Zebra Habitat and the Mystery of Stripes
Given zebra habitat, which is mainly tan colored grasslands, it may not be clear how their stripes might help as an evolutionary trait. If you look out over your typical grassland, you can spot zebras easily and from very far away. The black and white stripes stand out against the tan background.
So how to explain zebra stripes from an evolutionary standpoint? Are stripes just a left over from some previous time when stripes helped zebras to avoid predators in a zebra habitat that has long since changed? Are the stripes a mutation that serves no purpose, just an accident of evolution? Or did stripes happen to come along with some other sort of evolutionary benefit, piggybacking on a useful trait? Are the stripes some sort of signal to mates about the health of an individual zebra, the way bright feathering works in some kinds of birds?
Several theories seek to explain the evolutionary benefits of stripes.
Zebra Habitat
First, we should note that zebras are far more wide spread than you might at first guess. Although grasslands are their primary habitat, zebras also occupy forests and hilly coastal country. In these cooler, tree-lined environments, it is easier to understand how the zebra’s stripes may help to camouflage it against predators.
Zebra Predator Number One: The King of the Jungle
On the other hand, to understand how stripes might help a zebra to survive in the primary zebra habitat, the plains, and grasslands of Africa, you have to understand something about the zebra’s number one enemy, the lion. Zebra’s are not as fast as gazelles or horses. They tend to have shorter legs. The zebra would seem to be no match for the King of the Jungle. However, zebra’s have survived for millennia. How have they escaped this fierce predator?
To understand how stripes help against lions you have to understand that lion’s are colorblind. This makes all the difference, because the reason why we can spot zebras so easily in their natural environment is because we can see the contrast of the black and white stripes in contrast to the tan grasses on which they forage. The lion however, cannot. To the lion, the stripes of the zebra are difficult to distinguish blades of high grass that make up the plains.
The Striped Shield
Other animals, like hyenas, also may have difficulty preying on the zebra because of manner in which zebras defend themselves when attacked by smaller predators like hyenas. Typically when threatened by hyenas and smaller animals the zebras will circle around the calves in the harem (the name for a group of zebras). The hyenas will then try to penetrate this inner circle by luring the zebras out so they can swipe one of the young.
When faced with one coordinated heard however, hyenas might have difficulty distinguishing individual members from the wall of stripes. Some may even see the harem as a large moving striped creature.
Do These Stripes make me Look Hot?
Yet another theory is the stripes help zebras both identify each other and in the mating process. Because each zebra’s stripes are as unique as fingerprints in human beings, zebras may be able to identify each other by these means. Adding to this theory is the fact that zebra eyesight is, unlike the lion’s, very well developed. On the other hand, the stripes also may hide wounds that might exclude a zebra as a potential mate.
Do These Stripes make me Cool?
Yet another set of theories suggest that stripes may help these plains animals to regulate their body temperatures in the hot zebra habitat that is the plains of Africa. Another theory suggests that the stripes may also somehow explain the zebra’s resistance the tsetse fly, one of the great pests of Africa.
The Eternal Question Finally Answered
Like the question of the chicken and the egg, the question of which came first, the black or white stripes has finally been answered by the zebra’s DNA. A study has shown that zebra’s were actually black animals that acquired their stripes later on rather than the other way around.