Читать книгу A Field Guide to the Mammals of Egypt - Richard Hoath - Страница 9
ОглавлениеThe Insectivores—Order Insectivora
The insectivores is a heterogeneous order of mammals that includes the familiar hedgehogs, shrews, and moles along with the much less familiar golden moles, solenodons, otter shrews, and tenrecs. In the past, elephant shrews, tree shrews, and flying lemurs, or colugos, have also been lumped into the order, though each is now generally assigned to the orders Macroscelidea, Scandentia, and Dermoptera, respectively. Being such a catch-all group, it is difficult to assign general characteristics to the insectivores. However, they are all small, none heavier than 1,500g and generally much smaller and, indeed, include Savi’s Pygmy Shrew Suncus etruscus, the smallest terrestrial mammal in the world, tipping the scales at a mere 1.5–2.0g. The snout is generally slender, elongated, and highly mobile, the eyes are small or even absent externally, and the fur is short and dense. Many are nocturnal though some, such as the shrews, are active day and night. While the larger insectivores take small vertebrate prey, and some include fruit in their diet, they feed predominantly (as their name suggests) on insects and other invertebrates. Scent is the primary sense used in locating prey.
Everything points to the insectivores being a very ancient group. They have relatively small brains with few convolutions, the testes do not descend into a scrotal sac, the teeth are primitive and well differentiated, and they possess a cloaca, a common exit for the urino-genital and fecal systems. Being an old group though, some members have developed very specialized adaptations: the moles and golden moles have adapted to life underground, the hedgehog and some tenrecs have developed spines, and some shrews, poisonous saliva.
Egypt has relatively few insectivore species, two hedgehogs (though this is questioned on taxonomic grounds) and six shrews, though again, their taxonomy is still a matter of debate. Two of these species, the House Shrew Suncus murinus and the Savi’s Pygmy Shrew, are known only from single records and certainly the former is introduced. The paucity of insectivores in Egypt is probably due to the lack of suitable habitat. Many insectivores prefer moist habitats where food and water are plentiful (shrews may eat more than their own body weight daily). Relatively few species are found in the desert, hedgehogs being the main exception, though even they are absent from true desert. The Sahara seems to have provided a very effective barrier to the insectivores as only one species, the Ethiopian Hedgehog Paraechinus aethiopicus, has been recorded in the south of the country. Of the six shrews, the three Crocidura shrews are African species and a fourth, Flower’s Shrew Crocidura floweri, is endemic, while the others have wide ranges over Eurasia. It is probable that these four current Crocidura shrews became isolated in northern Egypt during the climatic warming around six thousand years ago.
The Hedgehogs and Moonrats—Family Erinaceidae
17 species worldwide with 2 in Egypt.
Of the family Erinaceidae, only the hedgehogs, subfamily Erinaceinae, are represented in Egypt, the moonrats being confined to Southeast Asia north to China. The hedgehogs are amongst the most familiar and distinctive insectivores characterized by their relatively large eyes and ears, short, stocky build, and by their entire upper parts being covered in a coat of short spines. Some, but not all, hedgehogs can roll up into a near impregnable ball of spines, the vulnerable underparts and facial region being completely protected.
There is little agreement about the taxonomy of the hedgehogs, even within Egypt. Here, two species are recognized. The Long-eared Hedgehog Hemiechinus auritus is quite distinctive and placed in the genus Hemiechinus based on cranial characteristics, ear size, and the absence of a spineless ‘parting’ on the crown. It is probably the most likely of all of Egypt’s insectivores to be encountered and certainly the most widespread. The second species, the Ethiopian Hedgehog, is assigned to the genus Paraechinus. Some authors, notably Osborn and Helmy (1980), divide the Ethiopian Hedgehog into three species, the Desert, South Sinai, and Ethiopian Hedgehog. The three are differentiated primarily by spine coloration and facial pattern and are considered by most current authors as one species, the Ethiopian Hedgehog Paraechinus aethiopicus, with three geographically distinct populations in Egypt: the Mediterranean coastal desert, the mountains of South Sinai, and the southern Eastern Desert, respectively. Because of the degree of variation within hedgehog species (some authors split the European Hedgehog Erinaecus europaeus into as many as twelve different species,) it is probable that these three are indeed three isolated populations of the same species, which is how they are treated here.
LONG-EARED HEDGEHOG Hemiechinus auritus (Gmelin, 1770)
Pl. 1
Long-eared Hedgehog (Hemiechinus auritus)
Subspecies occurring in Egypt: H. a. aegyptius and H. a. libycus.
Arabic: Qunfid tawil al-udhun
Identification: Length 151–245mm; Tail 15–39mm: Weight 400–500g. A small, rather pale hedgehog with distinctively large ears. Upper parts covered in rather short spines, reaching some 1.5cm in length along the back, that are brownish at the base with a broad, cream subtcrminal band and white tip. H. a. libycus averages paler than H. a. aegyptius, with a slightly shorter tail. The underparts are white, often tinged yellow, and the legs and feet, white to whitish. Rather long-legged, especially apparent when trotting. Facial region without spines, with pale brown fur. Snout long and pointed. Ears large, rounded, whitish, and translucent. Unlike other hedgehogs, they emerge well clear of the spines. Tail short. Wide range of vocalizations including snuffling, growling when threatened, and a cat-like hissing.
Range and status: Wide range from Libya and Egypt across Sinai to Israel, north to Syria, south to eastern Arabia, and east through Iraq, Iran, Afghanistan, Pakistan and India north to Russia and on to Mongolia. In Egypt, restricted to the north. H. a. aegyptius found in North Sinai (few records from al-Arish area), much of the Delta, and both sides of the Nile Valley from the barrages south to just south of Beni Suef. Also the Fayoum, where reportedly common. H. a. libycus is found on western margin of Delta including Wadi Natrun and across the northern coastal desert to Sallum, seemingly a frequent road kill.
Habitat: Not a species of true desert. Generally found around human settlements and agricultural activity. Also gardens, buildings, and more densely vegetated areas of coastal desert, including salt marshes.
Habits: Nocturnal though occasionally active by day. Spends day in a simple burrow up to lm long, which it excavates itself. Diet omnivorous, probably largely insects, but will also take fruit and small vertebrates. Possibly an important pest control. Hearing and scent acute. Predators include the Eagle Owl Bubo bubo and probably also the Jackal Cams aureus, Swamp Cat Felis chaus, etc. Unlike other hedgehogs, does not roll into a ball when threatened. Gestation 36–37 days. Female enlarges end of tunnel to make a nest chamber. Elsewhere, breeding season from May to October with peak in summer. Litter size 1–5.
Associated Species: The Long-eared Hedgehog has been found in the burrows of the Fat Sand Rat Psammomys obesus.
Notes: Kingdon (1997) also assigns the Ethiopian Hedgehog to the genus Hemiechinus but note the differences outlined below in the description of that species.
Similar species: Readily told from the Ethiopian Hedgehog by small size, the very prominent ears, and lack of ‘parting’ in frontal spines. In hand, also differentiated by uniform pale underside. Habitat is also important—a hedgehog in true desert is not likely to be this species. Porcupines much larger.
ETHIOPIAN HEDGEHOG Paraechinus aethiopicus (Ehrenberg, 1833)
Pl. 1
Ethiopian Hedgehog (Paraechinus aethiopicus)
Subspecies occurring in Egypt: P. a. aethiopicus, P. a. deserti, and P. a. dorsalis.
Arabic: Qunfid habashi
Identification: Length 184–258mm; Tail 13–30mm: Weight to 500g. Typical hedgehog form with rather large ears, though not as proportionately large as in the Long-eared Hedgehog. Upper parts covered in spines up to 2.7cm long. Dorsal spines dark, tipped with pale brown. This gives a very dark impression of the back when seen from above, much darker than the Long-eared Hedgehog. Frontal spines divided by a bare patch or parting, extending some 3cm back, but not a field feature. Spines along flank shorter and pale tipped. Underparts white with dark patches, rather variable. Head with rather pointed snout, but not as pointed as Long-eared Hedgehog. Face bicolored or all dark. Snout, chin, and throat dark brown. Forehead to just above eye and down sides pale. Ears large, broad-based, and extending beyond spines. Legs dark brown. Tail short.
Range and status: Egypt, including Sinai, south through Sudan to Somalia and west to Libya, Algeria, Morocco, and Mauritania. Also Arabia north to Lebanon. In Egypt, P. a. aethiopicus is known only from the southern Eastern Desert including the Gebel Elba region. P. a. deserti recorded from the north coast from Sallum to the western margin of the Delta. P. a. dorsalis restricted to South Sinai.
Habitat: Deserts and semi-deserts, rocky wadis, and plains. Also gardens and oases.
Habits: In Egypt, virtually unrecorded and little known elsewhere. Nocturnal, probably most active at dawn and dusk. Spends day in burrow excavated by itself often under dense shrubbery. Home range probably small, within 200–300m of the burrow. Diet presumably similar to Long-eared Hedgehog, but reportedly more carnivorous including insects, grubs, small vertebrates, and probably fruit, roots, etc. Food may be stored underground. Predators unknown but possibly Eagle Owl. Gestation 30–40 days. Female gives birth to young in burrow or in vegetation. Litter size 1–4. One or more litter per year.
Notes: See comments on family taxonomy.
Similar species: For Long-eared Hedgehog, see previous species.
The Shrews—Family Soricidae
c. 246 species worldwide with 6 in Egypt.
The shrews include some of the world’s smallest mammals and indeed worldwide none exceeds 29cm in length or 40g in weight, and most are much smaller. Shrews are characterized not only by their small size but also by their generally mouse-like appearance, the elongated, pointed snout, small eyes and ears, and soft pelage often punctuated by longer bristle hairs, especially on the tail. The absence, presence, and degree to which these occur can be important in identification.
As a consequence of their small size, shrews have a very high surface area to volume ratio and must consume enormous amounts of food relative to their body size just to keep their metabolism going. Thus, shrews are almost constantly on the search for food, which consists largely of insects, arachnids, earthworms, and other invertebrates as well as occasional small vertebrates. In some species, killing is assisted by poisonous saliva. A further adaptation to the shrew’s frantic pace of life is refection noted in many, if not all shrew species. In refection, the rectum is extended and licked possibly so that the shrew can obtain nutrients from its food that might otherwise be lost in the feces. As is usual for animals with such a high metabolism, the life span of a shrew is generally very short, few survive beyond their first year. Their short lives are also due to the fact that shrews are born with one set of teeth. Once these wear out then the animal will die of starvation. They are thought to suffer less from predation than, for example, the smaller rodents, due to their distasteful flesh caused by noxious secretions from skin glands. That being said, their remains have been found in the pellets of Barn Owls Tyto alba.
The paucity of shrew species, mentioned under the general discussion of the insectivores, is paralleled by there being relatively few specimens of most species taken in Egypt. Indeed, only the Greater Musk Shrew Crocidura flavescens can be called at all widespread or common, and no other shrew has been recorded south of the Fayoum. This may reflect the genuine scarcity of shrews in Egypt, though the Nile Delta and Valley would appear to provide the moister habitat, rich in food and water, that shrews favor. It more likely reflects the fact that they are easily overlooked. Their small size (combined with preference for densely vegetated habitat) and the difficulty in trapping them makes them hard to locate or study. Savi’s Pygmy Shrew is too small to trap in conventional traps even if it were attracted by the same bait put out for the more vegetarian rodents. While it is probable that the isolated record of the House Shrew is of a single, introduced animal at the port of Suez, the Delta may support larger numbers of Savi’s Pygmy Shrew than the number of specimens collected would seem to indicate. The records of mummified specimens of Flower’s Shrew and the Dwarf Shrew Crocidura nana from Thebes in Upper Egypt may indicate that shrews did have a wider range in Egypt in pharaonic times when the climate was milder. Mummified shrews of as yet unidentified species have also been found at Saqqara.
It is probable, depending on their numbers and population density, that shrews consume a large number of agricultural insect pests.
Shrews are often referred to in Arabic by the generic terms for mouse or weasel: far, ‘irsa.
GREATER MUSK SHREW (GIANT MUSK SHREW, AFRICAN GIANT SHREW, GIANT SHREW) Crocidura flavescens (I. Geoffroy St-Hilaire, 1827)
Pl. 2
Subspecies occurring in Egypt: C. f. deltae.
Arabic: Zibab ‘imlaq
Identification: Length 163–219mm; Tail 57–84mm; Weight c. 40g. Large, rather dark, long-tailed shrew. Upper parts uniform dark brown, glossy on flanks, fur soft, short, and dense. Underparts dark grayish. Feet either grayish or brown. Head with typical pointed snout. Teeth white. Eyes visible but small. Ears large, sparsely haired, and, despite size, barely stand out from dense fur. Tail dark brown, about half of head and body length, sparse hair with long bristles except along last third of length.
Greater Musk Shrew (Crocidura flavescens)
Range and status: Patchily throughout Africa from Cape along eastern southern Africa north through East Africa to Ethiopia, Sudan, and Egypt, and west to Sierra Leone. In Egypt, easily the most widespread shrew, but even so, confined to the Delta and the Nile Valley south to Dahshur. Historically abundant in the region south of Damietta. Reported common at Abu Rawash and around Zaqaziq. Also the Fayoum where reportedly common.
Habitat: Moist areas with dense vegetation including canal embankments, irrigated fields, and cultivated areas. In the Fayoum, around settlements and gardens.
Habits: Like most shrews, may be active throughout the day and night. Territorial and solitary. Builds a nest of damp, matted grass. Diet mainly insects and other invertebrates including snails, but may also take small vertebrates with frog carcasses having been recorded in their nests. Predators include the Eagle Owl. Gestation c. 18 days. Litter size 2–6. Elsewhere, breeding season during wetter months.
Similar species: Other shrews. Distinguished by much larger size except from the very rare House Shrew, which has a proportionately shorter tail, thick at base, and lighter underside. Distinguished from the Flower’s Shrew, Lesser White-toothed Shrew Crocidura suaveolens, and Dwarf Shrew by dark underside and uniformly dark tail. All much smaller. In hand, first has tail bristles only along first half of tail; other two have bristles along entire length.
FLOWER’S SHREW Crocidura floweri Dollman, 1915
Pl. 2
Flower’s Shrew (Crocidura floweri)
Monotypic
Identification: Length 112–129mm; Tail 55–58mm. Small shrew, endemic to Egypt. Upper parts rather pale pinkish brown. Flanks and underparts whitish. Feet grayish white. Tail proportionately long, up to 75% of the head and body length, reddish brown above, whitish below with bristles only on first half. Bristles sparse and grayish white.
Range and status: Only known from Egypt where confined to Nile Delta and the Fayoum. Specimens recorded from Giza, Baltim, and a single record from the Fayoum. Very rare with no recent published records. Possibly extinct.
Habitat: Agricultural areas.
Habits: Unknown. Presumably similar to other shrews. Predators include Cattle Egret Bubulcus ibis as one specimen recorded from the stomach of that species.
Similar species: Other small shrews from which distinguished by cinnamon tinge to upper parts and sparse bristles only extending along basal half of the tail.
DWARF SHREW (MUSK SHREW) Crocidura nana Dobson, 1890
Pl. 2
Monotypic
Arabic: Zibab qazam
Identification: Length 76–102mm; Tail 28–40mm. Very small, pale, long-tailed shrew. Coat short and dense, upper parts grayish, tinged brown, flanks paler and pale gray below. Head typically shrew-like, grayish with whitish throat and chin. Feet whitish, almost naked. Tail proportionately long, about 60% of head and body length. Gray above, whitish below with numerous, whitish bristles along entire length.
Range and status: From Egypt south through East Africa to Zimbabwe. In Egypt, recorded only from the southernmost part of the Delta south to Cairo (1 record).
Dwarf Shrew (Crocidura nana)
Habitat: Similar to other shrews. Recorded from moist farmland, canal banks, etc.
Habits: Unknown. Presumably similar to other shrews. Nest reportedly built of twigs and cotton bolls.
Notes: A further species, Crocidura religiosa, has been described from ancient Egyptian mummies (the Dwarf Shrew itself is known from mummified remains from Thebes). However, many authors reject this species and, unless a living specimen is found, it cannot be distinguished in the field and can only be identified from skeletal characteristics; thus, it has not been included. Bonhote (1909) claimed to have obtained one live specimen of C. religiosa at Abu Rawash, but provided no details.
Similar species: Other small shrews. For Flower’s Shrew, see previous species. From Lesser White-toothed Shrew told by proportionately longer tail and paler, grayer color above. Species’ known distributions in Egypt do not remotely overlap. Distinguished from Savi's Pygmy Shrew by larger size and proportionately longer tail.
LESSER WHITE-TOOTHED SHREW Crocidura suaveolens (Pallas, 1811)
Pl. 2
Subspecies occurring in Egypt: C. s. portali and C. s. matruhensis.
Identification: Length 80–112mm;Tail 25–40mm;Weight 3.5g. Small shrew with proportionately short tail. Upper parts brown to brownish gray, underparts whitish with no sharp demarcation along flanks. Feet whitish. Head with broad snout narrowing quickly to elongated proboscis. Ears rather small but distinct, standing out from fur. Eyes typically small. Tail same color as upper parts, indistinctly paler below. Bristles extend entire length of tail. Has a distinct musky odor.
Lesser White-toothed Shrew (Crocidura suaveolens)
Range and status: Very wide range over much of southern Europe, west to Scilly Isles and north to northern Poland, east throughout Asia from Middle East to China, Korea to Japan. Isolated records from Arabia. In Egypt, very few records. C. s. portali recorded from South Sinai west of St. Katherine’s Monastery, and from near Suez. C. s. matruhensis is known from only a few specimens taken west of Mersa Matruh. Despite the paucity of Egyptian records, the wide range of this species elsewhere may mean that it could turn up in areas in Egypt other than those in which it has so far been recorded.
Habitat: In Sinai, taken from 1,500m inside a small monastery west of St. Katherine. On the north coast, taken from Fat Sand Rat burrows in salty depressions near coast. Elsewhere, recorded from a wide range of habitats including woodland, gardens, marshlands, rocky hill slopes, vegetated dunes, and coastal plains.
Habits: Unknown in Egypt. Elsewhere, little known in wild but probably much like other shrews. Active throughout day and night though with peak in evening. Does not excavate a burrow but lives in cavities or crevices or in thick tangles of vegetation. Diet consists of insects, snails, worms, and other invertebrates. Gestation 24–32 days. Litter size 1–7. Once mobile, young follow female around by caravaning, where first of litter grabs mother by the rump, the second grabs the first, etc., forming a train.
Note: Certain authors reorganize C. s. matruhensis as a separate species, C. whitakeri.
Similar species: Other small shrews. For Flower’s Shrew and Dwarf Shrew, see those species. Much smaller than House Shrew. Much larger than Savi’s Pygmy Shrew with relatively smaller ears.
HOUSE SHREW Suncus murinus (Linnaeus, 1766)
Pl. 2
Subspecies occurring in Egypt: tentatively 5. m. sacer.
Identification: Length 155–240mm; Tail 50–85mm. A large, robust shrew with a proportionately rather short tail. Coat short. Upper parts brown, hairs gray at base, underparts grayish white with indistinct demarcation. Feet white. Head large with relalively small, rounded ears that still project beyond fur. Tail about one half of head and body length. Very thick at base narrowing toward tip. Brown with silvery bristles along entire length.
House Shrew (Suncus murinus)
Range and status: Largely Asiatic, from New Guinea west through Southeast Asia to India and Sri Lanka and north to Taiwan and Japan. Outside this range also in isolated populations at seaports throughout Arabia to Egypt and Sudan. In Egypt there is one (two according to Wassif and Hoogstral [1953]) record of the species at Suez. This was almost certainly ship-borne and there is no evidence that the House Shrew has established a viable population at the port.
Habitat: The House Shrew appears to be a commensal, at least in the Arabian region, found in houses, warehouses, and other buildings. Also recorded from garbage heaps, gardens, and walls.
Habits: Unknown in Egypt. Probably as other shrews but much more tied to humans. Elsewhere, reported to be largely nocturnal and noisy. Recorded from Barn Owl pellets.
Similar species: In Egypt, only the Greater Musk Shrew is as large. House Shrew can be distinguished by proportionately shorter tail with much thicker stock and silvery bristles along entire length. Range and habitat different.
SAVI’S PYGMY SHREW (PYGMY WHITE-TOOTHED SHREW, COMMON DWARF SHREW, SAVI’S DWARF SHREW, ETRUSCAN SHREW) Suncus etruscus (Savi, 1822)
Pl. 2
Savi’s Pygmy Shrew (Suncus etruscus)
Single Egyptian specimen probably S. e. etruscus.
Identification: Length 62–81mm; Tail 21–32mm; Weight 1.5–2.0g. A tiny shrew, one of the smallest mammals in the world, with relatively large ears. Upper parts gray-brown with reddish tinge, long hairs interspersed in short dense coat. Underparts grayish, hairs gray, tipped white, with indistinct demarcation. Feet whitish. Ears large and stand well clear of fur. Tail narrow, over half head and body length, brown above, paler below, and scattered with bristles along entire length.
Range and status: Much of southern Europe, including the Canary Isles, from Iberia east to Turkey and on to Iraq, Iran, India to China and parts of Southeast Asia to Borneo. Also North Africa south to Ethiopia and Madagascar. In Egypt, known only from one specimen in the Paris Museum taken in the Delta. It is not known whether this shrew is just very rare, possibly extinct, or whether it is so small it is overlooked. Apparently it is too small to be caught in conventional mousetraps.
Habitat: Unknown in Egypt. Elsewhere, from farmland, in gardens, olive groves, along old walls, and buildings.
Habits: Little known but presumably much as other shrews. Nests in cavities in walls or rocks, or beneath tree roots.
Similar species: See other small shrews. Minute size and relatively large ears should be diagnostic.
