Lesson Plan

Fruit Bats Are Our Friends

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Grade Level:
Second Grade-Third Grade
Biology: Animals, Conservation, Ecology, Environment, History, Wildlife Biology
45 minutes
Group Size:
Up to 24 (4-8 breakout groups)
National/State Standards:
Standard 7: Students examine organisms’ structures and functions for life processes, including growth and reproduction. (ASDOE Elementary Science Standards: Grade 2-3, pp. 26- 35)


Fruit bats are considered the only native mammal in American Samoa thus earning the right to be protected within the National Park of American Samoa. Local folklore casts a dark image on fruit bats, portraying them as sinister and devious creatures with connections to the spirit world. These superstitions undermine their ecological importance to the native tropical rainforest. Fruit bats help transfer pollen from one tree to another and are also important for seed dispersal.


Students will be able to:

1. Define the vocabulary term fruit bats.

2. Identify and explain the role of fruit bats in American Samoa's tropical rainforest ecosystem.

3. Learn about the role of the National Park of American Samoa in protecting fruit bats.



Large flying foxes, also known as fruit bats, are one of the more unusual animals in American Samoa, especially for visitors from areas where bats are small and rarely seen. Three species inhabit our islands – two large fruit bats (Pteropus samoensis, P. tonganus) and a small insect-eating bat (Emballonura semicaudata). These three are the only native mammals in the Samoan islands.

The two flying foxes are especially distinctive: they are renowned for being large (with a wing span up to 3 feet wide) and active both day and night. Pteropus samoensis (pe'a vao) is commonly called the Samoan flying fox. The other flying fox, Pteropus tonganus (pe'a fanua), has several common names such as the Insular, White-naped, White-necked or Tongan fruit bat. In American Samoa, flying foxes can be seen flying, soaring, feeding, or just hanging in trees. Individuals of the two species can seem to overlap in size (adults weigh 300-600 grams). When they consume fruits with small seeds, some seeds that get swallowed do not get digested but are carried and deposited away from the tree source. These seeds grow and become the lush green rainforest that covers American Samoa. They are also considered pollinators as they transfer pollen when they fly from tree to tree consuming nectar or fruits.

During the daytime, pe'a fanua form large roosting groups or colonies of hundreds to thousands of bats. These colonies are generally organized according to their reproductive status and may be composed of bachelor males, clusters of females defended by an adult male (suggesting a harem mating system), or groups of females and their young. In any case, individuals appear to be relatively “faithful” to their roosts, usually returning to their respective colonies following foraging flights.

But the pe'a vao does not do this. Instead, these bats usually roost singly on branches, or as pairs of males and females (suggesting a monogamous mating system), or as a female with its young. When roosting, pe'a vao males tend to hang from exposed or dead branches of trees on ridge tops while females roost in more covered positions on forest slopes.

The care and energy that both bat species put into their young is remarkable. Pregnancy lasts approximately 5 months in both species, and once the young are born, it takes at least another 3 months before they are weaned. Even after they are capable of flight, the young continue to receive parental care, perhaps until they reach adult size or become reproductively active themselves. We know this from observations of pairs of individuals seen to alight independently on the same tree and subsequently come together with one individual (presumably the juvenile) being wrapped up in the other's wings as they settle down to roost. Sightings of pregnant females and individuals carrying young in flight indicate that pe'a vao give birth mostly between April and June. Pe'a fanua births appear to occur year-round but are more common in January and June to August.

Although their name indicates that they are fruit-eaters, both species also eat nectar, pollen, leaves, and sap. They tend to consume only the “juice” of fruits and leaves. To do this, a bat will carefully chew on food (usually eating around large seeds), press the pulp against the roof of its mouth with its tongue, squeeze and suck in the juice, then spit out most of the pulp in pellets called “ejecta.” These ejecta are especially abundant under breadfruit trees ('ulu) where the bats have been feeding overnight. Among the splatter of mushy bits of the fruit, you can find these pellets of drier material that sometimes show tooth and palatal (roof of the mouth) impressions, much like a dental cast produced at a dentist’s clinic.

It may bother us that flying foxes eat some of the fruit that we grow for ourselves, but these bats are tireless workers that help maintain the health of our rainforest, and they are fun to watch.


1. Fruit bat puppet

2. Power point program
3. Crayons and/or markers
4. The Rat and the Bat and Other Short Stories by Pemerika L. Tauiliili

Handouts & Worksheets
1. Fruit Bat Illustration


Last updated: February 28, 2015