A new University of Queensland-led study has revealed that the color of spots in male giraffes (Giraffa camelopardalis) more strongly relates to their patterns of social association, rather than their age. The findings are published in the journal Animal Behaviour.
Younger and paler old male giraffes (Giraffa camelopardalis) are gregarious while darker males are more solitary. Image credit: Albert Dezetter.
“Male giraffes tend to increase in darkness as they age, but some males never darken and others even lose pigmentation,” said study lead author Dr. Madelaine Castles, a researcher in the School of Biological Science at the University of Queensland.
“We now know that — rather than simply indicating age — color may display males’ physical condition and be used as a way to signal competitive ability to others.”
“Male giraffes’ color may function in a similar way to the lion’s mane, as lions with dark manes are usually dominant and are preferred by females.”
“We think that darker, more dominant male giraffes use an often-successful but risky mating tactic, roaming between groups of giraffes looking for sexually receptive females.”
“In contrast, the lighter, less dominant males may be making the best of a bad situation so to speak, by remaining with females in the hope of getting lucky when a dominant male is not around.”
Dr. Castles and her colleagues from the University of Queensland, CNRS and Newcastle University analyzed the coat color and sociability of 66 wild male giraffes over 12 years at Etosha National Park in Namibia.
“These findings are just the beginning of understanding giraffe color,” said co-author Dr. Anne Goldizen, also from the School of Biological Science at the University of Queensland.
“The next step is to find out how color could be a signal of a male’s condition.”
“Color could be linked to testosterone, to heat stress, diet, genetics or a combination of multiple factors.”
“The more we learn about giraffes, the more questions we have.”
“And giraffes have recently been moved from ‘of Least Concern’ to ‘Vulnerable’ on the IUCN Red List, so further research on these gentle giants is critical.”
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Madelaine P. Castles et al. 2019. Relationships between male giraffes’ colour, age and sociability. Animal Behaviour 157: 13-25; doi: 10.1016/j.anbehav.2019.08.003
