Have you seen their large eyes?
The lesser dog-faced fruit bat usually cluster in small groups and forage with their keen sense of smell and sight. Unlike Microchiroptera bats, Megachiroptera bats are not capable of laryngeal echolocation as such a mechanism is too energetically expensive to retain. So, the lesser dog-faced fruit bat has its distinctive large eyes for smooth navigation at night.
In addition, the combination of sound and sight is required for the navigation of the lesser dog-face fruit bat. In a study (Heffner et al. 2008), it was shown that hearing is used to direct eyes to source of sound for sound localization.
|Taken by Doug Wechsler, under Some Rights Reserved|
Sleeping on beds is too boring.
All animals need to rest after a long day of feeding - bats are no different! As you may have seen on television or in movies, bats have very peculiar resting (roosting) behaviour. In the day, the lesser dog-faced fruit bat finds shelter in shaded trees, tree-ferns and near entrances of caves.
The Perfect Life: Make a home and find a mate
|[A] to [F] are variants of Palmate type tents. (Tan et al. 1997)|
Types of tents
- Apical and stem
These tents serve to keep the furry little bats from vicious predators and also shelters them from wind and rain. An interesting fact about roost tents: Males make tents and recruit females (Tan et al, 1997). Males are also observed to have high roost fidelity as a resource defence strategy (Chaverri and Kunz 2006). Females will then choose males based on roost quality. Thus, males have high productivity pay-off if they successfully recruit females and exclude other males from roosts.
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1. Ecology | 2. Description | 3. Distribution & Habitat | 4. Importance of bats around the world | 5. Conservation | 6. Taxonomy | 7. References |
Bats are mammals with powered flight!
The body structure of bats enable them to fly great distances. Bats have modified skeletons and use various muscles for flight. They do not have reinforced sternums, unlike birds which power their flights with their breast muscles. Also unlike feathers on bird, bats have highly articulated and flexible wings which enable them to fly with greater manoeuvrability, increased lift and lesser drag.
(Iriarte-Diaz and Swartz, 2008)
Much research has been conducted to detail the mechanisms of flight in bats, especially for the lesser dog-faced fruit bats. In this species, change in flight direction due to changes in body orientation during up-stroke has been observed. On the other hand, changes in flight direction is restricted during the down-stroke portion of the wing-beat cycle.
Lesser dog-faced fruit bat are fruigivores!
Do you know what is a fruigivore?
|As a frugivore, the lesser dog-faced fruit bat usually eats fruits, figs, nectar and pollen from flowers. Leaves are high in protein while fruits are high in energy content to allow it to fly through the air.|
As it has a tiny mouth, smaller fruits are swallowed while larger fruits are chewed. Sometimes it will just drink the juice after chewing and spit out the dehydrated pulp.
|Matico (Piper aduncum)||Tiup tiup (Adinandra dumosa)|
In Malaysia, the keystone resources to sustain the population of bats are Ficus spp, Piper aduncum and Pternandra echinata. Seasonal feeding is also present for the lesser dog-faced fruit bats in Malaysia. It feeds mainly on fruits in months of March to June, which coincides with local fruiting seasons. On the remaining parts of the year, it feeds on floral parts.
The Cynopterus brachyotis is the most common fruit bat to be found in Singapore. It belongs to the Megachiroptera suborder which are frugivores with long heads, long jaws, and large eyes for excellent vision. As a result, they do not require to use echolocation for navigation in the twilight and in caves.
|Although Megachiroptera refers to megabats, they are not necessarily huge in size and can range from as small as 6 cm to as large as having a wingspan of 1.7m and weighing up to 1.6kg. Of the Megachiroptera, the lesser dog-faced fruit bat is considered relatively small.|
Can you guess which one is the lesser dog-faced fruit bat?
|BAT [A]||BAT [B]||BAT [C]|
That's right! Bat [A] is the lesser dog-faced fruit bat.
Bat [A] : Lesser Dog-faced Fruit Bat, Cynopterus brachyotis
Bat [B] : Black Flying Fox, Pteropus alecto
Bat [C] : Spectacled Flying Fox, Pteropis conspicillatus
How to know which one is the lesser dog-faced fruit bat?
Lesser dog-faced fruit bats typically mature between 70 to 127 millimetres for head and body, with an average wingspan of about 370 millimetres and average wing area of 21 cm2 (Hodgkison et al, 2004). At such a small size, it weighs only about 21 to 45 grams. The greyish young will develop into brown adults with collars, where the males have darker orange collars and the females have yellow collars. You can see that it gets its name from the characteristic long dog face and jaw which is obvious in the pictures below! Other features include dark spotted wings, white edges of ears and wing bones, long forearms of 55 to 92 millimetres, a small tail of about 6 to 15 millimetres and of course, large eyes.
Fur colour: Grey
Collar: No distinct collar
Fur colour: Brown
Collar: Females have yellow collars while males have dark orange collars
In the picture at the middle showing the underside of the skull, the long dog face is because of the elongated bony palate which forms the top of the mouth.
In the picture on the right, you can see the flat quadrate teeth adapted for biting through hard fruit skins and crushing fruits to bits.
3. Distribution & Habitat
Lesser dog-faced fruit bats can be found mainly in Southeast Asia and India. Areas include:
- Southwest and Northeast India
- Andaman and Nicobar Islands
- Southern China
- Sourthern Burma
- Sri Lanka
- Malay Peninsula
- Lesser Sundal Islands
- Kangean islands
- Coastal areas
- Lowland primary and secondary forests
- Cultivated areas
- Built-up environments
4. Importance of bats around the world
Fruit bats are important seed dispersers!
The lesser dog-faced fruit bat is an important seed disperser and also a plant pollinator. It is able to retain viable seeds in gut for more than 12 hours, allowing long-distance seed disperser (Shilton et al. 1999). The mode of seed dispersal includes defecating or dropping seeds in flight, dispersing seeds over large areas (Tan et al, 1998). One study showed that this species of bats were able to disperse half of tree's original seed within a range of approximately 20 to 30m (Reiter et al. 2006) .
In Malaysia, the Ficus fistulosa is a key component in the diet of the lesser dog-faced fruit bat. So, the seeds of the Ficus fistulosa are mainly dispersed by the lesser dog-faced fruit bat with high percentage of germination (96 to 100% depending on the condition of seed after feeding) (Hodgkison et al, 2003). Hence there is a mutualistic relationship between the lesser dog-faced fruit bat and the Ficus fistulosa. In Singapore, a similar mutualistic relationship is seen between the lesser dog-faced fruit bat and the tiup tiup (Adinandra dumosa) (Phua et al. 1989).
In general, bats can also serve as indicator species to monitor biodiversity. More information can be obtained here.
The lesser dog-faced fruit bat is categorised as of "least concern" because of its extensive presence in Southeast Asia and India, its ability to thrive in a diverse range of habitats (even in people's houses!) and its presumed large population. Also, its population numbers are not declining rapidly enough to qualify as being threatened. The slow decline in population numbers is primarily due to habitat loss from deforestation for timber and oil palm plantations. Even worse, conservation efforts for the lesser dog-faced fruit bat is poor as it is often seen as crop pests due to damage to fruit crops.
However, there are conservation programmes present for fruit bats around the world. They include scientific and charitable groups which help for bat monitoring, and local educational programmes. One example is bat cloud.
6A. Type Specimen
Definition of Type specimen: A type specimen is a physical specimen in which the scientific name of every taxon is based on.
The type specimen for this species is collected in Dewei river in Borneo, and described by Muller in 1938. However, the current location of the type specimen is unknown.
Species level phylogeny of bats
|Image from Tree of Life|
|(Bastian et al. 2003)|
Status of Cynopterus brachyotis as a single species
The current state of Cynopterus brachyotis is uncertain due to variations of bats, namely in size and colour, that is present in the species.
|(Campbell et al. 2004)|
Four lineages from India, Myanmar, Sulawesi and Philippines are well defined geographically. However, two lineages in Malaysia, Sunda and Forest are sympatric and ecologically distinct. Hence, these two lineages are thus further investigated.
|(Abdullah et al. 2006)|
In addition, the type specimen of Cynopterus brachyotis is clustered together with the large form of Cynopterus brachyotis.
In support of this findings, micro-satellite data also showed the presence of two lineages in Southern Thailand, Malaysia and Borneo (Fong PH. 2011).
|(Jayaraj et al. 2012)|
|Morphological measurements(Jayaraj et al. 2012)|
Another model was also done to differentiate the fruit bats of C. horsfieldii, Sunda and Forest lineages in Malaysia. As the forearm length is usually employed to distinguish these two lineages during field studies, it will not have high accuracy due to variations in forearm length measurements. Thus, this study (Jayaraj et al. 2012) tried to develop a list of features to attempt to classify the lineages for both field studies and museum specimens. These features include skull, dental and external measurements. UGPMA cluster analysis of 28 characters on morphological measurements showed separate clades of C. horsfieldii, C.cf.brachyotis Forest and Cynopterus brachyotis.
In conclusion, more research has to be done to further identify and correctly separate the lineages within Cynopterus brachyotis species. Conservation has to be planned to ensure that all six form do not go extinct. The two lineages Indian and Forest are restricted within the forest habitat, which is becoming increasingly fragmented due to forest loss, thus having higher risks of being endangered.
6C. Gene Sequence
There are 25 barcode sequences of Cynopterus brachyotis from BOLD and GenBank. Example of these sequences include COX1 and cytochrome B. More information can be obtained here.
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Bastian T. Severo, Jr., Kazuaki Tanaka, Rea Victoria P. Anunciado, Nelson G. Natural, Augusto C. Sumalde, and Takao Namikawa. 2003. Phylogenetic relationships among megachiropteran species from the two major islands of the Philippines, deduced from DNA sequences of the cytochrome b gene. Can. J. Zool. 79: 1671 - 1677.
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Philip H. Krutzsch. 1959. Variation in the Os Penis of Tropical Fruit Bats. Journal of Mammalogy , Vol. 40, No. 3 (Aug., 1959), pp. 387-392
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Shilton L. A, Altringham J. D, Compton S. G, Whittaker R. J. 1999. Old World fruit bats can be long-distance seed disperser through extended retention of viable seeds in the gut. Proc Biol Sci. 266 (1416): 219.
Tan K. H , A. Zubaid & T.H. Kunz. 1997. Tent construction and socialorganization in Cynopterus brachyotis (Muller) (Chiroptera: Pteropodidae) in Peninsular Malaysia,Journal of Natural History, 31:11, 1605-1621
Tan, K.H., Zubaid, A. and Kunz, T.H. 1998. Food habits of Cynopterus brachyotis in Peninsular Malaysia. Journal of Tropical Ecology, 14: 299 - 307.
Tan K. H, A. Zubaid, T. H. Kunz. 2000. Fruit dispersal by Lesser Dog-faced Fruit Bat. Malayan Natural Journal, 54:1, 57-62.
This page was authored by Tan Xiao Rui Joanna
Last curated in 2013