Читать книгу A Field Guide to the Mammals of Egypt - Richard Hoath - Страница 8
ОглавлениеThis guide is designed to help the reader identify mammals seen in the field in Egypt. Sometimes this can be straightforward. A rabbit-like mammal with very long ears and a short, black-and-white patterned tail is clearly a Cape Hare Lepus capensis, while a goat-like mammal with knobby, back-curved horns and strikingly patterned limbs seen in the mountains of South Sinai can safely be identified as a Nubian Ibex Capra ibex, once the domestic goat is eliminated. However, very often things are not so clear-cut. Mammals are often very difficult to observe. They are often very shy and secretive, and while less than 3% of all bird species are nocturnal, making things relatively straightforward for the ornithologist (in Egypt, the percentage is 2.61%, using Goodman and Meininger [1989]), many mammal species, including most of the difficult-to-identify rodents and bats, are only active at night. And as most of the prey species are active by night, so are the predators.
The first step is to try and match the mammal seen to the plates, taking note of distinguishing features, prominent markings, and relative size. Each individual plate has all the species represented to scale, and actual size can be found by referring to the text. Proportions, particularly those of the tail, hind feet, and ears can all be of importance. The summarized text opposite each plate emphasizes the key identification points. Thus, a desert rodent bounding across the road at night on its hind legs, with a long, black and white tufted tail can be narrowed down to one of the jerboa species from the plate (Allactaga sp. or Jerboa spp.).
The second step is to check the ranges of the likely species to the maps adjacent to the individual species’ texts. These maps show the range within which each species may be found, assuming suitable habitat. Ranges expand and contract due to natural and human factors, so range alone cannot firmly identify a mammal but can at least highlight the most likely species. Thus, the jerboa cited above is almost certain to be the Lesser Egyptian Jerboa Jaculus jaculus in the Eastern Desert. In Sinai, it must be compared with the Greater Egyptian Jerboa Jaculus orientalis while along the northern coastal strip the Four-toed Jerboa Allactaga tetradactyla is also a possibility. That said, many species, especially some of the bats and sea mammals, may enjoy wider ranges than have been indicated, as lack of research may explain the relatively few records of certain species rather than natural scarcity.
Third, refer to the text. Any other information such as habits and habitat, associated species, or even time of day observed can be important. For example, a mouse seen in rocky habitat in the Eastern Desert by day is more likely to be the Golden Spiny Mouse Acomys russatus than the Cairo Spiny Mouse Acomys cahirinus, which is largely nocturnal. Similarly, a robust gerbil-like rodent seen in a salt marsh habitat by day is more likely to be a Fat Sand Rat Psammomys obesus than one of the jirds Meriones spp. Secondary details may also be useful such as any tracks or spoor and, for this purpose, some of the more distinctive tracks have been illustrated after the species plates. Cranial characteristics and detailed dental formulae are beyond the scope of a field guide but can be found in the literature detailed in the Selected Bibliography.
Each mammal species has its own entry giving the following details.
Species name: The most widely used English name is given in bold with alternative names following in brackets. The scientific name is then given for the most part following Nowak (1999), but see below for taxonomic note. Subspecies, where relevant, generally follow Osborn and Helmy (1980). Finally, the Arabic name or names are given where possible, following Wassif (1995). For ease of use, animal names are capitalized to avoid confusion, thus the Striped Hyena Hyaena hyaena can be differentiated from a hyena that happens to be striped.
Names for parts of mammals used in the text
Identification: The total length of the species is given from the snout to the tip of the tail, excluding any terminal tuft. The tail length is then given. Head and body length, a frequently used parameter, can be calculated by subtracting tail length from total length. Frequently a range is given, reflecting variation in size between individuals, sexes, or subspecies, and it is sometimes surprising how great this variation can be. In the larger mammals, shoulder height is also given and, in the bats, the forearm measurement is given. Where possible, the weight is given. All measurements given are from Egyptian specimens, where possible, or at least from specimens from the region and refer to the published data in Osborn and Helmy (1980), and Harrison and Bates (1991). In many cases, these measurements have been checked to museum specimens (see acknowledgments). Overall appearance and key distinctive features are then given, followed by a detailed description of the external appearance of the species. Where relevant, there may be a discussion of variation, either clinal or by subspecies.
Range and Status: The global range of the species is given followed by a detailed description of the range in Egypt. The status of the species is given based on published records, recent sightings, as well as whether the species is protected under Egyptian law (or has been recorded from any Protected Area) or whether it is covered under international treaties, such as CITES, or listings, such as IUCN.
Habitat: A description is given of the habitat type in which the species is normally found.
Habits: A description of the habits of the species is given. This can include such details as when active (nocturnal, diurnal, or crepuscular), nature of den or burrow, food, acuity of the senses, recorded predators, distinctive behavior, reproductive details including gestation period, breeding season, and litter size. Where possible, these details are based on published records from Egypt but for species very rare in Egypt, e.g., Aardwolf Proteles cristatus or Leopard Panthera pardus, behavioral details from outside Egypt are given prefaced by the word ‘elsewhere’ to show that this is the case.
Associated Species: Many mammals, particularly the rodents, can be found in similar habitat, even sharing burrows with other species. When this has been recorded, associated species are given.
Notes: Any useful additional information, particularly of a taxonomic nature, is given under this heading. As stated above, this guide broadly follows the taxonomy of Nowak (1999), but where there are differences these have been noted. Differences with other important works may also be noted such as the taxonomic treatment of the hyraxes in Kingdon (1997) or the Small-spotted Genet Genetta genetta in Harrison and Bates (1991).
Similar Species: The key identification characteristics with species likely to give confusion are highlighted in this section.
For every species described, there is a map showing the range in which the mammal concerned is likely to be found. These maps are based on published records augmented by reliable field observations.
| Gray shading indicates the area in which the species has definitely been recorded. The species may be expected in suitable habitat within this range according to the mammal’s status as given in the text. | |
| Black stippling indicates a historical range but one in which the species can no longer be expected, or a range in which the animal may now be found only in widely scattered pockets due, for example, to hunting, as in the Nubian Ibex. | |
| A black dot indicates an isolated record outside the normal range of the species, or a number of records from a very limited area, for example, one of the Western Desert oases. | |
| A question mark indicates a record that has not been substantiated, is questionable for some reason, or that is very old and for which there have been no more recent sightings. |
Every species of mammal that has been reliably recorded in Egypt has been illustrated, most groups in color but the bats and the cetaceans in black and white. Each plate shows each individual mammal to scale. The plates are based on three main sources. Where possible, the living mammal has been seen and sketched and the institutions that have made this possible are recognized in the acknowledgments. For the detailed work, particularly with the difficult groups such as the Gerbillus gerbils and the Meriones jirds, use has been made of well-preserved museum specimens from respected institutions. This has been invaluable and the collections used have likewise been acknowledged. Finally, photographic references have been used. Where necessary or helpful, ink drawings supplement the main illustration, for instance, in the details of the horseshoe bats’ nose-leaves and sellae, or to show some aspect of behavior.
The measurements recorded in the individual species accounts are, for the most part, those from Osborn and Helmy (1980) and in manycases confirmed to museum specimens. These relate to specimens from Egypt as opposed to specimens from outside the country, which may or may not be locally accurate. The measurements for the bats are generally those published by Qumsiyeh (1985). Where there are no Egyptian specimens readily available, as in the Marbled Polecat Vormela peregusna for instance, the measurements are taken from the closest reliable source, e.g., Harrison and Bates (1991). Key measurements are as follows.
Total length: Length taken from the tip of the nose to the tip of the tail, excluding any terminal tuft.
Tail length: Length taken from the tip of the tail, excluding any terminal tuft, to the base of the tail.
Head and body length: Length from the base of the tail to the tip of the nose, which may be obtained by subtracting the tail length from the total length.
Ear length: Length of the ear from the tip, excluding any tuft, to the base.
Forearm length: For the bats, the forearm length is given being the distance from the elbow to the wrist, i.e., the ulna.
Hind foot length: Length of the hind foot from the back of the heel to the tip of the toe, excluding the claws.
Shoulder height: The height at the shoulder used in the larger mammals, e.g., the ungulates.
All the above measurements are in millimeters for the smaller species, centimeters for the larger species such as the ungulates, or, in the case of the cetaceans, in meters. While this may seem ungainly, this reflects the accuracy with which mammals of various types are generally recorded. To describe Savi’s Pygmy Shrew as .07m total length or the Fin Whale as 22,000mm long would be to overgeneralize the former and be overly specific about the latter and to misrepresent them both.
Weight: The weight of a mammal is given, where known, in grams for the smaller species and kilograms for the larger species and tons for the larger cetaceans. See the above note on measurements.
