Females and Food: Types of relationships

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Females and Food Types of relationships
Types of competition Types of relationships
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Types of competition

• Contest

• Scramble

• When food cannot be monopolized by other
  individuals or defended, first come first serve.

• When food can be monopolized by other
  individuals, often involves direct conflict

(either impossible to defend, or not worth it)
(worth defending, monopolizable)
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Competition levels

• WITH-IN GROUP

• BETWEEN GROUP

• Between members of DIFFERENT groups ( or
  communities)

• Between members of the SAME group (community)

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Three dimensions used to describe primate
relationships

• Despotic versus egalitarian

• Individual versus Nepotistic

• Degree of Tolerance

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Within Group Relationships (1)

• Despotic

• Egalitarian

• Formal dominance relationships, hierarchy,
  usually linear

• Weak relationships, no hierarchy, or friendly
  relaxed relationships

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Dominance definition

• Pecking order

• Hierarchy

• Often Linear

Definition when Animal A consistently elicits
submissive actions from Animal B, and rarely or
if ever directs submission towards B (or other
animals) A is said to be dominant.
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Linear Hierarchy

• A gt Bgt CgtD etc...

Male versus female
Matrilines
Male hierarchies
Age related ranks
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Male versus female
Gorilla

• In many species, males are dominant to females
  (sexual dimorphism).

Rhesus monkey

• In others, females are dominant to males (little
  or no dimorphism).

Pygmy chimp
lemur
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Matrilines
Rhesus monkey

• Clear hierarchy within matrilines (female and her
  offspring, other relatives) and between
  matrilines.

Ring-tailed lemur
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Matriline patterns

• Philopatric- females remain in natal group for
  natural lives

• female bonded- female relationships are most
  important

• nepotisim- who you know and are related too
  matters.

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Rank acquisition

• Among females rarely see turnover in rank.

• Sometimes (rarely) low ranking matriline can
  overthrow a higher ranking one

• Youngest sister ascendancy- younger sisters
  outrank older ones. Why?

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Some other possibilities...

• Sometimes other way round, older sisters outrank
  younger (yellow baboons)

• Daughters over throw moms (ruffed lemurs)

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How does food change things?

• Japanese macaques-

Provisioned populations high density of food,
high density of primates youngest sister
ascendency
Unprovisioned populations low density of food,
low density of primates less emphasis on
hierarchical relationships.
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Advantages of rank?

• First access to food, sleep sites, resources

• Translates into increased Reproductive success
  (fitness)

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Not clear cut though...

• Yellow baboons- dominant females dont have
  higher RS, but start reproductive careers earlier
  (200 days).

• Olive baboons- dominant females have higher RS,
  shorter inter-birth intervals (IBI), dominant
  daughters mature faster, but higher stress and
  miscarriage potential (stress).

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Rank turnover and place in hiearchy?

• Howling monkey

Females rise in rank, Then drop back a notch Why?

• How meaningful is the difference between 15 and
  16 in a group of 30?

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May have something to do with..FOOD!

• Toque macaque monkeys and vervets.
• When food scarce or droughts occur, rank plays a
  more important role in RS.

• In lemurs, it looks like degree of female
  dominance over males depends on food
  availability.

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Individual versus Nepotistic (2)

• Somewhat reflects whether group is dominant or
  egalitarian.

• Nepotism when female relatives assist each other
  (coalitions). rank and degree of assistance are
  intertwined.

• Individual Female rank is independent of
  relationship with others (age), kin relationships
  are less important.

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Examples

• Nepotism- baboons, macaques. Can have nepotistic
  relationships without strong dominance hierarchy
  (patas monkeys, lemurs)

• Individual- can have individual relationships
  with hierarchy (howling) or without (gorillas).
• Female-female harassment

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Degree of tolerance (3)

• Picture it as a continuum.

• As degree of tolerance between individuals
  increases, degree of agonism will decrease.

• Can have highly tolerant animals in a linear
  dominance hiearchy.