COMMENT:

One is tall with spots, the other stocky with wrinkles – elephants and giraffes couldn't look more different from one another.

New research has been released that explores how and why these remarkable animals' different skin types develop. In time, these findings could change how we treat challenging human skin conditions.

The giraffe - Giraffa Camelopardalis - was originally named by the Greeks, who thought they looked like a camel with a leopard's spots.

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But how do the giraffe's distinctive spots form? Scientists have previously suggested that the patterns on the skins of giraffes, tigers and zebras form randomly or are shaped by environmental factors.

It seems, however, that these suggestions have come about largely because it is hard for us to assess complex patterns using the human eye – practicality meant that the studies were small, and looked at zoo-based populations of animals (they stood still long enough to be assessed).

To increase the data available, researchers photographed giraffes in the wild - 31 mothers and 258 calves - in Tanzania over a four-year period.

Using modern pattern recognition software to identify and measure each of the coat patterns, they assessed 11 different spot traits including roundness, colour, size and number of spots.

Publishing in the journal PeerJ, the team found that the "circularity", ie how close to a perfect circle the spot is, and the "solidity" - how smooth the spot edges are - seemed to be traits inherited from the mother.

This inheritance seems important, as those calves with fewer but larger, rounder spots had an increased rate of survival.

One of the theories for patterns in animal skins is that they act as camouflage, so it might be that bigger spots help to hide the calves from predators. The reason for increased survival is still not conclusive, however - these spot shapes and sizes could also help to influence temperature regulation or guard against parasites.

The elephant's skin is equally fascinating. African elephants don't have spots like the giraffe - they do, however, appear to have distinctive wrinkles. These wrinkles are only a few microns wide, but help trap 10 times more moisture than smooth skin, and help keep mud stuck to the skin which helps to regulate body temperature, and protects the skin from parasites and sunlight.

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Baby elephants don't have wrinkles. Research, published in the journal Nature Communications, modelled how elephant skin grew and thickened over time.

Previous research found that crocodile scales were made up from skin that had folded over and healed, and the team expected to see a similar process with elephants.

They ran computer simulations on microscopic images of different elephants' skin at various ages, and in fact found that, rather than stretching and cracking as the skin started to grow, elephant skin's inability to shed causes the skin to bend on itself.

Eventually, this bending creates enough stress that the skin collapsed under its own weight, resulting in a crack in the skin rather than a wrinkle or fold. What we see as wrinkles then are in fact tiny cracks.

This unique morphology of the elephant's skin shows a strong similarity to the skin in humans with a reasonably common genetic disorder - ichthyosis vulgaris - that affects 1 in 250 people.

The dry, scaly skin caused by this disorder could be linked to the cracks found in elephants. If a link is found it could help scientists to understand the biomechanics behind the condition in humans, and offer alternatives to help treat the condition.

Nature has so much to teach us, and modern analysis technology is helping researchers to unlock findings that the human eye alone could not.