According to a new study, published in the journal PeerJ, some features of a giraffe’s spot pattern are passed on from mother to baby.
Newborn giraffes with large and irregularly shaped spots survive better during their first few months of life. Image credit: Derek Lee, Wild Nature Institute / Pennsylvania State University.
“Giraffe spot patterns are complex and can be quite different among individuals, but we don’t really know their purpose in the wild,” said study first author Dr. Derek Lee, a researcher at Pennsylvania State University and Wild Nature Institute.
“Complex markings can help animals evade predators, regulate their temperature, or recognize family or individuals, all of which can affect their ability to survive and reproduce.”
“We analyzed survival records and photos of spots of Masai giraffes (Giraffa camelopardalis tippelskirchii), and show that spot patterns do affect juvenile survival and are heritable — they are passed from mom to baby.”
Giraffe skin color is uniformly dark gray, but their spots are highly variable in color and shape, ranging from nearly round with very smooth edges to elliptical with jagged or lobed edges.
Spot patterns do not change as an animal ages, which allows researchers to identify individuals based on their unique patterns.
Lee et al used modern image software and statistical methods to confirm a 49-year-old hypothesis that giraffes pass on features of their spot patterns to their offspring. Image credit: Pennsylvania State University.
Dr. Lee and colleagues found that newborn giraffes with larger spots and irregularly shaped spots also had increased survival during the first few months of life.
This increased survival could reflect better camouflage of these young giraffes, but it also could be related to other survival-enhancing factors, such as temperature regulation or visual communication.
The scientists also found that two of eleven spot traits measured, circularity (how close the spot is to a perfect circle) and solidity (how smooth and complete the edges are) were significantly similar in mothers and calves. This suggests that these traits are inherited by the calf.
“Dr. Anne Innis Dagg, the first giraffe field researcher in Africa, presented evidence in 1968 that the shape, number, area, and color of spots in giraffe coat patterns may be heritable, but her analysis came from a small zoo population,” said study co-author Monica Bond, a Ph.D. student at the University of Zürich.
“We used wild giraffes and modern imaging and analysis techniques to confirm her conclusions.”
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D.E. Lee et al. 2018. Seeing spots: quantifying mother-offspring similarity and assessing fitness consequences of coat pattern traits in a wild population of giraffes (Giraffa camelopardalis). PeerJ 6: e5690; doi: 10.7717/peerj.5690
