Lion Predation

[Sully]

Exploring the connections between giraffe skin disease and lion predation

Abstract
Rates at which predators encounter, hunt and kill prey are infuenced by, among
other things, the intrinsic condition of prey. Diseases can considerably compromise
body condition, potentially weakening ability of afflicted prey to avoid predation.
Understanding predator–prey dynamics is particularly important when both species
are threatened, as is the case with lions (Panthera leo) and giraffes (Giraffa came-
lopardalis). Importantly, an emergent disease called giraffe skin disease (GSD) may
affect predatory interactions of lions and giraffes. Hypotheses suggest that GSD
may negatively affect the likelihood of giraffes surviving lion attacks. We evaluated
giraffe–lion interactions in Ruaha National Park, Tanzania, where 85% of the gir-
affe population has GSD. We monitored lion hunting behaviour and estimated pro-
portion of the giraffe population with GSD and evidence of ‘lion marks’ from
assumed previous lion predation attempts (i.e. claw marks, bite marks and missing
tails). Although we recorded lions hunting and feeding on 16 different prey spe-
cies, giraffes represented the largest prey category (27%; n = 171 of 641). For age
and sex cohorts combined, 26% (n = 140 of 548) of encountered giraffes displayed
evidence of previous lion predation attempts. Occurrence of lion marks was higher
for adults and males in the giraffe population, suggesting that these individuals
were more likely to survive lion attacks. We also found marginal evidence of a
positive relationship between giraffes with severe GSD and occurrence of lion
marks. Our results identify giraffes as important prey species for lions in Ruaha
National Park and suggest that GSD severity plays a minor role in likelihood of
surviving a lion attack. This is the first study to explore connections between lion
predation and GSD. We explore the ecological implications of disease ecology on
predator–prey interactions and consider opportunities for future research on causal
links between GSD and giraffe vulnerability to lion predation. Reply