Problems

Lecture 1: Diversity

1.  What family of bats includes species that feed on vertebrate prey in Africa and Asia?  Name a representative species.

2. What family of bats includes species that feed on vertebrate prey in Central and South America? Name a representative species.

3.  What family of bats primarily orients by vision? Name a representative species.

4.  What family(s) of bats includes species that hibernate? Name a representative species.

5. What family(s) of bats includes species that emit constant frequency echolocation pulses? Name a representative species.

Lecture 2: Evolution

6.  What is the age of the oldest fossil bat?  What evidence was used to arrive at this age?

7.  What evidence supports two evolutionary origins of bats?  What evidence supports a single evolutionary origin for bats?

8.  Why are some families of bats found on all of the major continents of the world while other families are restricted to a single continent, such as South America. 

9.  What distribution pattern would you expect the family containing the common ancestor of all bats to have?  Why?

10.  How many different orders of mammals exhibit gliding flight?  Give representative examples.

11.  Which is more likely to have evolved first: echolocation or flight?  Explain your answer.

Lectures 3 and 4: Echolocation

12. What is the wavelength of a 40,000 Hz tone in air?

13.  How would an FM bat know that it was approaching a wall rather than an insect 5 m away?

14.  How much greater is the sound pressure produced by an echolocating bat, which emits 100 dB calls at 1 m, than a sparrow, which produces 70 dB calls at 1 m?

15.  Why do FM bats reduce pulse duration to avoid pulse-echo overlap as they approach a target?

16. Amazon river dolphins hunt fish by echolocation.  What frequency of sound would you expect them to use if the fish they capture are no more than 1.5 m in length?

17. If you captured a new species of bat, recorded its echolocation call and discovered that it produced a 300 kHz call, what could you predict about a) where it must forage relative to vegetation, b) the size of prey it must eat, and c) the likelihood that it uses echolocation calls for social communication?  Explain your answers.

18.  Oilbirds produce clicks in damp caves and use the echoes to orient and avoid obstacles.  If an oilbird has the same auditory sensitivity as a human, i.e. can hear sound above 0 dB, how far away could it detect an obstacle if the clicks register 78 dB 1 m from the bird?

Lecture 5: Hearing

19. If you dissected the ear of a mammal with poor high frequency hearing, like us, and compared it to a mammal with excellent high frequency hearing, like a bat, what differences would you expect to see in the cochlea?

20.  What would happen to our hearing if the bones in the middle ear were removed and the oval window of the cochlea became the same as our eardrum?

21.  Describe three adaptations that enable horseshoe bats to have extremely good hearing at a narrow range of high frequencies.

22.  Bats often get in fights that cause damage to their outer ears (pinna).  What effects on the bats hearing will loss of its pinna have?

23. Explain how bats that use constant frequency echolocation pulses extract information about the velocity of their prey from pulse-echo information.  How do they determine distance?

24.  How do bats that live in large colonies inside caves avoid being confused by the pulses and echoes of other individuals as they fly in and out of the cave?


Lecture 6: Flight

25.  Explain why bats can fly with greater maneuverability than most birds. 

26.  Why is hovering flight usually more expensive than horizontal flight?

27.  Draw a picture of an aerofoil and explain how lift is generated.

28.  What type of bat do you expect could create thrust on an upstroke – a bat with high aspect ratio or low aspect ratio?  Explain your answer.

29.  Provide an explanation for why flight has not evolved more than once among mammals.

30.  A new species of bat has been recorded hunting by echolocation high above the rainforest in southeast Asia.  Based solely on this information predict what the species looks like, i.e. size and shape of wings, what type of echolocation calls it uses, and what family it is from.

Lecture 7: Energetics and torpor

31.  Explain why small animals need to have higher metabolic rates than large animals.

32.  Explain why oxygen consumption measures energy utilization for an animal.

33.  Graph daily oxygen consumption for a temperate insectivorous bat over the course of a year.  Contrast males and females and explain when the energy demands are likely to differ between the sexes.

34.  Describe three behavioral responses that bats use to avoid severe temperature fluctations.  Provide an example for each case.

35.  What does BAT do and it what ways is it an adaptation?

36.  What evidence has been used to infer that bats have a circadian rhythym?

37.  Provide a hypothesis for how migratory bats determine the appropriate direction to travel.  How might you test this hypothesis?

Lecture 8: Life history and longevity

38.  Explain what is meant by Type I, II and III survivorship curves.  Which curve most closely resembles bat survivorship?

39.  Explain the concept of reproductive value.  At what age is maximum reproductive value for a human?

40.  From an evolutionary perspective, explain why we age.

41.  What factors influence longevity in bats?  For each factor, explain why such an association would be expected as a consequence of evolution.

42.  What is free radical production and why is it believed to be related to maximum longevity in animals?

Lecture 9: Reproduction, mating and sperm competition

43.  Contrast reproduction in humans and a temperate bat, such as the little brown bat Myotis lucifugus.  In what ways are the sexes similar and different?  In your answer mention hormonal cycles, reproductive anatomy, mating, sperm storage, and timing of fertilization.

44.  Describe three mechanisms that bats use for controlling the time of parturition.  Give a species example to illustrate each case.

45.  Describe three different mating systems that have been described for bats and provide an example of a species that exhibits each type.

46.  What criteria define a lek? How does the home range size of males and females differ in species that form leks?

47. A new species of bat has been discovered in southeast Asia.  If male body size is twice that of females, what type of mating system would you predict this species likely exhibits?  If you subsequently discovered that males had much smaller testes than expected for their body size, would you change your prediction?  Why or why not?

Lecture 10: Communication

48. What factors are expected to influence the honesty of a communication signal?  Give an animal example to illustrate each of your cases.

49.  A famous population geneticist, J.B.S. Haldane supposedly said evolution should favor those willing to give their life in exchange for saving two brothers or eight cousins.  Explain how Haldane reached this conclusion.

50. Provide an evolutionary explanation, i.e. is advantageous to the individual, other than kin selection, to explain the occurrence of alarm calling by a group living bat when it is captured in a mistnet.

51.  Describe three mechanisms that are thought to be used by animals to recognize kinship.  For each mechanism, give an animal example that is consistent with that mechanism.

52.  Many people have described nonrandom and clustered departures of bats from roosts.  Give two alternative explanations for why this behavior might be expected.  What evidence could you collect that would allow you to distinguish between these alternatives?

53.  What type of social organization would you expect would favor food advertisement calls?  Why?  Are there any bats that might be candidates for such behavior?

Lecture 11: Ecology

54. Explain how the earth's orbit around the sun influences the occurrence of ice ages.

55. Why is the water off Ocean City much warmer than the water off the coast of San Francisco despite being the same distance from the equator?

56.  Where are rain forests found on earth?  What environmental factors are needed for rain forests to persist?

57.  Where is bat species diversity greatest?  Provide an explanation to account for latitudinal changes in species diversity in bats.

58.  Do you expect to find more species of bats on the island of Trinidad (about 20 km north of Venezuela) or Cuba (about 20 km south of the Florida keys)?  Use island biogeography theory to justify your prediction.

59. Explain the concept of niche partitioning.  Provide evidence from lecture or readings which supports niche partitioning in bats.

Lecture 12: Coevolution

60. Describe  two adaptations by insects to avoid bat predation and by bats to improve prey capture.

61.  What is the detection distance of most moths?  Describe typical behavior of a moth with ears when it detects low or high amplitude bat calls.

62.  Ears have evolved at least 19 times in insects.  Describe one type of insect ear and list four locations where ears are found on an insect's body.

63.  Give three reasons for why some moths produce ultrasound in response to bat calls.  Describe evidence, if it exists, that supports each hypothesis.

64. Assume that you visit the neotropics and encounter a flowering tree.  Describe five features that would indicate it is likely to be pollinated by bats.

65.  How would you characterize the type of coevolutionary relationship that likely exists between bats and the plants they pollinate or disperse, i.e. obligate and species specific or opportunistic and involving multiple species.  Explain your answer.

66.  Briefly describe the life cycle of a bat fly.  Does the distribution of bat fly species on bat species indicate that bat flies are transmitted vertically or horizontally?  Explain your answer.

Lecture 13: Bats and man

67. Briefly describe the life cycle of a rabies virus.  Does the distribution of rabies variants on mammal species indicate that the virus is transmitted vertically or horizontally?  Explain your answer.

68. Why is it recommended that people who work on bats should wear respirators in bat roosting areas?  What might happen if they didn't?

69.  What is the primary source of human rabies cases in the world?  in Latin America?  in the United States?

70.  What are the main factors causing bat population declines worldwide over the past 50 years.

71.  Provide a possible explanation for why bat-transmitted rabies has increased in frequency over the past 15 years in the United States.

72. Why are organochlorinated pesticides, such as DDT, so harmful to wildlife such as bats?

73.  What single factor is most likely to improve bat conservation?  Why?