of 1.34 and humeral medial condyle lateromedial diameter of 1.1 cm. Hudson 2011 reports 3 male cheetahs having an average humerus diameter of 2.02 cm, radius diameter of 1.44 cm and 2 female cheetahs having an average humerus diameter of 2.44 cm, radius diameter of 1.68 cm. (1,2,4,5,7)



Other measurements
5 wild asiatic cheetahs had an average Humerus GLC of 19.66 cm, Humerus SD of 1.17 cm, Radius SD of 0.5 cm, Ulna DPA of 2.46 cm, Ulna SDO of 2.06 cm, Ulna BPC of 1.99 cm. 


GLC=Greatest length from the caput (head) along the axis


SD=Smallest breadth of diaphysis


DPA=Depth across the processus acronaeus


SDO=Smallest depth of the Olecranon


BRC=greatest breadth across the coronoid process


1 cheetah had an Olecranon process length of 3.96 cm.


3 male cheetahs had an average humerus weight of 199 g, radius weight of 77 g, femur weight of 244 g, tibia weight of 181 g and 2 females cheetahs had an average humerus weight of 164 g, 65 g, femur weight of 193 g, tibia weight of 154 g. (1,2,4,5)






Remarks on the bones of asiatic cheetahs


Humerus
The shaft of the humerus is curved cranially and cylindrical. The lateral surface of the humerus is smooth and spiral. The round articular head is strongly curved backwards proximo distally. The round articular head is at the extreme proximal extremity of the caudomedial surface.


Radius
The posterior surface of the radius is concave and showed a non-articular eminence. The lateral surface is rounded and smooth. The medial surface is smooth. The long shaft is flattened cranio caudally. The anterior surface is curved, anterior concave and smooth.


Ulna
The shaft of the ulna is triangular in section and it is slightly convex cranially. The ulna is tapered distally. The medial coronoid process is broad. The lateral process is narrow. The anconeal process projects hook like. The shaft is roughly prismatic. The medial surface is smooth and concave. The proximal end is expanded and comprises one large olecranon process abd a semilunar notch. (5)



Scapula


Measurements
A captive cheetah had a scapula length of 20.3 cm, scapula width of 11.2 cm and a scapular spine length of 18.3 cm. (6)


Remarks on the scapula
The cheetah’s scapula is closer to the resemblance of a canid than a felid. The scapular spine has a reduced and elongated tuberosity. (6)


Muscle morphology
7-8 captive cheetahs had an average hindlimb muscle mass of 3062 g and 3-8 cheetahs had an average forelimb muscle mass of 4031 g. Captive cheetahs have around 50% muscle mass. Cheetah muscles contain a high proportion of the fastest and the most powerful mammalian muscle fibres. A cheetah specimen had a M.Masseter area of 25.84 cm2 and a M.Temporalis area of  38.58 cm2. (1,2,8)


Claw
Cheetahs have canine like claws and they lack fleshy claw sheaths which other species of felids have. All of the cheetah’s claws except the dewclaw are blunt but strong. The dew claw is large, sharp and very curved. (3,9,10)




References:


1.Functional anatomy of the cheetah (Acinonyx jubatus) hindlimb 2010
2.Functional anatomy of the cheetah (Acinonyx jubatus) forelimb 2011
3.Wild Cats of the World
4.Body Size of the Smilodon
5.Anatomy, functional anatomy and morphometrical study of forelimb column in Asiatic cheetah (Acinonyx jubatus venaticus)
6.MORPHOMETRIC BIODIVERSITY IN CHEETAH THORACIC LIMB BONES: A CASE STUDY 
7.Differential Scaling of Limb Bones in Terrestrial Carnivores and Other Mammalia
8.Power output of skinned skeletal muscle fibres from the cheetah (Acinonyx jubatus)
9.Field Guide to Carnivores of the World, 2nd Edition
10.The Wild Cat Book: Everything You Ever Wanted to Know about Cats Reply