Unusual Stripes and Spots Could Spell Trouble for Zebras, Study Claims

Although minor inconsistencies in the appearance of wild animals are normal, nature sometimes causes unique and sometimes rare deviations from the norm. In 2020, two dwarf giraffes were identified from a geographically isolated location, and several melancholic seals have recently been spotted in a seal colony in England in the wake of a winter baby. 

Plain zebras are famous for their ribbons (we even have their naming crossings in England), but they also sometimes practice some artistic licensing, phenotypically speaking.

The study, published in the journal Molecular Ecology, discusses the significance of this alternative coat combination and what it means for species health. Zebras have historically enjoyed a relatively stable population, but the global population is still thought to have shrunk by about a quarter since 2002. Study author Brenda Larison and colleagues fear that abnormally spotted or blonde zebras may be indicators of a decline in genetic health in animals.

Genetic diversity is essential in most species and the catastrophic health effects of reducing gene pool through breeding or selective breeding have been proven in both captive tigers and hereditary health problems. In wild areas, a healthy environment will allow genes to flow freely through the population, ensuring the health of the offspring and the survival of the species.

The flow of these genes can be disrupted by anthropogenic (human) interventions, such as destroying agricultural habitats and establishing cities and towns. To evaluate the gene flow of plain zebras, Larison and his team sequenced the genes of 14 animals that were distributed in nine locations. Seven of those included in the study had abnormal stripe types and the rest isolated normal black-and-white striped coats.

The analyzes proved that the genetic structure did not match the coat type between specific subspecies, but it did identify whether gene flow was restricted as a result of habitat division. The animals of this population are presented with evidence of reproduction. Moreover, those animals that had abnormal coats among the animals tested had an increased propensity to reproduce compared to zebra-striped animals prevalent in their respective populations. “Our results indicate a genetic cause of stripe pattern abnormalities and dramatic evidence of the consequences of habitat division,” the study authors concluded.

Although the variety of coat types may not have a direct negative impact on the health of these animals, standing away from the crowd can be a problem in preventing wild animals from being selected as their mates. Sexual selection favors animals with “healthy” coats, and changes in the zebra blueprint can be interpreted as a sign of the Dodge gene.

Moreover, animal patterns are often adapted to their specific environment, sometimes as a means of breaking up their silhouette so that they are no less visible to predators or a clever way to make it difficult for parasites to land on the skin. Animals that please from the norm can therefore be something of a square shell of a round hole if their new appearance is not suitable for their environment.