Skip to main content

Comparative craniometric measurements of two Canid species in Egypt: the Egyptian red fox and the Egyptian Baladi dog

Abstract

The Egyptian red fox (Vulpes vulpes aegyptiaca) and Egyptian Baladi dog (Canis familiaris) are two members of the Family Canidae that are widely distributed in Egypt. The skulls of different Canid species vary greatly in their size and shape; therefore, they can be used as a tool to study the evolution and evolutionary history of these animals. The craniometric measurements are crucial for species identification and determination of the specific sites for nerve blocks. The present study compared the craniometric measurements of the red fox and Baladi dog skulls by measuring 47 parameters on each skull and calculation of 8 indices. The red fox skull had significantly lower values of 41 craniometric measurements (approximately 87% of the measurements done), including skull length, width, and height, cranial length and width, palatal and mandibular length, and dental measurements. In contrast, the red fox had significantly higher values of only 3 measurements (approximately 6% of the measurements done) including the tympanic bulla measurement. While only three skull measurements did not differ significantly between the red fox and dog. Statistics revealed that domestic dog had significantly higher values of foramen magnum and palatine indices, and significantly lower value of nasal index than those of red fox. The present work reported variations in the gross and craniometric measurements of skull between the red fox and dog. The measured cranial parameters of both adult animals provide valuable information that can be used in ecological studies, comparative anatomy, and clinical veterinary sciences.

Peer Review reports

Introduction

Members of Family Canidae are considered the most geographically widespread among different carnivore families. They are found in all parts of the world, except Antarctica, inhabiting different types of habitats including deserts, forests, mountains, coastal areas, and even grassy lands [1,2,3]. During the late Miocene era, the two genera of Vulpes and Canis were evolved from North America and released to corners of the world and then to North Africa [3, 4].

Canids vary in size, the smallest canid is the Fennec fox, (Vulpes zerda), and the largest is the gray wolf, (Canis lupus) [1, 3]. Canids use their carnassials or sectorial teeth (upper fourth premolar and lower first molar teeth), which have a blade-like morphology, to cut and shear the muscles of their preys in a scissor-like mechanism [1, 3, 5].

The Egyptian red fox, (Vulpes vulpes aegyptiaca) (Sonnini, 1816), is a subspecies of the red fox (Vulpes vulpes) native to Egypt and also called the Nile fox, and it is the most common medium-sized carnivore present in Egypt [3, 6, 7]. The Egyptian red fox is a nocturnal animal although sometimes seen during the daytime. It is an omnivorous animal that forage on reptiles, rodents, rabbits, insects, birds, carrion, invertebrates, fishes, and plant materials [2, 3, 6]. It has been reported from nearly all habitats of Egypt [8,9,10].

The domestic dog [11] is a member of Family Canidae, it is widely terrestrial abundant carnivore sharing human beings their environments. The domestic dog has been descended from the gray wolf, it is considered the first domesticated animal by human being during the prehistoric eras [2, 3]. The Egyptian Baladi (Native, local) dog is a ‘street’ dog and is one of the most common dogs in Egypt [12, 13]. The Baladi dogs are mixed breed animals that descended from a mixture of pharaoh hounds, salukis, and Canaan dogs [13, 14] and have mated with other breeds as well. They are omnivores animals, and they can be kept as pets although they can live depending on themselves [13, 15] or as stray dogs living in the streets or rural countryside [13, 14].

Both the red fox and domestic dog have commensal relationships with human beings [16, 17]. They are considered to be the reservoirs for the rabies and canine distemper viruses [2, 18, 19].

Skulls of Canids are important tool that can be used to study the evolution and evolutionary history of these animals especially in the absence of molecular studies [20,21,22,23]. Skull size and shape have been reported as excellent predictors of feeding habits in Canid species [24]. In addition, they can be used as a useful tool for regional anesthesia of the cranial nerves when performing surgical operations in the head region and tooth extraction [25,26,27,28]. Furthermore, canine morphometric measurements have been reported to be helpful tool for calculation of the total intraconal anesthetic volume [29] The phenotypic variation in the red fox skull results from natural selection while that of the domestic dog results from artificial selection or domestication [30]. Several studies have been done to investigate the morphometric measurements of skulls in several Canid species including the red fox, silver fox, corsac fox, golden jackals, Egyptian wolf, dog, lion, and cat [22, 25, 27, 31,32,33,34,35,36,37,38]. These studies revealed that morphometric measurements of the skull are crucial for species identification. It also can be used as a helpful tool in veterinary forensic investigation [39, 40]. To date, however, there is a paucity of comparative craniomorphometric data for Nile fox and Baladi dog. Therefore, the present study aimed to compare the craniometric measurements of the skulls and mandibles of two members of family Canidae in Egypt: the Egyptian red fox and the Baladi dog representing wild and domestic canids, respectively to assess the adaptation of both species to their ecology. In addition, the results of the study will be useful in the comparative anatomy, veterinary forensic investigation, and hence to get valuable information in the clinical veterinary sciences. In addition, the morphometric measurements presented here might be helpful in veterinary clinical sciences, such as performing regional anesthesia of the head region and tooth extraction. The findings presented in the current study could help in the identification of bone remains excavated from archeological sites.

Materials and methods

Ethical approval

All experiments were approved and performed in accordance with the guidelines and regulations of the Animal Ethical Committee for Veterinary Research of the Faculty of Veterinary Medicine, South Valley University, Qena, Egypt (approval number: 19B-07–2021).

Animal samples

The present study was carried out on skulls of 24 adult Egyptian red fox and 24 adult Baladi dogs. The red fox skulls were collected by vendors during from Qalubiya, Monofiya, Behayra, and Alexandria governorates, while the dog’s skulls were collected from Qena governorate. Specimens were collected from non-archaeological sites during the period (April-July 2021). The sex of the specimens was unknown. Skulls were cleaned from tissue remains and debris, and then bleached by using 40% hydrogen peroxide. Age was estimated using the previously reported dental formula [41]. The skulls of both animals were observed by the naked eye. They were photographed using a digital camera.

Craniometric measurements

A total of 47 parameters were measured on each skull (39 in the skull and 8 in the mandible) using a precision measuring digital sliding caliper with 0.01 mm precision. In addition to 8 indices were calculated. The parameters measured were adopted from those reported previously [22, 31, 33, 37]. Skull indices were calculated following the method reported by Andreis et al. [42]. All measurements were recorded in millimeters (mm). The parameters measured and their landmarks were described in Table 1 and illustrated in Figs. 1, 2 and 3. The names of the bones and foramina of the skull were adopted from the Nomina Anatomia Veterinaria [43].

Table 1 Codes, symbols, and definitions of measurements used in the present study
Fig. 1
figure 1

Measurements of the skull of the Egyptian red fox and domestic dog (a, b) dorsal view and (c, d) ventral view showing: 1. Total skull length, 2. Condylobasal skull length, 3. Basal skull length, 4. Basicranial length, 5. Basifacial length, 6. Viscerocranial length, 7. Facial length, 8. Length of nasals, 9. Snout length, 10. Palatal length, 11. Length of tympanic bulla, 12. Greatest width across the mastoid processes, 13. Zygomatic width, 14. Least width of skull, 15. Greater interorbital width, 16. Inter-canthi distance, 17. Maximum palatal width, 18. Minimum palatal width, 19. Width at canine alveoli, 21. Prosthion, 27. Width of the tympanic bulla, 28. The maximum width of the sagittal crest, 37. Incisive foramen length. Scale bar = 1 cm

Fig. 2
figure 2

Measurements of the skull of the Egyptian red fox and domestic dog (a, b) lateral view and (c, d) caudal view showing: 20. Skull height, 22. Distance from foramen magnum to the middle point of frontal bone, 23. Palatal depth behind tooth row, 24. Depth at infraorbital foramen, 25. Width of braincase, 26. Width across acoustic meati, 29. Alveolar length of upper cheek tooth row, 30. Maxillary tooth row, 31. Height of the occipital triangle, 32. Greatest inner height of the orbit, 33. Foramen magnum height, 34. Foramen magnum width, 35. Distance between the infraorbital foramen and the rostral limit of the orbit, 36. Distance between the infraorbital foramen and the alveolus of the upper canine tooth. Scale bar = 1 cm

Fig. 3
figure 3

Measurements of the mandible of the Egyptian red fox and domestic dog (a, b) lateral view and (c, d) medial view showing: 38. Mandible length, 39. Alveolar length of the mandible, 40. Mandibular tooth raw, 41. Alveolar length of lower cheek tooth row, 42. Mandible height, 43. Distance between the mental foramen and the most rostral point of the mandible, 44. Distance between ventral limit of the mandibular foramen to the ventral border of the mandible., 45. Distance between the mandibular foramen to the caudal border of the mandible. Scale bar = 1 cm

Statistical analysis

The obtained data were analyzed using SPSS software, version 21 (IBM SPSS, Chicago, IL, USA). Descriptive statistics (mean, standard deviation (SD), minimum, and maximum values) were calculated for both species. Mann–Whitney U-test was used to compare the measurements of the two species (because the data did not follow a normal distribution). Statistical significance was indicated when p < 0.05. The correlation between the skull indices and their factors was calculated by Pearson’s correlation.

Results

Morphological differences of the skull

Visual inspection of the skull of the red fox and Baladi dog revealed that the red fox skull was smaller, shorter, and narrower, and had lower height than that of the Baladi dog (Fig. 1, 2).

The frontal bone was more protruded dorsally in the dog than in the red fox. The zygomatic processes of the frontal bone were short and projected laterally in the red fox, but they were larger and projected ventrolaterally in the dog. The osseous boundaries of the orbit were incomplete dorsolaterally in both animals. Therefore, the orbit continued with the pterygopalatine fossa ventrally and temporal fossa caudally. The temporal lines in the skull of the red fox extended caudally from the postorbital processes forming a narrow "V" shape with its apex continued caudally forming a low interparietal crest then a less prominent external sagittal crest. In the dog, the temporal lines extended caudally from the postorbital processes as two ridges that formed a wide “V” shape with its apex continued caudally forming a distinct interparietal crest then a prominent external sagittal crest (Fig. 1a, 1b).

Both animals had a prominent nuchal crest. The occipital condyles and paracondylar processes were less developed in the red fox than in the dog. The shape of the foramen magnum was elliptical in the red fox, but it was oval to circular in the dog. The zygomatic processes of the temporal bone projected more laterally in the Baladi dog than in the red fox. The temporal fossa of the red fox appeared smaller than that of the Baladi dog. The zygomatic arch was thin and sharp in the red fox but thick in the Baladi dog (Fig. 2c, 2d).

The palate was narrow rostrally and increased in width caudally to reach its maximum width at the caudal border of the fourth upper premolar teeth in both animals. However, the palate of the red fox appeared narrower and shorter than that of the Baladi dog. The permanent dental formula in both animals was I 3/3, C 1/1, P 4/4, M 2/3 (Fig. 1c, 1d).

The infraorbital foramen in the red fox was smaller and located at the level between the third and fourth upper premolar teeth while in the Baladi dog it was larger and located above the middle of the third upper premolar tooth (Fig. 2a, 2b). Both animals had two mental foramina with the rostral one being larger than the caudal one. The rostral mental foramen was located at the level of the rostral border of the second lower premolar tooth in the red fox while it was located below the middle of the second lower premolar tooth in the Baladi dog. The masseteric fossa in red fox occupies approximately the whole surface of the ramus of the mandible, it extended more towards the ventral border of the mandible than that in the Baladi dog (Fig. 3a, 3b).

Morphological differences of the mandible

The mandible of the red fox was shorter in length and lower in height than that of the Baladi dog. Moreover, the ventral border of the mandible appeared to be more convex in the Baladi dog than that in the red fox. The caudal end of the coronoid process was inclined caudally, and the mandibular notch was deeper in the Baladi dog than that in the red fox (Fig. 3).

Craniometric measurements

The craniometric measurements of the Egyptian red fox and Baladi dog skull were obtained and presented as mean ± SD in Table. 2. The present data showed significantly different values of 44 craniometric measurements out of 47 measurements done between the red fox and Baladi dog. Only three skull measurements (BCL, IFC, and DIF) did not differ significantly between the red fox and Baladi dog.

Table 2 Mean measurements and standard deviation (SD) values of the red fox and dog skulls

The red fox skull had lower values of 42 craniometric measurements than those in the Baladi dog (P < 0.05 in 41 measurements). It was significantly shorter in length, narrower in width, had lower height than that of the Baladi dog. In addition, the red fox skull had a narrower braincase, shorter cranial length, smaller palatal, and a shorter condylobasal length, than those in the skulls of the Baladi dog. Furthermore, the mandible of the red fox was shorter in length and lower in height than that of the Baladi dog. Regarding the dental measurements, the red fox had significantly shorter alveolar length of the upper and lower cheekteeth rows, maxillary, and mandibular teeth rows. In contrast, the tympanic bulla measurement values (TBL and TBW), BCL, IFC, MFCB were higher in the red fox than in the Baladi dog (P < 0.05 in TBL, TBW, and MFCB) (Fig. 3c, 3d).

Eight craniometric indices were calculated for both the red fox and Baladi dog skulls. Statistics revealed significant difference in FMI, NI, FI between the red fox and Baladi dog. Five indices (SI, CI, FI, NI, and BR) were higher in the red fox than in the Baladi dog, whereas only NI was significantly higher in the red fox. Three indices (WI, FMI, and PI) were higher in the Baladi dog than in the red fox, whereas FMI and PI were significantly higher in the Baladi dog (Table. 3).

Table 3 Mean measurements and standard deviation (SD) values of the red fox and domestic dog skull indices

Correlation analysis

Correlation analysis using Pearson’s correlation was done between the 8 skull indices and their factors for both the red fox and Baladi dog, and presented in Table 4. Positive correlations were present between SI and ZW, WI and TSL, CI and WB, FMI and FMH, NI and ZW, and BP and PL in the red fox skull. While positive correlation were present between SI and TSL and ZW, CI and WB, FMI and FMH, and FI and ZW and VCL in the Baladi dog skull, whereas significant positive correlation was present between FI and VCL. Strong negative correlations were present between CI and CL, and PI and PL NI in the red fox and between CI and CL, and NI and NL in the Baladi dog.

Table 4 Correlation analysis of the red fox and domestic dog skull indices and theirs factors

For the infraorbital nerve block, the infraorbital foramen could be located approximately at 3.4—4.0 cm and 2.8—4.2 cm dorsocaudal to the canine alveolus and approximately 1.2—1.7 cm and 2.2—2.9 cm from the rostral limit of the orbit in the red fox and Baladi dog skulls, respectively. For the mandibular alveolar nerve block, the needle should be inserted approximately at 1.9—2.7 cm and 0.5—0.8 cm from the caudal and ventral borders of the mandible, respectively in the red fox, and approximately 1.6—2.2 cm and 1.0 -1.3 cm from the caudal and ventral borders of the mandible, respectively in the Baladi dog. For the mental nerve block, the mental foramen could be located at approximately 1.7—2.3 cm and 2.8—3.2 cm caudal to the mandibular incisors in the red fox and Baladi dog, respectively.

Discussion

The skulls of mammals are very important and have an adaptive structure, so scientists use them as a good tool for classification, biogeography, and phylogeny [20, 22, 44, 45]. Among mammals, the skull of Canids varies greatly in size and shape. Therefore, craniometric measurements are crucial in characterization of specific breeds and crosses [46]. The present study has compared the craniometric measurements of the skull of two members of family Canidae that are widely distributed in all regions of Egypt: The Egyptian red fox and the Egyptian Baladi dog for the first time.

The current study revealed several variations between the skull of the red fox and Baladi dog. The same observation has previously been reported previously [47]; the Baladi dog skull has larger and more rounded cranium. This result suggests that the Baladi dog had a larger brain than that of the red fox. It has been reported that mammalian species with larger brains, relative to their body mass, show more successful adaptation when introduced to novel or altered environmental conditions than those with smaller brains [48]. The shape of the foramen magnum also varied between the red fox and Baladi dog being elliptical in the red fox and oval to circular in the Baladi dog. In this regard, the foramen magnum is oval in shape in the red fox and raccoon dog [40, 49]. Four shapes of the foramen magnum in dogs have been reported; oval, rhomboid, pentagonal, and circular [50].

In consistence to the present result, the widest part of the red fox palate is located at the level of the caudal border of the upper fourth premolars [51]. In contrast, the widest part of the palate is located at the level of the first molar tooth in Ghanaian dog [52]. Similar to the current findings, the permanent dental formula of the red fox, Baladi dog, and Iberian wolf is I 3/3, C 1/1, P 4/4, M 2/3 [53,54,55]. Although the red fox and Baladi dog are classified as carnivores, they consume omnivorous diet [2, 3, 6, 15].

It is essential for practitioner to know the anatomic position and relationship of the infraorbital and mental nerves when performing nerve block [56]. The infraorbital foramen in the Baladi dog was located slightly rostral to that of the red fox. While the mental foramen in the red fox was located slightly rostral to that the Baladi dog. The distance between the infraorbital foramen and the alveolus of the upper canine tooth was the same in both the Baladi dog in the present study and the Iranian mixed breed dogs [27]. In agreement with the present results, the ventral limit of the infraorbital foramen is located above the level between the 3rd and 4th premolars in the Nigerian local dogs [28]. In contrast, the infraorbital foramen of the dog can be palpated dorsal to the caudal root of the upper 3rd premolar tooth while the mental foramen can be palpated ventral to the rostral root of the second premolar [56]. The later authors added that slight variation in the location of the infraorbital and mental foramina depends on the species, breed, and size of animal. Two mental foramina have been reported in the red fox and corsac fox [35, 55, 57], while one foramen is present in the arctic fox [57].

In the present study, significant differences in the craniometric and dental measurements (44/47, approximately 94% of the measurements done) were demonstrated between the red fox and Baladi dog. The Baladi dog had significantly higher values of approximately 87% of the measurements done (41/47), whereas red fox had significantly higher values of approximately 6% of the measurements done (3/47). The Baladi dog’s skulls were significantly longer, wider, higher than that of the red fox. Variations in craniometric measurements lead to the significant differences in the craniometric indices, which subsequently indicated by variation in skull shape [58]. The facial part of the skull of the Baladi dog was longer and wider than that of the red fox suggesting longer and wider nasal and oral cavities in the Baladi dog than in the red fox.

In agreement to the present findings, the skull, facial, palatal indices are significantly higher in the raccoon dogs compared to those of the red foxes [59]. The values of skull length, skull height, width of the braincase, zygomatic width of the Egyptian red fox were nearly similar to those reported in the red foxes in Hokkaido, Japan [22], Portugal [32], and Mongolia [35]. But they are smaller than those reported in the golden Jackals in Bulgaria [38] and larger than those reported in the corsac fox in Mongolia [35]. Furthermore, the skull and palatal index values of the red fox in the present study are similar to those reported in the red fox in Turkey [37]. Variation in the craniometric measurements of the red fox in different geographical areas is due to the difference in geographical conditions which affect the diet and food resources of the animal [22, 60].

The craniometric measurements of the skulls of the Baladi dog collected from upper Egypt in the present study differed from that reported previously in the domestic dog collected from lower Egypt [33] being shorter in skull and facial length, but longer in cranial length, and the same skull width. The present results showed that the skull index of the Baladi dogs ranged from 50.69 – 52.86 indicating that they belong to the mesocephalic type [61]. In addition, the skulls of the Baladi dog in the current study had higher values of skull length, width, palatine length, and mandibular length than those of the local Nigerian dogs [62] and local Ghanaian dogs [52], but had lower values of skull length, width, and height, and cranial, facial, and palatine length than that reported in the adult male Kangal dogs [34]. Moreover, the Baladi dog in the present study had higher values of skull length and nasal length but lower values of cranial length and cranial width than those reported in the Iranian mixed breed dogs [27]. Moreover, the skull, cranial, facial, and foramen magnum index values of Baladi dog were lower than those of the Aksaray Malakli dog, a local breed of dog in Turkey, while the Baladi dog had higher value for the palatal index [63]. Variations in skull morphometry could be referred to several reasons including variations in the diet, adaptation to local environment, the availability of food, and climatic changes [64]. It is worth mentioning that the Baladi dog in the current study had lower values of skull, facial, and palatal length and zygomatic width than those reported in wolves [65].

The tympanic bullae were larger in the red fox than those in the Baladi dog. This is parallel with previous reports indicating that the red fox has better low-frequency hearing sensitivity than the domestic dog and cat [66, 67] due to doubled tympanic bulla volume during early adulthood in the red fox [67].

The size of temporalis muscle in carnivores is correlated with the width of the temporal fossa [68] and size of the braincase, a large braincase gives more space for a larger and longer temporalis muscle [69]. In this regard, the red fox had a significantly smaller temporal fossa width (55.30 ± 4.36 Vs. 63.38 ± 6.00, P < 0.05) and braincase width (45.39 ± 2.30 Vs.54.61 ± 1.97, P < 0.05) than those of the Baladi dog. These results indicates that the red fox had a significantly smaller temporalis muscle and subsequently smaller masticatory ability than the Baladi dog [22]. In addition, the external sagittal crest of the red fox was less developed while that of the Baladi dog was prominent. In harmony with the current results, the external sagittal crest is more pronounced in the raccoon dog than in the red fox [40]. Projection of the external sagittal crest is associated with strong masticatory muscles [52], including the temporalis muscle [46], and indicates a higher biting force [21]. The raw muscle masses and the physiological cross-sectional area of the masseter, temporalis, and pterygoid muscles are more variable in the dog than in the fox [47]. It is worth mentioning that the dog had longer palate and mandible compared to those in the red fox. The difference in the shape of skull and mandible affects the cross-sectional area of the masticatory muscles and hence the biting force [70]. Relatively longer jaws indicate harder bite force [47]. In addition, there is a strong correlation between bite force and body size as measured by body weight, skull length and skull width [71]. Taken together, these findings suggest that the Baladi dog has more powerful biting force and stronger jaws with powerful mastication process than those of the red fox.

Conclusion

In conclusion, the present study revealed variations in the gross and craniometric measurements of skull between the two different Canid species in Egypt: The Egyptian red fox and the Baladi dog for the first time. These morphological variations reflect their adaptation to their own lifestyle and foraging habits. The measured craniometric parameters of both adult animals provide valuable information that can be used in ecological and archaeological studies, comparative anatomy, interspecies identification, veterinary forensic investigation, nerve block and surgery of the head region.

Availability of data and materials

Data are available from the corresponding author upon reasonable request.

References

  1. Padilla LR, Hilton CD. Canidae. Fowler’s Zoo and Wild Animal Med. 2015;8(8):457–67.

    Article  Google Scholar 

  2. Fleming PJS, Nolan H, Jackson SM, Ballard G-A, Bengsen A, Brown WY, Meek PD, Mifsud G, Pal SK, Sparkes J. Roles for the Canidae in food webs reviewed: Where do they fit? Food Webs. 2017;12:14–34.

    Article  Google Scholar 

  3. Castelló JR. Canids of the world: Wolves, wild dogs, foxes, jackals, coyotes, and their relatives, vol. 135. Princeton University Press; 2018.

    Book  Google Scholar 

  4. Wang X, Tedford RH. Evolutionary history of canids. In: Jensen P, editor. he behavioural biology of dogs. UK: CABI publishing; 2007. p. 3–20.

    Chapter  Google Scholar 

  5. Wang X, Tedford RH, Valkenburgh BV, Wayne RK. Ancestry. Evolutionary history, molecular systematics, and evolutionary ecology of Canidae. In: Macdonald DW, Sillero-Zubiri C, editors. The biology and conservation of wild canids. Oxford Scholarship Online; 2004. p. 39–54.

    Chapter  Google Scholar 

  6. Basuony M, Gilbert F, Zalat S. Mammals of Egypt: atlas, red data listing and conservation. Alexandrina, Cairo: Ministry of State for Environmental Affairs; 2010.

    Google Scholar 

  7. Ginsberg JR, Macdonald DW. Foxes, wolves, jackals, and dogs: an action plan for the conservation of canids. Switzerland, USA: IUCN- International Union for Conservation of Nature and Natural Resources; 1990.

    Google Scholar 

  8. Osborn DJ, Helmy I. The contemporary land mammals of Egypt (including Sinai). Chicago, USA: Field Museum of Natural History; 1980.

    Google Scholar 

  9. Fathy W. Genus Vulpes in Egypt. The evolution and the phylogenetic history: LAMBERT Academic Publishing; 2011.

    Google Scholar 

  10. Basuony M, Saleh MA, Riad A, Fathy W. Food composition and feeding ecology of the Red Fox Vulpes vulpes (Linnaeus, 1758) in Egypt. Egypt J Biol. 2005;7:96–102.

    Google Scholar 

  11. Linnaeus C. Systema naturae per regna tria naturae :secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, vol. 1. 10th ed. Stockholm, Sweden: Impensis Direct. Laurentii Salvii; 1758.

    Google Scholar 

  12. Elmadawy MA, El-Kassas S, Abdo SE, Nagai A, Bunai Y. Genetic diversity among two common populations of Canis lupus familiaris in Egypt by using mitochondrial DNA HVR1 sequence. Slov Vet Res. 2019;56:75–85.

    Google Scholar 

  13. El Shazly A. An historical ecology of the Baladi dog in Egypt. Sweden: Uppsala University; 2019.

    Google Scholar 

  14. Johnstone G. 6 Ancient dog breeds that originated in Egypt. The Sprucepets.com. 2019. Updated on 06/29/21. https://www.thesprucepets.com/egyptian-dog-breeds-4796829.

  15. Bradshaw JWS. The evolutionary basis for the feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus). J Nutr. 2006;136(7):1927S-1931S.

    CAS  PubMed  Article  Google Scholar 

  16. Ghoshal A, Bhatnagar YV, Mishra C, Suryawanshi K. Response of the red fox to expansion of human habitation in the Trans-Himalayan mountains. Eur J Wildl Res. 2016;62(1):131–6.

    Article  Google Scholar 

  17. Dotson MJ, Hyatt EM. Understanding dog–human companionship. J Bus Res. 2008;61(5):457–66.

    Article  Google Scholar 

  18. El-Tholoth M, El-Beskawy M, Hamed MF. Identification and genetic characterization of rabies virus from Egyptian water buffaloes (Bubalus bubalis) bitten by a fox. Virusdisease. 2015;26(3):141–6.

    PubMed  PubMed Central  Article  Google Scholar 

  19. Nouvellet P, Donnelly CA, De Nardi M, Rhodes CJ, De Benedictis P, Citterio C, Obber F, Lorenzetto M, Pozza MD, Cauchemez S, et al. Rabies and canine distemper virus epidemics in the red fox population of northern Italy (2006–2010). PLoS ONE. 2013;8(4):e61588.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  20. Figueirido B, MacLeod N, Krieger J, De Renzi M, Pérez-Claros JA, Palmqvist P. Constraint and adaptation in the evolution of carnivoran skull shape. Paleobiology. 2011;37(3):490–518.

    Article  Google Scholar 

  21. Parsons KJ, Rigg A, Conith AJ, Kitchener AC, Harris S, Zhu H. Skull morphology diverges between urban and rural populations of red foxes mirroring patterns of domestication and macroevolution. Proceedings Biological sciences. 1928;2020(287):20200763.

    Google Scholar 

  22. Amaike Y, Oishi T, Uraguchi K, Abramov AV, Masuda R. Geographical variation in skull morphology in the Hokkaido population of the red fox (Vulpes vulpes). Mammal Study. 2015;40(4):245–56.

    Article  Google Scholar 

  23. Pitulko VV, Kasparov AK. Archaeological dogs from the Early Holocene Zhokhov site in the Eastern Siberian Arctic. J Archaeol Sci Rep. 2017;13:491–515.

    Google Scholar 

  24. Meloro C, Hudson A, Rook L. Feeding habits of extant and fossil canids as determined by their skull geometry. J Zool. 2015;295(3):178–88.

    Article  Google Scholar 

  25. Saber A, Cacec T, Gummow B, Johns K. Morphometric studies on the skull of the Australian domestic cat (F. catus) and its clinical implications for regional anesthesia. J Vet Anat. 2016;9(1):1–24.

    Article  Google Scholar 

  26. Mohamed R. A descriptive morphometric approach of the skull and mandible of the common opossum (Didelphis Marsupialis Linnaeus, 1758) in the Caribbean and its clinical application during regional anaesthesia. Vet Sci. 2018;5(1):29.

    PubMed Central  Article  Google Scholar 

  27. Monfared A. Anatomical study of the skull of the adult dogs and its clinical value during regional anesthesia. Global Veterinaria. 2013;10(4):459–63.

    Google Scholar 

  28. Igado OO. Rostrofacial indices of the Nigerian local dog: implications in veterinary oral and maxillo-facial anaesthesiology of the dolichocephalic canine breed. Int J Morphol. 2014;32:738–43.

    Article  Google Scholar 

  29. Klaumann PR, Moreno JCD, Montiani-Ferreira F. A morphometric study of the canine skull and periorbita and its implications for regional ocular anesthesia. Vet Ophthalmol. 2018;21(1):19–26.

    CAS  PubMed  Article  Google Scholar 

  30. Driscoll CA, Macdonald DW, Brien SJ. From wild animals to domestic pets, an evolutionary view of domestication. PNAS. 2009;106(Supplement 1):9971.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  31. Younes MI, Fouad FF. Cranial allometry, sexual dimorphism and age structure in sample of the Egyptian wolf canisanthuslupaster. Al-azhar bulletin of science. 2016;27(Issue 1-C):1–8.

    Article  Google Scholar 

  32. Gomes AC, Valente A. Cranial and body size variation in the Iberian red fox (Vulpes vulpes silacea). Mamm Biol. 2016;81(6):638–43.

    Article  Google Scholar 

  33. Saber A, Gummow B. Skull morphometry of the lion (Panthera leo), dog (Canis lupus familiaris) and cat (Felis catus). J Vet Anat. 2015;8(1):13–30.

    Article  Google Scholar 

  34. Onar V, Ozcan S, Pazvant G. Skull typology of adult male Kangal dogs. Anat Histol Embryol. 2001;30(1):41–8.

    CAS  PubMed  Article  Google Scholar 

  35. Munkhzul T, Reading RP, Buuveibaatar B, Murdoch JD. Comparative craniometric measurements of two sympatric species of Vulpes in Ikh Nart Nature Reserve. Mongo J Biol Sci. 2018;16(1):19–28.

    Google Scholar 

  36. Kistner TM, Zink KD, Worthington S, Lieberman DE. Geometric morphometric investigation of craniofacial morphological change in domesticated silver foxes. Sci Rep. 2021;11(1):2582.

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  37. Onar V, Belli O, Owen PR. Morphometric examination of red fox (Vulpes vulpes) from the Van-Yoncatepe Necropolis in Eastern Anatolia. Int J Morphol. 2005;23:253–60.

    Article  Google Scholar 

  38. Stoyanov S. Craniometric differentiation of golden jackals (Canis aureus L., 1758) in Bulgaria. In: International symposium on hunting, modern aspects of sustainable management of game populations. Zemun-Belgrade: Faculty of Agriculture; 2012. p. 39–47.

  39. Donlon D, Croker S, Menzies J. Non-human bones in forensic casework: not such a trivial problem. Forensic Sci Med Pathol. 2020;16(3):442–9.

    PubMed  Article  Google Scholar 

  40. Jurgelėnas E, Daugnora L, Monastyreckienė E, Balčiauskas L. On the skull morphology of raccoon dog (Nyctereutes procyonoides) and red fox (Vulpes vulpes). Acta Zoologica Lituanica. 2007;17(1):41–6.

    Article  Google Scholar 

  41. Singh B. Dyce, Sack, and Wensing’s textbook of veterinary anatomy. 5th ed. St. Louis, Missouri: Saunders/Elsevier; 2018.

    Google Scholar 

  42. Andreis ME, Polito U, Veronesi MC, Faustini M, Di Giancamillo M, Modina SC. Novel contributions in canine craniometry: Anatomic and radiographic measurements in newborn puppies. PLoS ONE. 2018;13(5):e0196959–e0196959.

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  43. World Association of Veterinary Anatomists. Nomina Anatomica Veterinaria. 6th ed. Hanover, Germany: International Committee on Veterinary Gross Anatomical Nomenclature; 2017.

    Google Scholar 

  44. Cardini A, Polly PD. Larger mammals have longer faces because of size-related constraints on skull form. Nat Commun. 2013;4(1):2458.

    PubMed  Article  CAS  Google Scholar 

  45. Usui K, Tokita M. Creating diversity in mammalian facial morphology: a review of potential developmental mechanisms. EvoDevo. 2018;9:15–15.

    PubMed  PubMed Central  Article  Google Scholar 

  46. Evans H, de Lahunta A. Miller’s anatomy of the dog. 4th ed. St. Louis, Missouri: Saunders/Elsevier; 2013.

    Google Scholar 

  47. Brassard C, Merlin M, Monchâtre-Leroy E, Guintard C, Barrat J, Garès H, Larralle A, Triquet R, Houssin C, Callou C, et al. Masticatory system integration in a commensal canid: interrelationships between bones, muscles and bite force in the red fox. J Exp Biol. 2021;224(Pt 5):jeb224394.

    PubMed  Article  Google Scholar 

  48. Sol D, Bacher S, Reader SM, Lefebvre L. Brain size predicts the success of mammal species introduced into novel environments. Am Nat. 2008;172(Suppl 1):S63-71.

    PubMed  Article  Google Scholar 

  49. Hidaka S, Matsumoto M, Hiji H, Ohsako S, Nishinakagawa H. Morphology and morphometry of skulls of raccoon dogs, Nyctereutes procyonoides and badgers, Meles meles. J Vet Med Sci. 1998;60(2):161–7.

    CAS  PubMed  Article  Google Scholar 

  50. Kupczyńska M, Czubaj N, Barszcz K, Sokołowski W, Czopowicz M, Purzyc H, Dzierzęcka M, Kinda W, Kiełbowicz Z. Prevalence of dorsal notch and variations in the foramen magnum shape in dogs of different breeds and morphotypes. Biologia. 2017;72(2):230–7.

    Article  Google Scholar 

  51. Mahdy MAA, Mohammed ESI. Scanning electron microscopy of the palatine mucosa with connective tissue papillae of the Egyptian red fox (Vulpes vulpes aegyptiaca, Linnaeus, 1758). Microsc Res Tech; 2021.

    Book  Google Scholar 

  52. Opoku-Agyemang T, Essel-Cobbinah D, Sia DD, Mukundane-Springs S, Folitse RD, Emikpe BO. The morphometrics and typology of the skull in the Ghanaian local dog of non-descript breed (canis lupus familiaris). Int J Morphol. 2020;38(3):706–13.

    Article  Google Scholar 

  53. Toledo González V, Ortega Ojeda F, Fonseca GM, García-Ruiz C, Navarro Cáceres P, Pérez-Lloret P, MarínGarcía MDP. A morphological and morphometric dental analysis as a forensic tool to identify the Iberian wolf (Canis lupus signatus). Animals. 2020;10(6):975.

    PubMed Central  Article  Google Scholar 

  54. Evans HE, de Lahunta A. Guide to the dissection of the dog. 8th ed. Missouri Saunders/Elsevier: St. Louis; 2017.

    Google Scholar 

  55. Mahdy MAA, Zayed M. Computed tomography and cross-sectional anatomy of the head in the red fox (Vulpes vulpes). Anat Histol Embryol. 2020;49(6):708–17.

    PubMed  Article  Google Scholar 

  56. Beckman B, Legendre L. Regional nerve blocks for oral surgery in companion animals. Comp Cont Ed Prac Vet. 2002;24(6):439–44.

    Google Scholar 

  57. Frackowiak H, Nabzdyk M, Kulawik M, Przysiecki P, Nowicki S. Comparative craniometry and skull morphology of the red fox (Vulpes vulpes) and the arctic fox (Vulpes lagopus). Nauka Przyroda Technologie. 2013;7(3):42.

    Google Scholar 

  58. Zatoń-Dobrowolska M, Moska M, Mucha A, Wierzbicki H, Dobrowolski M, Plaizier J. Variation in fur farm and wild populations of the red fox, Vulpes vulpes (Carnivora: Canidae) — Part II: Craniometry. Can J Anim Sci. 2018;98(1):84–97.

    Google Scholar 

  59. Jurgelėnas E, Daugnora L, Lasys V, Venskutonis D. Skull shape variation of raccoon dogs and red foxes in Lithuania. Veterinarija ir Zootechnika. 2011;55(77):8–13.

    Google Scholar 

  60. Englund J. Cranial and skeletal size in red foxes, Vulpes vulpes (Carnivora, Canidae) in areas with large variation in food abundance. Russian J Theriol. 2006;5:25–34.

    Article  Google Scholar 

  61. Bognár Z, Szabó D, Deés A, Kubinyi E. Shorter headed dogs, visually cooperative breeds, younger and playful dogs form eye contact faster with an unfamiliar human. Sci Rep. 2021;11(1):9293.

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  62. Igado OO. Skull typology and morphometrics of the Nigerian local dog (Canis lupus familiaris). Niger J Physiol Sci. 2017;32(2):153–8.

    PubMed  Google Scholar 

  63. İlgün R, Özüdoğru Z, Karabulut O, Can M. Investigation of macroanatomical and morphometric on the skull bones of Aksaray Malakli dogs. Folia Morphol (Warsz). 2021;81(1):157–63.

    Article  Google Scholar 

  64. Griciuvienė L, Paulauskas A, Radzijevskaja J, Gedminas V. Variability of skull morphometric characters in Nycetereutes procyonoides. Biologija. 2013;59(2):151–6.

    Article  Google Scholar 

  65. Andersone Z, Ozolin J. Craniometrical characteristics and dental anomalies in wolves Canis lupus from Latvia. Acta Theriol. 2000;45:549–58.

    Article  Google Scholar 

  66. Malkemper EP, Topinka V, Burda H. A behavioral audiogram of the red fox (Vulpes vulpes). Hear Res. 2015;320:30–7.

    PubMed  Article  Google Scholar 

  67. Malkemper EP, Mason MJ, Burda H. Functional anatomy of the middle and inner ears of the red fox, in comparison to domestic dogs and cats. J Anat. 2020;236(6):980–95.

    PubMed  PubMed Central  Article  Google Scholar 

  68. Radinsky LB. Evolution of skull shape in carnivores: 1. Representative modern carnivores. Biol J Linn Soc Lond. 1981;15(4):369–88.

    Article  Google Scholar 

  69. Damasceno EM, Hingst-Zaher E, Astúa D. Bite force and encephalization in the Canidae (Mammalia: Carnivora). J Zool. 2013;290(4):246–54.

    Article  Google Scholar 

  70. Herring SW. Masticatory muscles and the skull: A comparative perspective. Arch Oral Biol. 2007;52(4):296–9.

    PubMed  Article  Google Scholar 

  71. Ellis JL, Thomason J, Kebreab E, Zubair K, France J. Cranial dimensions and forces of biting in the domestic dog. J Anat. 2009;214(3):362–73.

    PubMed  PubMed Central  Article  Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). No fund received for this study.

Author information

Authors and Affiliations

Authors

Contributions

M. Mahdy: Concept/design; acquisition of data; data analysis/interpretation; drafting of the manuscript; critical revision of the manuscript and approval of the article. W. Mohamed: Concept; acquisition of data; drafting of the manuscript;—review & editing; critical revision of the manuscript and approval of the article. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Mohamed A. A. Mahdy.

Ethics declarations

Competing interests

The authors declare no competing interests.

Ethics approval and consent to participate

The present study was approved by the Animal Ethical Committee for Veterinary Research of the Faculty of Veterinary Medicine, South Valley University, Qena, Egypt (approval number: 19B-07–2021). All experiments were performed in accordance with the guidelines and regulations of the Animal Ethical Committee for Veterinary Research of the Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no conflict of interest.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Mahdy, M.A.A., Mohamed, W.F. Comparative craniometric measurements of two Canid species in Egypt: the Egyptian red fox and the Egyptian Baladi dog. BMC Vet Res 18, 173 (2022). https://doi.org/10.1186/s12917-022-03275-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12917-022-03275-8

Keywords

  • Canidae
  • Dog
  • Craniometric measurements
  • Egypt
  • Red fox
  • Skull