The Lion`s mane

The Lion`s mane

main objectives
1. 1. why do lions have manes?
2. 2. scientists think manes must have some specialised function because are unique to lions.
3. 3. determine if the mane function is male-male competition, or mate choice, or both.
4. 4. importance of mane characteristics (length and darkness)
5. 5. sexual selection and behavior.
6. 6. why don't all males have the same mane
methods
1. Scientists started with different ideas as a guide
  1. 1. the mane is sexual dimorphic
    1. theory sexual selection / selective traits
      1. characterisics evolve under the stress of competition for mates
  2. 2. the mane develops at puberty
  3. 3. is variable within and between populations
2. previous information
  1. sexual selected traits increase reproductive success
    1. 1. male-male competition
      1. armor
      2. weapons
    2. mate choice
      1. male condition
3. mane might function in 3 ways
  1. shield against injury
  2. fighting sign
  3. nutrition status
4. two hypotheses
  1. mane area as a target on fights and wounds will be found there
  2. wounds in mane are more fatal
5. photographic achieves- changes in mane
  1. iidentify ecological trends
6. behaviour among males and females by length and darkness
  1. Dummies
    1. life-sized toy lions
      1. 1. (short, dark mane)
      2. 2. (short, blond mane)
      3. 3. (long, dark mane)
      4. 4. (long, blond mane)
results
1. hypotheses
  1. eliminate the wounds that were not inflicted by other lions
    1. it didnt support the mane-as shield hypotheses
  2. wounds in mane area were not more lethal than in other parts of the body
2. photographic
  1. develop their mane under 1 year and during that time the main gains pigment until the color becomes more stable
3. Dummies
  1. females prefer dark manes
    1. manes acts as a signal to the lions
  2. males were sensitive to mane darkness, avoid the darker dummie
  3. male sensitive to mane length, avoided too
    1. mane length indicate short quality in the form of fighting success
Analysis
1. males with better features are better competitors
  1. females chose the male by the benefits of the offspring
2. ecological factors
  1. mane length
    1. injured males are less able for fighting
      1. manes length, little relation to dominance
  2. mane darkness
    1. higher levels of testosterone, more aggressive
      1. provide information for other lions.
        male dominance, female race
        less likely to be wounded, protection
3. why don't all males have dark mane?
  1. Temperature
    1. lions with dark mane would be affected by heatstress
      1. Global warming

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	Criado por jclavijo13 mais de 8 anos atrás