Notes: Unpopular as they can deface monuments and eat fruit crops. However, research in Israel showed that Egyptian Fruit Bats ate only ripe fruit rather than fruit for packing, processing, and transport, which is picked green. Moreover, gassing of roosts resulted in decimation of insect-eating bats and a rise in the level of insect pests. In Africa, they have been shown to be important pollinators and seed dispersers.
Similar species: In Egypt, only Tadarida bats reach anything near the size of Egyptian Fruit Bats and can be further distinguished by much larger ears, darker color, and prominent tail.
The Insectivorous Bats—Suborder Microchiroptera
The insectivorous bats form a much larger group than the fruit bats and are represented in Egypt by twenty-one different species, although several are known only from very few records. Unlike the fruit bats, the insectivorous bats hunt actively for insects, which they find using echolocation, a form of sonar. The face of most bats may appear grotesque to human eyes, but it is actually adapted to emit and receive high frequency or ultra-sonic sound waves. The bat releases a constant series of clicks through the mouth or nostrils that are then reflected off any obstacle or prey. The rebounded sound is picked up by the ears that are often very large and possess a lobe known as the tragus (absent in the horseshoe bats) at the opening. The rapidity and sensitivity of the bats’ echolocation system can be seen by simply watching bats flying around at speed at dusk, rapidly dodging and weaving in pursuit of flying insects. The insect-eating bats are probably important agents in insect pest control in agricultural areas. Since the insectivorous bats hunt by echolocation, the eyes in many species have been reduced to a greater or lesser extent.
Note: All bat tragi and noseleaves after Qumsiyah (1985) and Harrison and Bates (1991).
Identification in the field of the twenty-one species of insectivorous bats is very difficult, and in trying to identify free-flying bats, the type of flight is important: high, low, over water, fast, slow, etc., as is the habitat, and the geographical location. For instance, a large-eared bat seen in arid desert is far more likely to be Hemprich’s Long-eared Bat Otonycteris hemprichii than the Gray Long-eared Bat Plecotus austriacus or the Egyptian Slit-faced Bat Nycteris the-baica. In the hand, identification to family level can be made by looking at ear and nose patterns, tail and interfemoral membrane form, wing shape, color, and bare areas. These will all be discussed under individual families.
Rat-tailed Bats—Family Rhinopomatidae
3 species worldwide with 2 in Egypt.
Distinguished from all other Egyptian bats by the greatly elongated and very slender tail and virtual absence of interfemoral membrane. In practice, this feature is impossible to see in flight and is so slender that it can only just be made out when the bat is at rest. Rat-tailed bats do not hang from their roosts but cling upside down to the roost wall. The tail is held slightly curved out over the bat. At closer quarters, further distinguished by the pig-like snout, ears meeting over the forehead, and simple tragus. Other than size, the two Egyptian species are very difficult to tell apart, the critical difference being the relative lengths of the tail and the forearm, the tail being shorter than the forearm in the Larger Rat-tailed Bat Rhinopoma microphyllum and longer in the Lesser Rat-tailed Bat Rhinopoma hardwickii. The Larger is a much rarer species.
LARGER RAT-TAILED BAT (GREATER MOUSE-TAILED BAT) Rhinopoma microphyllum (Brunnich, 1782) Pl. 4
Larger Rat-tailed Bat (Rhinopoma microphyllum)
Subspecies occurring in Egypt: R. m. microphyllum.
Arabic: Abu dhayl al-kabir
Identification: Length 124–146mm; Tail 52–65mm; Forearm 64–71mm. Rat-tailed bats distinguished by slightly upturned snout and long, slender tail though this feature is almost impossible to see in flight. At rest, e.g., on cave wall, tail curves forward in crescent. Largest of the rat-tailed bats, though size is not a useful field feature. Eyes distinct and well-developed ears with sickle-shaped tragus. Thumbs elongated and feet slender. Long tail surrounded by flight membrane only at base. Fur fine, pale gray-brown above, slightly paler below. Lower back and abdomen, face, lips, and upper throat naked. Specimens from Upper Egypt may relate to R. m. tropica.
Range and status: Africa from Morocco south to Nigeria, and east to Sudan and Egypt. Also further east to Arabia, Iran, Pakistan, India, and to Thailand and Sumatra. In Egypt, recorded from Delta, Cairo region, Luxor (mummified), and Aswan (?). Everywhere much rarer than Lesser Rat-tailed Bat.
Habitat: Cultivated areas of Nile Valley and Delta. Has been found in same roosts as Lesser Rat-tailed Bats, though always much rarer.
Habits: Little known. In India, breeding thought to be in June. No evidence from Egypt.
Similar species: See Lesser Rat-tailed Bat below.
LESSER RAT-TAILED BAT (LESSER MOUSE-TAILED BAT) Rhinopoma hardwickii Gray, 1831
Pl. 4
Lesser Rat-tailed Bat (Rhinopoma hardwickii)
Subspecies occurring in Egypt: R. h. arabium and R. h. cystops.
Arabic: Abu dhayl al-saghir
Identification: Length 101–144mm; Tail 46–73mm; Forearm 47–59mm; Weight 10–15g. Very delicately built rat-tailed bat with very long, slender tail only bounded by flight membrane at base. In hand, forearm-to-tail ratio important. Fur fine. Color uniform pale gray-brown, paler below but with some variation. Two subspecies in Egypt. R.h. arabium from northern Egypt, inc. Cairo and the Fayoum, browner above and below, though can be gray tinged. R.h. cystops from Luxor south to Sudanese border, on average smaller, paler, grayer, described as ‘pearl gray’ below. Flight peculiar, fluttery, and bird-like.
Range and status: East and North Africa. Arabia east to Iran, Pakistan, India to Indonesia. In Egypt, R. h. arabium in Cairo and its environs, inc Wadi Digla, recorded north to Wadi Natrun, and in the Fayoum (Qasr Qarun). R. h. cystops from Asyut region south to Luxor (common in Dendera Temple), and south to Aswan and Sudanese border.
Habitat: Dry caverns and caves, often roosting deep in rock, ruins, temples, tunnels, mosques, and buildings, often on desert margins. Roosts may be shared by much rarer Larger Rat-tailed Bat and with Egyptian Free-tailed Bat Tadarida aegyptiaca.
Habits: Emerges at dusk. Colonies fairly small though up to 200 have been recorded. Food probably small insects. In autumn, lays down fat reserves and, thus, can remain active year round. In roosts, voice is audible as high-pitched chirp. Females with suckling young observed just south of Aswan at Kalabsha in July. When sharing with Egyptian Free-tailed Bat, tends to roost higher than latter species and readily distinguished by smaller size, more rapid flight, and higher voice.
Similar species: Larger Rat-tailed Bat is larger, more heavily built and, most importantly, its tail is shorter than forearm (longer in present species).
Sheath-tailed