BAT DIVERSITY 2

FEEDING
1. Brown Long-Eared Bat: eats large moths etc from surfaces (gleaning), adapted to taking animals which weigh a large proportion of own body weight: just a small step to taking small mammals
  1. Australian Ghost Bat (false vampire): Small evo step, can feed on rodents and small marsupials, which is safer to do than taking bigger scorpions
2. ~ 12 carnivorous bat species: feeding on birds (Greater Noctule Bat in autumn when birds migrate), fish (Fish-eating bat and Fisherman's bat), mammals (Hoary bat), frogs (frog-eating bat, fringe-lipped bat)
  1. Carnivorous Bats: Echolocate and so have elaborate nose shapes and big ears etc. BUT also have large eyes at FRONT of head: binocular vision, allowing predator to estimate distance better, usually has big teeth too for dealing with prey, skull size dependent upon food source,
  2. A few species have become very specialized such as fish and frog-eating bats Probably the most specialized of all are the three species of true vampire bats that eat only blood, and have physiological adaptations to this lifestyle
3. Epauletted Bat: flying after taking a meal is energetically costly. these have evolved to squeeze juice from fruit and remove unwanted pulp: adaptation to feed without flying costs - Important for ecological reasons: 2 ways of seed dispersal, through rejected pulp and through normal route - bats vs. birds importance in dispersal in tropical forests
4. Steps from taking insects - fish - mammals: INCREASE IN PREY SIZE
  1. Daubenton's Bat: -aerial insectivore - can also scoop insects (especially emerging insects/larvae) from surface of water - scoop up with feet pr tail membrane which is adapted to this purpose
    1. Fisherman's Bat: - S and C America - can eat small fish using long claws - using echolocation to locate protruding fin or ripples on surface of water - GAFF: targeting SPECIFIC insects/fish, but when prey in high density they will TRAWL - Mouth open during flight for EL - 'bulldog bat': skin flaps help to grip fish
5. Lots of bats feed on the ground: ground predators - hover close to ground and drop onto prey. e.g. Pallid bat: Arizona - eats scorpions, large centipedes etc., adapted physiology - immune to toxins in the sting and when eating
ROOSTING
1. Only a small minority actually roost in caves
2. MOST roost in trees or out in the open, particularly tropical forest bats
  1. But also some N. American/Canadain species do: e.g. Hoary Bat: looks like a bear - furry because lives in cold climate - lives in coniferous forest - tail is furry too (usually naked) to warm the feet
3. SOLITARY vs. FAMILY vs. COLONY
  1. Spectrum: from solitary bats to those living in huge colonies in caves
    1. Bracken Caves: 4 million Brazilian Free-Tailed Bats
    2. Two extremes: hiding away in huge colonies to open roosting along

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BAT DIVERSITY 2

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	Erstellt von shannonle vor fast 11 Jahre