Philippine tomb bats (black-bearded tomb bats, found throughout much of south and southeast Asia and the Malay archipelago. Philippine tomb bats are found exclusively on the islands of the Philippines. (Corbet and Hill, 1992; Heaney, et al., 2002; Nowak, 1997)) are a subspecies of the widespread species,
- Other Geographic Terms
- island endemic
Philippine tomb bats inhabit a variety of areas, from rainforests to woodlands. They are often found in hilly forest country near water but they may roost in many places including tombs, caverns, caves, rock crevices, sea cliffs, and trees. They are also becoming common in urban areas, roosting in buildings and churches. The bats are very agile while crawling, and are able to cling to sheer rock surfaces. This enables them to live places where other bats may not. Also, they often roost in well-lit areas that other bats avoid. Philippine tomb bats are gregarious and their relatively large colonies have been recorded with up to 4,000 individuals. Typically, adult males stay within their defined "territory" on the wall, and groups of females roost around them. (Flannery, 1995; Lekagul, 1977; Nowak, 1997)
- Range elevation
- 0 to 150 m
- 0.00 to 492.13 ft
Philippine tomb bats have a head and body length between 62 and 100 mm, a tail length between 20 and 35 mm, and they weigh between 10 and 50 g. Their fur is white and tipped with pale brown to reddish-white. The fur on their underside is even lighter brown/tan to white. Their ears and membranes are thin and light colored, appearing white; the legs and feet of are covered with short fur. They have a simple muzzle, with no complex noseleaf. Their ears are short to moderate in length and have a short, rounded tragus. There is a well developed wing pouch that helps distinguish them from other Taphozous species. Juveniles are typically darker than adults. Adult males have a black "beard" of fur at the bottom of their jaw/top of their throat. This can make easily identifiable, but the beard does not always appear. New research indicates this beard reflects seasonal changes and may have a role in mating systems.
Philippine tomb bats are unlike other Taphozous species in that they do not have the glandular sac that characterizes others in the genus. Instead, they have small pores in place of the sacs that open into the throat.
The wings are long and narrow, contributing to fast, long flights to forage. Philippine tomb bats fly high and fast, picking insects out of the air. Their wings are not adapted to agile flight or hovering and so they do not glean prey off the ground or off of plants. Instead,catches flying insects by "netting" them with their flight membranes and eating them mid-air.
The tail of Philippine tomb bats penetrates the interfemoral membrane near the center and are exposed on the dorsal side; this gives them their nickname sac-winged bats. The dental formula is like other members of Emballonuridae: 2/3, 1/1, 2/2, 3/3. The first upper premolar is minute, and there is a large gap between the upper incisors. (Altringham, 1996; Lekagul, 1977; Nowak, 1997; Payne, 1985)
- Sexual Dimorphism
- sexes colored or patterned differently
- male more colorful
- Range mass
- 10 to 50 g
- 0.35 to 1.76 oz
- Range length
- 82 to 135 mm
- 3.23 to 5.31 in
- Range wingspan
- 50 to 75 mm
- 1.97 to 2.95 in
Male Philippine tomb bats are polygynous and will mate with multiple females. There is one mating season per year, from January to February. Female Philippine tomb bats mate with only one male and produce a single young during each mating season. During the mating season, it has been observed that small glands in adult males excrete a thick sticky substance that collects on their beards. Information on the exact nature and function of this excretion is not yet available. It is likely that this substance contains hormones/pheromones designed to help attract mates.
The mating system is characterized by resource defense polygyny. This mating system involves the male providing and defending resources essential to females. The primary resource male Philippine tomb bats defend are safe nesting sites. Since Philippine tomb bats often roost in large colonies of thousands of individuals, a safe nesting site is essential to the upbringing of young. The quality of the nesting site and the ability of a male bat to defend it determines his mating rank with females. Those males that are most successful at this resource defense are able to mate with the most and best females. (Lekagul, 1977; Nowak, 1997)
- Mating System
The mating season of Philippine tomb bats lasts from January to February. During this time, males mate with as many females as possible. Each female mates only until she is pregnant. The gestation period lasts 3 to 4 months, and a single young is born between April and May. This single offspring is nursed by the mother for 8 weeks. After this time, the young are able to feed for themselves and leave the mother forever. There is no paternal care provided by the males. Information on the age at which Philippine tomb bats reach sexual maturity is unavailable. (Lekagul, 1977; Payne, 1985)
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- Breeding interval
- Philippine tomb bats breed once yearly.
- Breeding season
- Breeding occurs in January and February.
- Average number of offspring
- Average gestation period
- 4 months
- Average weaning age
- 8 weeks
- Average time to independence
- 8 weeks
The parental investment found in Philippine tomb bats is provided exclusively by the mother. The mating system is polygynous, so a male may father multiple offspring. However, he will not provide and care for any of his young. The mother will provide nourishment/food, shelter, and protection for the young. Weaning will conclude about eight weeks after birth, and at this time the young will learn to catch insects and other prey on their own. Once the young are old enough to feed for themselves, they are on their own. (Flannery, 1995; Lekagul, 1977; Nowak, 1997)
Lifespan in Philippine tomb bats is not known, but it is likely that they live longer than ten years under ideal conditions. (Heaney, et al., 2002)
Philippine tomb bats are social members of Emballonuridae and roost in colonies of from 150 to 4,000 individuals. Males and females occupy different areas of roosting sites and each individual has a defined vertical territory. Philippine tomb bats remain in their roost relatively inactive until the same time everyday, around 20 to 25 minutes after sunset, when they the cave to feed.
Hunting territory is considerably larger than that of many other bat species. This is becausehunts high above the ground, traveling at high speeds.
Closely related species (T. longimanus) hibernate for short periods, but specific information for Philippine tomb bats is unavaiable. Seasonal hibernation is indicated by the accumulation of fat at certain periods of the year, but it is unconfirmed. (Lekagul, 1977; Nowak, 1997; Prater, 1965)
The size of the home range ofis unavailable.
Communication and Perception
Philippine tomb bats communicate and perceive their environment via echolocation. Though they have rather large and well-developed eyes, echolocation is the primary method that these bats use to locate, identify, and track prey as well as perceiving their environment and avoiding obstacles. By sending out short bursts of sonic and ultrasonic waves from their mouths, which then bounce off objects, these bats can efficiently move through their environment, even in the dark. There is new research that indicates that these bats also use echolocation to communicate with each other, but specific mechanisms are not yet known.
Detailed information on communication in Philippine tomb bats is unavailable. However, males are known to secrete a sticky substance during mating season which sticks to their beard. This substance likely contains pheromones or hormones, and so plays a role in chemical communication.
Although details are lacking, some tactile communication is undoubtedly of importance between mothers and their offspring, as well as between mates. (Altringham, 1996; Heaney, et al., 2002; Nowak, 1997; Schober, 1984)
- Other Communication Modes
Philippine tomb bats are insectivores, catching their prey while soaring fast and high above the canopy. Bats in the genus Taphozous forage at relatively high altitude and high speed, catching flying insects directly in their mouths, or by scooping them up with wing/tail membranes.
Philippine tomb bats cover more area while hunting, and do not concentrate on small areas like other bats. Philippine tomb bats, like other predators, follow their prey's movements to new hunting grounds. Seasonal changes in prey density also cause (Altringham, 1996; Heaney, et al., 2002; Nowak, 1997; Prater, 1965)to move to new hunting grounds.
- Animal Foods
Information on the specific predators is unavailable. Hawks and owls have been observed to prey on adult Philippine tomb bats and the vunerable young can fall victim to predatory birds, reptiles, mammals, and even large insects. Predation is reduced because they are most active at night and are able to avoid predators. Adults of Taphozous species are even harder to prey upon because they fly at such relatively high altitudes and speeds; generally only other flying animals can catch them. Philippine tomb bats are relatively light colored, but they forage around dusk when it is not yet completely dark.
- Anti-predator Adaptations
Philippine tomb bats and other bats play an invaluable role in the ecosystem. Insectivorous bats consume millions of pounds of insects every year, helping to stop the spread of disease and limit crop damage. (Heaney, et al., 2002; Lekagul, 1977; Nowak, 1997; Prater, 1965; Heaney, et al., 2002; Lekagul, 1977; Nowak, 1997; Prater, 1965; Heaney, et al., 2002; Lekagul, 1977; Nowak, 1997; Prater, 1965; Heaney, et al., 2002; Lekagul, 1977; Nowak, 1997; Prater, 1965)
Economic Importance for Humans: Positive
Farmers must deal with millions of dollars worth of crop damage per year, due to destructive insect species. Bats of the family Emballonuridae consume tons of insects per year, providing a natural solution to insect pest problems. (Altringham, 1996; Lekagul, 1977; Prater, 1965)
- Positive Impacts
- controls pest population
Economic Importance for Humans: Negative
- Negative Impacts
- carries human disease
- causes or carries domestic animal disease
Philippine tomb bats are not known to be threatened or endangered. They are not listed on any government or third-party watch list. (Nowak, 1997)
Nancy Shefferly (editor), Animal Diversity Web.
Arthur Wang (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
- bilateral symmetry
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
- causes or carries domestic animal disease
either directly causes, or indirectly transmits, a disease to a domestic animal
uses smells or other chemicals to communicate
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- female parental care
parental care is carried out by females
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly insects or spiders.
- island endemic
animals that live only on an island or set of islands.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
- native range
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
found in the oriental region of the world. In other words, India and southeast Asia.
chemicals released into air or water that are detected by and responded to by other animals of the same species
having more than one female as a mate at one time
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- seasonal breeding
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- sexual ornamentation
one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sound above the range of human hearing for either navigation or communication or both
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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Nowak, R. 1997. "Tomb bats" (On-line). Walker's Mammals of the World Online. Accessed March 31, 2004 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiroptera/chiroptera.emballonuridae.taphozous.html.
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Sedlock, J. 2001. Inventory of insectivorous bats on Mount Makiling, Philippines, using echolocation call signatures & a new tunnel trap. ACTA Chiropterologica, 3/2: 163-178.
Singh, U., A. Krishna. 2002. Seasonal Changes in Circulating Steroid Concentration and Their Correlation With the Ovarian Activity in the Female Indian Sheath-Tailed Bat, Taphozous longimanus. Journal of Experimental Zoology, 292: 384-392.