Saccolaimus flaviventris, Peters, 1867

Bonaccorso, Frank, 2019, Emballonuridae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 350-373 : 357

18 . Yellow-bellied Sheath-tailed Bat

Saccolaimus flaviventris

French: Taphien à ventre jaune / German: Gelbbauch-Glattnasenfreischwanz / Spanish: Tafozo de vientre amarillo

Other common names: White-bellied Sheath-tailed Bat, Yellow-bellied Pouched Bat

Taxonomy. Taphozous flaviventris Peters, 1867 ,

“ Australia .”

This species is monotypic.

Distribution. Much of mainland Australia except S Western Australia and W South Australia, also including Tiwi, Groote Eylandt, Fraser, and Moreton Is; two old specimens collected in Papua New Guinea (Central Province and National Capital District), but it has not been recorded again in this century.

Descriptive notes. Head—body 75—90 mm, tail 25—35 mm, ear 19—22 mm, hindfoot 14-17 mm, forearm 72-78 mm (males) and 75-87 mm (females); weight 30-42 g (males) and 37—60 g (females). The Yellow-bellied Sheath-tailed Bat is the largest emballonurid in Australia and New Guinea. Females tend to be larger than males in body weight and other body dimensions. Dorsum isjet black; venter is white to yellow. White fur occurs on undersides of wings around forearms. Muzzle is sparsely haired or bare and sharply tapers. Exposed skin surfaces including wings, ears, fece, feet, and tail are black. Males have a well-developed gular pouch that opens anteriorly; it is absent or rudimentary in females. Males have subcutaneous gland underlying gular pouch. Radio-metacarpal sacs are absent in both sexes. Ear is triangular, with broadly rounded apex that rises barely above head. Inner surface of pinna is ribbed. Large eyes have dark brown irises. Wings are long, and wingtips fold back over mid-region of wings at rest. Tip of tail is covered with bristles. Long calcars support much of trailing edge of uropatagium. Skull is relatively flat and has prominent sagittal crest that divides into two branches toward orbits.

Habitat. Tall rainforest and eucalypt forests, mallee woodlands (low-growing bushy eucalypt), and open habitats. The Yellow-bellied Sheath-tailed Bat is relatively abundant in tall eucalypt forests of northern Australia, and its use of gallery forests with old trees in riparian areas probably help it to make nightly foraging trips into surrounding woodlands that lack large trees suitable for roosting. In New Guinea, it has been found only in coastal lowlands below elevations of 100 m; however, this might be due to limited knowledge because it occurs up to 600 m in Australia.

Food and Feeding. The Yellow-bellied Sheath-tailed Bat is insectivorous and includes beeties and moths in its diet. It typically uses a fast, direct flight while foraging for aerial insects above eucalypt forests but will fly close to the ground in open areas. Echolocation search calls are audible to humans and emitted via the mouth.

Breeding. In Australia, mating occurs in August; females have one young in December-March. Pregnancies are always restricted to the right uterine hom. Subadults are only found inJanuary—February.

Activity patterns. The Yellow-bellied Sheath-tailed Bat is crepuscular. It roosts in tree hollows and emerges at dusk to forage; it will temporarily shelter in buildings along migration routes. In Australia, the species often uses abandoned nests of Sugar Gliders (Petaurus breviceps) as roosts. Multiharmonic echolocation calls are of long duration. Harmonic with greatest intensity starts at c.20 kHz and slightly sweeps down to c.18 kHz. Characteristic frequencies are 17-5-22-5 kHz. Search phase is usually curved but can be flat. Harmonics are often 28-33 kHz and less commonly 9-13 kHz. Occasional non-harmonic pulses within a sequence have characteristic frequency as low as 15 kHz or as high as 24 kHz.

Movements, Home range and Social organization. Yellow-bellied Sheath-tailed Bats are capable of ranging up to 30 km each night as they forage. They tend to be solitary but will roost in tree hollows in groups of 2-10 individuals, particularly in late winter and spring. Temporary gatherings of breeding groups can exceed 100 individuals.

Some individuals make migratory movements in southern parts of its distribution in autumn, although most records from south-eastern Australia are of exhausted individuals found in exposed situations, which might indicate they are vagrants. Seasonal movements might also occur in mid-coastal Western Australian.

Status and Conservation. Classified as Least Concern on TheIUCNRed List. The Yellowbellied Sheath-tailed Bat has a large distribution, uses a variety of habitats, presumably has large and stable overall population, occurs in protected areas, and feces no significant threats. In northern Australia, acoustic surveys using full-spectrum detectors that record harmonic profiles suggest that it is relatively common. The species has reported incidences of viral Australian bat Lyssavirus that can be transmitted to humans. Feral European honeybees {Apis melliferd) commonly take over tree hollows in arid Australia and displace Yellow-bellied Sheath-tailed Bats. Habitat clearing and replacement of perennial tree species in arid areas have reduced area of occupancy.

Targeted surveys along southern coast of New Guinea will more clearly define extent of occurrence and habitat associations. Additional ecological research should be targeted in southern parts of its distribution to better understand its apparent migratory behavior and possible use of torpor. The Yellow-bellied Sheath-tailed Bat is rare in south-eastern Australia, where records possibly represent occasional summer-autumn visitors, vagrants, or small resident populations.

Bibliography. Bonaccorso (1998), Flannery (1995a), Hall & Richards (1979), Lumsden & Menkhorst (1996), Milne (2002), Pennay et al. (2004), Richards (2008a), Strahan (1995).

Figures

On following pages: 4. Hamilton'sTomb Bat [Taphozous hamiltoni); 5. Hildegarde'sTomb Bat (Taphozous hildegardeae}; 6. Long-winged Sheath-tailed Bat (Taphozous longimanus); 7. Black-beardedTomb Bat (Taphozous melanopogoh); 8. Theobald'sTomb Bat (Taphozous theobaldi); 9. Indonesian Tomb Bat (Taphozous achates); 10. Arnhem Sheath-tailed Bat (Taphozous kapalgensis}; 11. Coastal Sheath-tailed Bat (Taphozous australis}; 12. Common Sheath-tailed Bat (Taphozous georgianus); 13. Hill's Sheath-tailed Bat (Taphozous hilli); 14. Troughton's Sheath-tailed Bat (Taphozous troughtoni); 15. Pel's Pouched Bat (Saccolaimus peli); 16. Bare-rumped Sheathtailed Bat (Saccolaimus saccolaimus); 17. Papuan Sheath-tailed Bat (Saccolaimus mixtus); 18. Yellow-bellied Sheath-tailed Bat (Saccolaimus flaviventris).

Distribution. Much of mainland Australia except S Western Australia and W South Australia, also including Tiwi, Groote Eylandt, Fraser, and Moreton Is; two old specimens collected in Papua New Guinea (Central Province and National Capital District), but it has not been recorded again in this century.