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Differential foraging strategies: connecting the dots between motivation, perception and implementation in urban free-ranging dogs

MS dissertation research project
by

Madhur Mangalam

on 3 March 2017

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Transcript of Differential foraging strategies: connecting the dots between motivation, perception and implementation in urban free-ranging dogs

217 individual stray dogs,
10:00 PM to 02:00 AM; April, 2011 to March, 2012
Several locations in Pune, India
(cc) photo by medhead on Flickr
Spark
Tip
Reality
This is a huge mountain
Different
perspectives
Differential foraging strategies: connecting the dots between motivation, perception and implementation
Madhur Mangalam
Variability in expected returns
Assured future availability
Enhanced energy balance
Threat
due to predation
Risks
Returns
Food extraction
strategies
Spark
Experiment 1
51 males + 54 non-pregnant/non-lactating
105 dogs
Experiment 1
Observations from experiment 1
Pregnant/lactating (PL)
females
Experiment 2
Experiment 3
20 males + 24 NPNL females
+ 20 PL females
64 dogs
cognitive
High risk
foraging strategies
ecological
evolutionary
Direct selection acting on
fitness consequences of
foraging in resource scarcity
Selection for cognitive mechanisms that underlie a broader repertoire of behaviour
Food distribution is patchy
Foraging time is constrained
(cc) photo by medhead on Flickr
(cc) photo by medhead on Flickr
Nutritional requirements
Returns
Conservative (low risk)
foraging strategies
(cc) photo by medhead on Flickr
Nutritional
intake
No long term advantage
High risk foraging strategies
Canis familiaris
?
Foragers tradeoff the enhanced risks and returns
Foraging
situations
Cost/
benefit
Life-history
Physical condition
Sex,
age
Alternative
strategies
Intra-specific differences
Foraging performance
Fisk evasion
Ecological
Cognitive
Foraging
Information
from the
environment
Behavioral adjustments to
optimize the returns under
manipulated risk conditions
?
Studies on risky foraging strategies
Motivational
states
of animals
Expected
availability
Corrugated
paper board
Corrugated
plastic board
Gestation
Lactation
Higher nutritional requirements
PL females are therefore
expected to perform differently
from NPNL females
Observations from
experiments 1 & 2
20 males + 24 NPNL females
44 dogs
Technique
of food
extraction
Latency in
obtaining food
Q
ualitatively
uantitatively
Residual packets
Rip opening
threat
subject
food packets
trial 2
trial 1
High threat
Safer
Risky
Low threat
Potential losses outweigh the returns
Upon exposure to threat, animals are expected to switch their foraging strategies
Gap wideners had a smaller flight initiation distance than rip openers/failures
Within gap wideners, pre-threat latency in food extraction was positively correlated with flight initiation distance
Within gap wideners, latency in food extraction increased post-threat
Within gap wideners, post-threat increase in latency was negatively correlated with pre-threat latency in food extraction
Foraging
performance
Cognitive
mechanisms
Increased energetic requirements + Hormonal influences
Reduction in
anxiety & fear
If gap widening
involves higher risks
reduces vigilance
Males and non-pregnant/non-lactating (NPNL) females behaved differently
Males performed better than NPNL females in terms of
sophistication of the technique
latency in food extraction
Experiment 1
Relatively
larger body size
in males
Higher
nutritional
requirements
Technique
vs
Sex
During pregnancy/lactation, females behaved similar to the males
Gap widening proved to be faster than
rip opening technique
Experiment 2
Relatively inefficient food extraction in NPNL females
Gap widening
Rip opening
Exposure to threat resulted in lower foraging performance wherein males behaved similar to NPNL females
Gap widening was associated with reduced risk aversion
Experiment 3
Sex-specific differences in the usage of alternative foraging strategies
Experiment 2
Influence of motivational states on foraging performance
Experiment 3
Relationship between foraging performance and the direction of risk evasion in general
Post-threat, the proportion of gap wideners decreased in males
Males had a smaller flight initiation distance than NPNL females
Spark!
Big and....
... small
NPNL females extracted food using the gap widening technique faster that the rip opening technique
Males and PL females used the gap widening technique more often than NPNL females that frequently failed in food extraction
Males and PL females, extracted food faster than NPNL females
Typically, males used the gap widening technique, whereas NPNL females, the rip opening technique
Males extracted food faster than NPNL females
NPNL females guarded food more often than males
Higher performance was associated with higher sensitivity to perceived threats
Use of a strategy associated with reduced risk aversion (possibly due to greater nutritional requirements) resulted in higher foraging performance in males
During pregnancy/lactation, females behaved similar to the males
Foraging performance was positively correlated with both sensitivity and fearlessness to perceived threats
If gap widening is associated with a reduced degree of risk aversion, gap wideners are expected to be less fearful compared to rip openers
Rip opening was always accompanied with food guarding
Rip opening was accompanied with active food guarding
Latency
References
Gap widening
NPNL females guarded food more often than males and PL females
Post-threat, the proportion of individuals that guarded food increased
Foraging task: food extraction from crafted paperboard packets
(NPNL)
females
first attempt to
extract food
food being
ingested
Technique of food extraction
Risk evasion
foraging processes...
Experimental setup
Brihaspati Gaurav
Ritesh Raghavan
Shraddha Karve
Sutirth Dey
...
Acknowledgements
Thanks...
Force NPNL females to use
the gap widening technique
Full transcript