Bat

Batsbelonging to the order Chiropteraare the only mammals that can fly. Capable of sustained flightbats flap their long spread-out digits covered with a thin membranous structure (patagium) for flying. They are typically more maneuverable than birdsand this abilitycombined with their capability to navigate using an acoustic orientation methodhas made them a highly populous order.

Physical Description and Appearance

Size: Their size varies depending on the species. Kitti’s hog-nosed bat is the smallest bat species with a length of 1.14-1.34 in (29-34 mm) and a wingspan of 5.91 in (15 cm). The golden-crowned flying fox is one of the largest bats with a forearm length of 8.5 in (215 mm) and a wingspan of 4.9-5.6 ft (1.5-1.7 m).

Weight: The smallest Kitti’s hog-nosed bat weighs about 0.07-0.09 oz (2-2.6 g) while the giant golden-crowned flying fox has an average weight of 4 lb (1.6 kg).

Color: They are usually black or brown, but may have orangewhiteredor gray coloration. Certain types like the spotted bats possess white facial markings.

Head: The shape of their head varies by species with the megabats having larger eye socketssmaller earsand longer snoutsgiving them a dog-like appearance. Microbat species like vampire bats possess reduced snouts for accommodating large canines and incisors.

Dentition: Insect-eating bats possess 38 teethwhile blood-sucking vampire bats have 20. Bats feeding on hard-shelled insects are characterized by longer canines and robust lower jaws. Nectar-feeding bats have long canines and reduced cheek-teethwhile fruit-eating bats have cheek-teeth cusps adapted for crushing.

Wings: Bats have much thinner wings, consisting of more bones as compared to the wings of birds. The wing surface has touch-sensitive receptorswhile the patagium or wing membrane contains elastic fibersnervesblood vesselsconnective tissuesand muscles.

Distribution

Aside from the Arcticthe Antarcticand some isolated oceanic islandsbats are distributed throughout the worldbeing abundant in the tropics. About 45 bat species are found in the USwhile approximately 100 species exist in West Africa.

What kind of Habitats do Bats live in

Bats can live in diverse habitats depending on the seasonranging from deserts to mountains and seasides. They need suitable roostswhich are found in crevices, foliagehollowsand human-made structures. Megabats typically roost in trees.

How long do they live

In the wildthe average lifespan of bats is less than 20 years. Six speciesincluding the Indian flying foxgreater horseshoe batlesser mouse-eared batBrandt’s batlittle brown batand brown long-eared bathave been found to live for more than 30 years in the wild.

In 2006scientists found a tiny bat in Siberiawhich was documented to be the longest-livinghaving survived for 41 years.

What do they eat

Most microbats are insectivores and feed on fliesmosquitoesmothsbeetles, cricketsgrasshoppersbeestermiteswaspscaddisfliesand mayflies. Megabats are usually frugivores that eat fruitspollensand nectar. Insectivorous bats consume more than 120% of their weightwhereas frugivorous bats eat over two times their body weight. The large amounts of food consumed make up for the energy lost through a flight.

Some bat speciessuch as the fringe-lipped bat hunts frogsgreater noctule bat feeds upon birdsand greater bulldog bat eats fish. Several species like the common hairy-legged and white-winged vampire bats feed on the blood of mammals and birds.

Behavior

• Microbats
  are generally nocturnal mammalswhile most megabats are diurnal or
  crepuscular.
• Bats
  use their larynx for producing ultrasonic soundsemitting through the mouth
  and occasionally the nosethereby creating echoes. The outgoing pulse is
  compared with the returning echoes to create detailed images of the
  surroundingsallowing them to detect and identify their prey.
• In
  temperate regionssome microbat species migrate several hundred kilometers to
  their winter hibernation dens. Others pass into a state of decreased activity (torpor)
  during the winter months. Some bats retreat to caves where they hibernate for
  up to six months.
• Some
  species like the Mexican free-tailed bats live in colonieswhile others such
  as the silver-haired bats lead a solitary life.
• They
  emit low-frequency calls for attracting mates and finding roost partners to
  defend resources.
• When
  not flyingthey roost by hanging upside down from the feet. Most bats are
  capable of crawling awkwardly on the ground.

• Bats have a better ability to conduct heat than other mammals. Their wings consist of blood vessels that loose heat when extended. For this reasonthey wrap the wings around their bodies at resttrapping a layer of air for insulation.

Adaptations

• Their
  wing membranes are so thin and delicate that they help them to maneuver
  accurately and fly with less drag and more lift.
• The
  leading edges of the wings of pollen- and nectar-eating bats are so sharp that
  they create vorticesproviding lift when flying.
• They
  have ankle joints that can be bentallowing the trailing edge of their wings
  to curve downwardsthereby permitting them to clamber up and hang on trees.
  Bats also have tendons for locking their feet when roosting.
• Bats
  have a specialized respiratory system for coping with the demands of their
  energetically taxing flightwhich requires a continuous supply of oxygen.
• Their
  ears are sensitive to the slightest of noises made by mothstymbalate insects,
  and ground-dwelling centipedes and earwigs. The ridges located on the inner
  surface of their ears help them focus on echolocation signals and listen for
  other sounds made by the prey.
• Species
  like tube-lipped nectar bats have longextensible tongues that are covered
  with fine bristleshelping them to feed on the nectar of flowering plants.

Reproduction and Mating

Bats may have polygynous (males have multiple female partners)monogamous (males have one mate at a time)and promiscuous (both males and females have multiple partners) mating systems depending on the species. Pipistrellevampireand noctule bats are polygynouswhile the little brown and Mexican free-tailed bats are promiscuousand the spectral and yellow-winged bats are monogamous.

In temperate regionsbats mate during late summer or early autumnwhile tropical bats copulate in the dry season. To prevent other males from matingmales leave behind a vaginal plug after copulation. Males of hibernating species mate with females in a dormant state.

Females of some bat species exhibit delayed fertilizationmeaning the sperm is deposited in their reproductive tractand fertilization takes place in spring several months after mating. Other species have delayed implantationwhich means that the egg remains free in the mother’s reproductive tractand the birth of young is delayed until conditions become favorable to care for the offspring.

Temperate-living bats in the northern and southern hemispheres give birth in May-June and November-Decemberrespectivelywhile tropical species produce their offspring at the start of the rainy season. Females usually give birth to one offspring per litter. The pup weighs about 40 percent of its mother’s weight at birth. Young bats are weaned in about 80 days.

Conservation

In countries across AsiaAfricaand the Pacificbats are eaten or hunted for food. Pressure damage caused by wind turbines also kills bats. Organizations like Bat Conservation International strive towards increasing awareness regarding the ecological roles played and the threats faced by bats.

In the UKthe Wildlife and Countryside Acts protect all bat specieswhich means harming them in any way is a punishable offense. The Wildlife Protection Ordinance 1998 has also been implemented in SarawakMalaysiato protect all bats from being hunted or eaten.

Bat-FAQs

1. Are bats blind?

Although no bats are blindmost microbat species have small and poorly-developed eyes, leading to poor clarity. They can detect low levels of lightwhile some microbats can even detect UV light. Megabatson the other handhave good eyesight that is adapted to daylight and night visions.

2. Do bats hibernate?

Some species, including Indiana bateastern red batsilver-haired batand little brown bat hibernate in places like minescavesand rock crevices with ideal humidity and temperature.

3. Are bats rodents?

No. Bats are not even related to rodents.

4. Are bats dangerous?

Some bats can be harmful to humans since they may carry many infectious bacteria and viruses, including rabiesNipahEbolaand coronaviruses.

5. Do bats lay eggs?

No

6. What is a baby bat called?

A pup

7. What is a group of bats called?

A colony

8. What predators may eat bats?

Birds of prey like hawksowlsand falconsalongside terrestrial predators such as cats and snakesmay hunt and feed on bats.

Interesting Facts

• Nectar-feeding bats act as pollinatorsand more than 500 flowering plants and fruit trees depend on bat pollination for the dispersal of pollens and seeds.
• Microbats use magnetoreceptionthe sensitivity to the Earth’s magnetic fieldfor differentiating north from south. It is particularly useful in long-distance travel.
• In European culturesbats symbolize darknesswitchcraftdeathand evilwhile the Native Americans like the CherokeeApacheand Creek consider the bat as a trickster spirit.
• Insectivorous bats are helpful to farmers since they lessen the population of agricultural pests by reducing the use of pesticides.
• Bat dung or guanobeing rich in nitrogenpotassiumand phosphateserves as an effective fertilizer.