Order Chiroptera

Common name bats
# of Suborders 2 (Megachiroptera, Microchiroptera)
# of Genera 168
# of Species >920
Distribution worldwide, except polar regions and a few oceanic islands

I. General characteristics

  1. Forelimbs modified as wings (the only true flying mammals)

    1. Radius (forearm), metacarpals (hand) and phalanges (fingers) #2-#5 greatly elongated
    2. Enclosed in a web ( patagium , 2 layers of skin, muscle, connective tissue)
    3. Claws on pollex and all hind digits
    4. Keel on sternum

  1. Ecology and behavior

    1. Widely varied diets

      1. Insects
      2. Fruit, nectar, pollen
      3. Fish and small vertebrates
      4. Blood

    1. Nocturnal
    2. Gregarious, roost in caves and hollow trees
    3. Hang upside down
      1. Easier to take off? video (at 2:50)
      2. Leg bones too delicate to support body weight?
      3. Hip bones reversed to allow control of uropatagium? video (at 1:00)

    4. Reproductive variants common

    1. Ecological importance

      1. Fruit bats: plant dispersal
      2. Pollen feeders: pollinate plants
      3. Insect eaters: insect control

    1. Abundance may be due to

      1. Mobility
      2. Ability to echolocate
      3. Ability to hibernate

    II. Two suborders (Table 12.1)

    Megachiroptera Microchiroptera
    1 family (Pteropodidae) 17 families
    Generally large Generally smaller
    Big eyes, little ears with no tragus Little eyes, big ears with tragus often well-developed
    No nose or facial ornamentation Nose and facial ornamentation often present
    Tail and uropatagium usually absent Tail and uropatagium often present
    Unmodified cervical vertebrae; head held ventrally during roosting Modified cervical vertebrae; head held dorsally during roosting
    Navigate using vision (only 1 species echolocates) Navigate using echolocation
    Don't hibernate or undergo torpor Many hibernate or undergo torpor
    Old World Worldwide

    A. Evolution and phylogenetics

    1. Ancestry is murky

      1. Earliest fossil bat Icaronycteris (60 mya) (Fig. 12.10)
      2. Fully formed wings
      3. Skull morphology indicates ability to echolocate

    1. Proposed phylogenies

      1. Based on features of the visual system (Pettigrew hypothesis)

      2. Based on genetic and morphological data
      3. Based on more recent genetic data (e.g., Murphy et al 2001), leading to new proposed suborders (Yinpterochiroptera and Yangochiroptera)

      4. Based on a very recent analysis of a single mitochondrial gene (Agnarsson et al. 2011)

      B. Megachiroptera

      1. Family Pteropodidae

      Common name fruit bats
      Distribution Africa, S.E. Asia (tropical)

      1. General characteristics

        1. Tend to be large (up to 1.5 kg)
        2. Fox-like faces (long rostrum)
        3. Simple nose and ears
        4. Navigate using vision
        5. Wrap themselves in their wings while roosting
        6. Low reproductive rate

      C. Microchiroptera

      1. Echolocation using ultrasound (all species)

        1. How it works
          Biosonar demonstration
          video of prey capture

        2. Types (Fig. 12.6)

          1) Frequency modulated (FM)
          2) Constant frequency (CF)

        1. Associated morphological specializations

          1) nose leafs
          2) complex faces
          3) big ears with tragus
          4) alterations in cranial structure (Fig. 12.15)

          5) middle ear specializations

      1. Family Phyllostomidae

        1. "Leaf-nosed" bats
        2. Most diverse family

      1. Family Desmodontidae

        1. Sometimes included in Phyllostomidae
        2. Vampire bats (only mammalian blood feeder)

      1. Family Vespertillionidae

        1. Largest family (33 genera, 310 species)
        2. Worldwide distribution
        3. Plain faces
        4. Predominantly insectivorous
        5. Often commensal with humans
        6. Diheterothermic (70% of species)
        7. Many species hibernate

      1. Family Molossidae

        1. "Free-tailed" bats
        2. Colonial
        3. Individual recognition calls to reunite mother and pup

      1. Feeding specializations

        1. Blood

          1) heat sensing pits in nose leaf
          2) specialized incisors
          3) saliva contains anticoagulant
          4) specialized kidneys

        1. Nectar

          1) long snout
          2) long tongues
          3) specialized facial and body hairs to trap pollen
          4) pollen is their primary source of protein

        1. Fish

          1) echolocate on water surface
          2) catches fish with feet