Carnivores
The Order Carnivora descended from a late Palaeocene radiation of mammals, and now there are 13 extant families and 270 species in the Order Carnivora (Myers and Poor, 2007; Vaughan, 2000). Most of these species are carnivorous and primarily eat meat, although some are omnivores, herbivores and insectivores (Feldhamer et al, 2004; Myers and Poor, 2007). Carnivores are distributed worldwide, they occur naturally on all continents (Feldhamer et al, 2004; Myers and Poor, 2007). They occupy all types of terrestrial habitats such as deserts, mountains, forests, grasslands, tundra, open ice and scrublands (Hazard, 1982; Myers and Poor, 2007). The aquatic and semi aquatic species occupy lakes, rivers, marshes, marine coastal areas and the ocean (Hazard, 1982; Myers and Poor, 2007). Carnivores are considered to be very important in many ecosystems, as they control populations of their prey in a ‘top-down’ manner, some are even given keystone species status, the removal of which can devastate an ecosystem (Agee, 1988; Myers and Poor 2007; Ray, 2005).
The defining characteristic of the Order Carnivora is not that they are carnivorous but is actually their morphology (Feldhamer et al, 2004). The defining morphological characteristic is the specialization of their teeth, they possess a carnassial pair (the fourth premolar and the first lower molar) which are used for cutting and shearing (Feldhamer et al, 2004; Myers and Poor, 2007; Vaughan, 2000). The carnassials are especially well developed in the predatory groups such as the felids and the hyaenids (Feldhamer et al, 2004). The canine teeth are conical, well-developed and elongated in the carnivores (Feldhamer et al, 2004; Myers and Poor, 2007). The skulls of carnivores tend to be heavy and vary in size but are distinguishable by having a large braincase and a strong zygomatic arch (Feldhamer et al, 2004; Myers and Poor, 2007; Vaughan, 2000). The carnivore skull has strong facial musculature for crushing, cutting and chewing with the dominant jaw movement being in the dorsal-ventral direction (Feldhamer et al, 2004; Myers and Poor, 2007). Carnivores usually have well-developed claws on all digits and in most felids these claws are retractable with the exception of the cheetah (Acinonyx jubatus) (Feldhamer et al, 2004). Carnivores have simple stomachs with an undeveloped cecum, because meat is easy to digest (Feldhamer et al, 2004).
For all carnivores, diet varies depending on season and availability and in some species specialized feeding habits have evolved; some are insectivorous, piscivorous, frugivorous, herbivorous or omnivorous (Ewer, 1973; Feldhamer et al, 2004). The structure of the dentition and carnassial pair is modified according to their diet (Feldhamer et al, 2004). Body size varies greatly in the Order Carnivora (Myers and Poor 2007), and a direct relationship has been found between the body mass of carnivores and the mass of their typical prey, thus body size and diet choice is closely related (Feldhamer et al, 2004; Kurtén and Anderson, 1980).
The defining characteristic of the Order Carnivora is not that they are carnivorous but is actually their morphology (Feldhamer et al, 2004). The defining morphological characteristic is the specialization of their teeth, they possess a carnassial pair (the fourth premolar and the first lower molar) which are used for cutting and shearing (Feldhamer et al, 2004; Myers and Poor, 2007; Vaughan, 2000). The carnassials are especially well developed in the predatory groups such as the felids and the hyaenids (Feldhamer et al, 2004). The canine teeth are conical, well-developed and elongated in the carnivores (Feldhamer et al, 2004; Myers and Poor, 2007). The skulls of carnivores tend to be heavy and vary in size but are distinguishable by having a large braincase and a strong zygomatic arch (Feldhamer et al, 2004; Myers and Poor, 2007; Vaughan, 2000). The carnivore skull has strong facial musculature for crushing, cutting and chewing with the dominant jaw movement being in the dorsal-ventral direction (Feldhamer et al, 2004; Myers and Poor, 2007). Carnivores usually have well-developed claws on all digits and in most felids these claws are retractable with the exception of the cheetah (Acinonyx jubatus) (Feldhamer et al, 2004). Carnivores have simple stomachs with an undeveloped cecum, because meat is easy to digest (Feldhamer et al, 2004).
For all carnivores, diet varies depending on season and availability and in some species specialized feeding habits have evolved; some are insectivorous, piscivorous, frugivorous, herbivorous or omnivorous (Ewer, 1973; Feldhamer et al, 2004). The structure of the dentition and carnassial pair is modified according to their diet (Feldhamer et al, 2004). Body size varies greatly in the Order Carnivora (Myers and Poor 2007), and a direct relationship has been found between the body mass of carnivores and the mass of their typical prey, thus body size and diet choice is closely related (Feldhamer et al, 2004; Kurtén and Anderson, 1980).