Thyroptera tricolorSpix's disk-winged bat

Geographic Range

Thyroptera tricolor is found only in the Americas. It lives in tropical forests ranging from southern Mexico to the southeastern edge of Brazil.

Habitat

Physical Description

These bats are reddish brown colored dorsally and cream underneath. Along their sides their color is usually intermediate, resulting in the specific name tricolor.

They have long snouts and pointed ears with a tragus present. These bats also have "warts" on their noses, and it has been hypothesized that these "warts" are used as an extra sense organ. They do not have noseleafs.

At the base of their thumbs and ankles this species has disk-shaped suction cups that they use to cling to the inside of the leaves in which they roost. The suction cups are controlled by fine muscles, and one of these disks is strong enough to support the bat's entire weight. Their tails extend beyond the end of the uropagium.

  • Range mass
    4 to 5 g
    0.14 to 0.18 oz
  • Range length
    27 to 38 mm
    1.06 to 1.50 in
  • Average wingspan
    225 mm
    8.86 in

Reproduction

After young are born, they nurse, and are unable to fly for one month. During this time they either stay in the roosts or cling to their mothers when they go out to feed. After the month is over they learn to fly, although sometimes stay besides their mother for a little while longer. Mothers may fly around with their offspring clinging to them, even when their offspring constitute up to ~46% of their weight. These bats are polygynous and fertilization is sexual and internal. These bats breed twice annually. Pregnant females were observed in Costa Rica in August.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 to 1

Behavior

This species roosts in the young, partly unfurled leaves of trees of the genus Heliconia.

They roost in colonies of about 6, composed of one or more adult males, several mature females and several juveniles of both sexes.

These bats change roosts every day or so, because the tree leaves mature and unfurl. The individuals in a colony usually stay together and all move together to new location when their leaf roost opens up.

This type of bat is unique in that it roosts with its head up, and holds on with its suction cups to the sides of the leaf.

When these bats are caught and put in a cage, even though there is nothing for their suction cups to cling to, they still prefer to hang right side up by hanging by their thumb-claws.

Communication and Perception

Food Habits

This species is an insectivore. It has been found to feed on beetles and flies. It consumes around 1 gram of insects in a night.

  • Animal Foods
  • insects

Predation

Since this species roosts in curled leaves, predators do not usually notice them. Another anti-predator adaptation is roosting with heads up, this makes it easier for the bats to fly away easily at the slightest sign of danger.

Economic Importance for Humans: Positive

Insect population control.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

None.

Conservation Status

They have a patchy distribution, because there are only so many unfurled leaves in any one place, but their condition is stable.

Other Comments

These bats are known to lick their suction cups in order for them adhere better to their leaf-roosts or to glass when placed in a container to observe. They also have special sweat glands in their suction cups which help them adhere to surfaces better.

Contributors

Dorothy Blair (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

colonial

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.

endothermic

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

insectivore

An animal that eats mainly insects or spiders.

motile

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.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

rainforest

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.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

"Animal Diversity Web" (On-line). Accessed October 11,2001 at http://animaldiversity.ummz.umich.edu/chordata/mammalia/chiroptera/thyropteridae.html.

Fenton, M., J. Rydell, M. Vonhof, J. Eklof, W. Lancaster. "Constant-frequency and frequency-modulated components in the" (On-line). Accessed October 11,2001 at http://www.nrc.ca/cisti/journals/cjz/z99-168.html.

Graham, G. 1994. Bats of the World. New York: St. Martin's Press.

Nowak, R. 1997. "Walker's Mammals of the World" (On-line). Accessed November 15, 2001 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiroptera/chiroptera.thyropteridae.thyroptera.html.

Vaughan,, T., J. Ryan, N. Czaplewski. 2000. Mammalogy. Saunders College Publishing.

Wilson, D., J. Findley. 1977. Thryoptera tricolor. Mammalian Species, 71: 1-3.

Wilson, D. 1997. Bats In Question. Hong Kong: South China Printing Co..