8. Spotted hyena communication

Question 1

What are some important traits of spotted hyenas?

Answer 1

Smart - high brain to body mass ratio (problem solvers)
Social - Stable clans, multiple matrilines
Cooperative - Hunting and protection
Vocal - Highly acoustic, extensive repertoire
Live hunters - 72% of prey captured live

Question 2

What social structure do spottes hyenas live in?

Answer 2

Clans - big closed societies
- fission-fusion structure
- <90 members
- 29 members in average
- subgroups of 3 on average

Question 3

What does the hierarchy look like?

Answer 3

Strict matrilineal dominance
Rank determines access to resources (downward flow of coalitionary aggression)
Makes always lowest rank
Average relatedness low

Question 4

Why is cooperation within clans important?

Answer 4

Competition against other large carnivores (lions, leopards, cheetahs)
Competition against other hyenas
Cooperative foraging

Question 5

What is the fission-fusion dilemma?

Answer 5

Social pressure: within-group competition => hunt alone
Ecological pressure: extra-clan competition => defend resources together

Solution: Distributed fission-fusion society with collective behaviors when needed

Question 6

How do spotted hyenas coordinate movement and rapid collective action when far apart?

Answer 6

Vocal “whoops” (long range calls)

Question 7

How did Frants study whoops?

Answer 7

Field studies in Kenya
Tag-a-clan experiment
Sound, movement and position logging collars
Whoop detection and identification

Question 8

How do you define and extract recruitment events?

Answer 8

1. Recruitment events are sequences of whoop bouts connected if gaps<20 min
2. Spatiotemporal features of events (epicenter, initial whoop, away whoops)
3. Receiver reactions (recruitment, time of recruitment decision)

Question 9

Define epicenter

Answer 9

Epicenter - the location of maximum hyena density during event (must include a whooper)

Question 10

Define time of recruitment decision

Answer 10

The time when a recruited individual begins movement bout ending at epicenter

Question 11

What factors influence effective recruitment and responses?

Answer 11

Distance to current whooper
Distance to nearest whoop
Number of whoop bouts
Number of whoopers

Reply whoops increases both whoop and reply probability, also range

Question 12

What distance do whoops recruit over?

Answer 12

~ 3 km on average