The aposematic hypothesis
The aposematic hypothesis suggests that the stripes serve as warning colouration as they are recognisable up close. Biologist L. H. Matthews
proposed in 1971 that the stripes on the side of the mouth signal to the animal’s bite. As with known aposematic mammals, zebras have high p
redation pressures and make no attempt to hide.[61] However they are frequently preyed on by lions, suggesting that stripes do not deter them but may work on smaller predators. In addition, zebras are not slow and sluggish like known aposematic mammals.[62]
The social function hypoth
esis states that stripes serve a role in intraspecific or individual recognition, social bonding, mutual grooming facilitation, or a signal of fitness. Darwin wrote in 1871 that “a female zebra would not admit the addresses of a ma
le ass until he was painted so as to resemble a zebra” while Wallace stated in 1871 that: “The stripes therefore may be of use by enabling stragglers to distinguish their fellows at a distance”.[63] Regarding species and individual identification,
zebras have limited range overlap with each other and horses can recognise each other using visual cues.[64] In addition, no correlation has been found between striping and social behaviour among equines.[56] There is also no link found between fitness and striping.[64]
