Animals have evolved to have many remarkable adaptations to help them survive in the wild. Adaptations are any physical or behavioural characteristics of an animal that aid their survival in its natural habitat. The adaptations could be body parts, body coverings (i.e. markings) or behaviours. Predators have adaptations to make them successful hunters, whereas prey have adaptations to help them escape or hide from predators. Together predator and prey have evolved to out compete each other in what is known as, the evolutionary arms race.
Many African wildlife are famously known for their incredible markings on their fur but what is the reason for these colour, spots, and stripes? How do they hold any evolutionary advantage to their survival?
Let’s start by looking at the elusive leopard…
These large, powerful predators are identified by their beautiful spotted coat. There are nine subspecies of leopard and they are distinguished by their unique characteristics of their coats. These can range from tawny or light yellow in warm, dry habitats to reddish-orange in dense forests. East African leopards are covered in dark, circular spots called rosettes; however, the rosettes of the Southern African leopards are square. The variation in characteristics of a leopard’s coat comes down to their adaptations to their environment.
Researchers at the University of Bristol found that big cats living in dense habitats, in the trees and active at low light levels, are the most likely to have irregular and complex patterns on their coat. Suggesting that the detailed aspects of a leopard’s markings evolved for camouflage. The markings break up their outline and making them hard to distinguish and enabling them to ambush their prey. Predators that hunt in open spaces, like lions do not have any patterns on their coat. Lion cubs have spots on their coat to help them to hide away from other predators during this vulnerable life stage.
Other predators that have evolved spots…
Cheetah are covered in true dark spots on their bodies, this helps to provide camouflage just like the leopard, to help them to remain hidden in their environment whilst stalking their prey. Another species is the serval who rely on their coat for camouflage as they stalk their prey and to avoid predators. The serval has a combination of spots and what appears to be stripes, but are large spots merged together. This makes it difficult to spot a serval in high grass when they are standing still. They have a variation in their spot size on their coats’ dependent on their habitat, they have smaller and lots more spots when living near woodland compared to serval spending more time on the savanna.
Now let’s move onto Zebra with their stripes…
We can all agree that zebra do not win the best prize for camouflage. Their stripes stand out like a sore thumb within their habitat. So, what is the evolutionary advantage of their stripes?
Zebra have the ability to hide in plain sight. Scientists believe that the stripes on the zebra help a zebra from being targeted or an individual being distinguished by a predator when the herd is together. The zebra’s stripes cause, what is known, as the ‘confusion effect’. Dazzling the predators and making it difficult for them to single out a zebra.
Another theory for zebra stripes is for thermoregulation. It has been suggested by scientist that the dark stripes absorb heat in the morning and warm up the zebras, whereas the white stripes reflect light more. Thus, helping to cool the zebra whilst grazing in the blazing African sun.
A more recent theory is the stripes help to act as a natural fly repellent. Scientist have been conducting studies on flies landing on zebra and horses. Horses that where zebra striped fly rugs appeared to have less flies land on them then when they did not wear one. It is suggested that flies would try to land on the stripes, but then fail to decelerate as they normally would approaching a non-striped surface and bounce off.
There are many theories and all sound plausible, all we know is there are complex reasoning behind the evolution of zebra stripes. It is also great to think there are domestic horses in their fields wearing zebra striped rugs!
The final animal I would like to discuss is the Giraffe…
It is fair to say giraffe are very conspicuous in their habitat being the tallest land mammal, however their spots do hold a purpose providing camouflage.
Under each spot (or patches) lies a very complex and sophisticated system of blood vessels. Around each patch are large blood vessels that branch off into smaller vessels under each patch. The giraffe can send blood through these small branches of blood vessels into the middle of the patch to release heat. Each patch helps the release body heat and aids thermoregulation.
Animal adaptations are fascinating!
Come back next Friday for more interesting facts, #factfriday !