Chiroptera - Bats!
The second largest order of mammals. Over 1,120 species.
19 families; we will only cover a few.
Found worldwide (except Antarctica and a few odd islands).
Essentially bats need no description - everyone recognizes them fairly quickly.
Relationship is a bit uncertain; they've been associated with lots of different groups including rodents.
(German name for bats is literally “flying mouse”, and even the English name “bat” seems to be related to mice.)
Generally agreed to belong to a group/clade of mammals that includes carnivores, ungulates and some others (see text).
Wings in bats are made up of “finger” bones, but do provide a typical airfoil shape:
Air takes longer to cover the dorsal side, reducing pressure, causing lift.
(Birds are similar in this regard).
However, bats are much more maneuverable than birds (in general).
Flight seems to have evolved before echolocation.
Various membranes do have names; you should be familiar with the uropatagium at a minimum (the membrane that stretches from the legs to the tail).
This is also often used to catch insects.
Echolocation:
The ability to use sound waves to determine where things are in the environment.
Bat will scream at loud volumes (be happy we can't hear it).
Echo provides bats with distance information, location, direction, speed, etc. of any objects it encounters.
Bats have no problem maneuvering in complete darkness.
(Bats are NOT blind!)
We may say a lot more about echolocation later in the semester, if we have time. Earliest known bat is from the early Eocene - found in Wyoming and India.
Wings were good enough it could probably fly.
It is thought bats evolved earlier, but there is no evidence so far.
Disease and bats:
Currently white nose syndrome is decimating bat populations, particularly in the Northeast.
Disease has been tracked to a fungus that grows on bats while hibernating.
(Immune system seems to fight off the fungus when the bat is not hibernating).
Is moving slowly south and west.
To date has killed over a million bats; mortality rates are 90 - 100%.
On the downside, bats are also a large reservoir for rabies in the U.S.
Estimates are that only 0.5% of bats carry rabies in endemic areas.
But there are a lot of bats.
Is often transmitted to humans (bats flying erratically, biting people, etc.).
Sometimes people don't notice they've been bit.
Incidentally, rabies can be contracted through airborne means, but only when concentrations of virus are unusually high (e.g., cave with lots (LOTS) of bat droppings).
In Europe, rabies is no longer endemic, so this has become a lot less of a problem.
We could spend a lot of time on this, but let's get started on going through the Chiroptera:
Note: let's not worry about dental formulas here; they're too variable.
Bats are divided into two groups:
Megachiroptera (big bats or megabats)
Fruit bats - with a few exceptions do not echolocate.
Microchiroptera (small bats or microbats) All other bats - echolocate.
Family Pteropodidae
Fruit bats, flying foxes. About 186 species.
Most eat fruit, nectar, or pollen.
Some are important pollinators.
Some can be important pest species (eat/destroy fruit crops).
Are much larger than bats around here.
Largest gets to about 1.2 m in wingspan.
(In the Seychelles one used to be able to eat bat curry).
Two genera (Stenonycteris and Rousettus) use tongue-click echolocation.
Not as refined as the other group of bats.
Face is longer, fox like, usually without protuberances and such.
Families Hipposideridae & Rhinolophidae
Old word leaf nosed bats and horseshoe bats.
Named after nose decorations that help emit sounds.
Until recently, were considered a single family (two subfamilies).
Well treat them together since they are very similar.
Can keep mouth closed during echolocation (sounds emitted through nostrils).
Some species can use very high frequency echolocation calls that are not (yet) detected by moths.
Some Rhinolphids are known for picking arthropods off leaves or ground.
Hipposiderids are more tropical, Rhinolophids extend into Europe.
Most roost in caves, but some will roost in trees or even houses.
Family Noctilionidae
Fish eating bats. Two species.
Can detect ripples in the water caused by fish.
Reverse foot (claws pointing forward), grab fish, bring it up to the face and grab it with their teeth.
Also eat insects.
Family Phyllostomidae
Leaf-nosed bats (sometimes Old World leaf nosed bats).
Leaf like structure on the nose (helps amplify/direct sound).
Large, diverse group, with 161 species.
Includes insect eaters, frog eaters, vertebrate eaters, nectar and plant eaters, etc.
Also includes vampire bats! E.g. Desmodus rotundus.
Vampyrum spectrum, Spectral bat is the largest bat in the new world and eats small vertebrates including birds, mammals, amphibians and reptiles.
Nectar feeding is quite common, and some bats even have special adaptations to help them eat pollen as well.
Oddest group is probably the vampire bates (subfamily Desmodontidae).
Desmodus rotundus usually lands next to “victim”, climbs onto leg or or elsewhere that's accessible and makes small incision with teeth.
Anticoagulants are used to prevent clotting.
In some areas are major problem as many bats will feed on livestock night after night.
Will occasionally feed on humans.
Have also been known to transmit rabies.
Several species get into the extreme southwestern U.S.
Family Molossidae
Free tailed bats.
Tail extends past end of uropatagium. World wide distribution.
These are the ones that are responsible for the spectacular bat flights in Carlsbad, Austin, and elsewhere.
Mexican free-tailed bats (Tadarida brasiliensis).
Cover most of southeast U.S., even make it into Virginia.
Several other species occur in the U.S., but are fairly uncommon.
Fly faster than most other species of bat (tail can be used aerodynamically).
Family Vespertilionidae
Vesper bats (evening bats).
Largest group of bats, with close to 400 species.
Includes most common bats around here.
World-wide distribution, including many ocean islands.
Generally “plain” bats, with not many odd protrusions.
Most chase down insects while in flight, but a few will go for insects or other arthropods on the ground (or on leaves).
Roost in a wide variety of places.
Depending on the species, anything from caves, trees, to houses.
Most temperate zone species hibernate.
Text mentions that they do well in urban settings (often found in attics and elsewhere).
Bat houses...