One such wonder, the thorny devil (Molochhorridus), is an endemic creature that presents itself as a source of contemplation. It is a lizard between 10 and 15 cm long, with a broad body that is completely covered with cone-shaped sharp spikes, and has a rather big head and small eyes. Its appearance is made even more frightening with the two spikes on the sides of its head, which look like horns and are stronger than the others. On the back of the lizard’s head is a separate bump that resembles a second head on which there is another big spike. These unusual physical features have earned it the name the thorny devil. The lizard’s golden and brown patchy skin provides camouflage in the desert environment. Having a lifespan of between 12 and 20 years, this work of art is equipped with unique features that inspire greater awe as they are studied.

Deterrent tactics

Living in the harsh conditions of the desert, the thorny devil is equipped with tactics, each more interesting and unusual than the rest, to keep enemies at bay and stay clear of danger. First and foremost, the thorny devil’s color gets dull when it is frightened or cold, which adds to its melding with the environment. It also breathes in and holds the breath to enlarge its body and thus makes its already frightening appearance even more so. If the tactic does not work to deter the enemy, another strategy is put in place. The creature lowers its head until the lump with the thorn protrudes further. By producing its biggest weapon against the enemy, it seems to say “Don’t you dare come closer” and fends it off.

Skin and feet like a sponge

The most hidden secret of the thorny devil lies in its ability to absorb water through its skin and even feet. The thorny devil is geared up with a special skin make-up that can collect and transport water to the mouth as required by the environment. This structure is a mechanism that involves micro capillary tubes and a network of channels that connects them. The architecture of the network allows for capillary movement, that is, water can resist gravity and move upwards. This is how the lizard is enabled to drink water from sources like ponds, wet sand and droplets condensing on the skin. For example, this little desert creature can absorb water through its feet simply by standing on a little pond, without having to lower its mouth. Drinking water directly from water sources is already difficult, because the tongue and jaw structure of thorny devil is specially created to hunt its prey.

To unravel the intricacies of this mechanism, studies were conducted in the labs of the University of Western Australia on specimens of the Molochhorridus from the Gibson Desert. The studies focused on five water sources that could feed the creature: the rainfall, puddles, moist soil, water droplets from dew, and thermally-induced condensation. The aim was to uncover the effectiveness and efficiency of these sources in the thorny devil’s moisture-harvesting.

In the most striking of these experiments, which looked into collecting water from puddles, the lizards were placed in a puddle of 3 mm deep and the changes in their weight were measured. The thorny devils were divided into two groups as those that drank water and those that did not and were then observed for 60 minutes. It was found that there was a weight increase of 3.66 percent in the lizards with no jaw movement (i.e. non-drinking lizards). On the other hand, the increase in weight was found to be significantly higher at 6.84 percent for the lizards which had rhythmical jaw movements (i.e. drinking lizards). An examination of the jaw movements showed that every jaw movement accounted for the absorption of 0.7 milliliters of water.
To measure the lizards’ absorption of water from “moist sand” they were placed on soil containing different levels of water, varying between 3 to 22 percent. The amount of water absorbed through feet and skin was measured through differences in weight. It was found that water absorption increased proportionately as water content increased. A weight increase of 0.20 percent was found even in soil that contained 2 percent water; in soil with water content of 22 percent, the creature’s water collection amount averaged 1.84 percent. Although little, the increase was concluded to be significant.

Moreover, experiments with “pre-heating with moist sand” showed that pre-heating had a significant impact on the ability of the skin to draw water. It was also found that water collection through “water condensation supported by difference in heat and moisture” caused a weight gain increase of 0.215 percent. These studies show how fantastic a capillary system the thorny devil is equipped with to collect water from different sources, and thereby quench its thirst.
When we lend an ear to this little but amazing creature, we can almost hear it say that every living thing in the nature is being duly taken care of.

Surely God it is He Who is the All-Providing, Lord of all might, and the All-Forceful.
(Qur’an 51:58)

If a gecko’s feet used a secretion to stick to surfaces, they wouldn’t be able to move. And geckos can stick to surfaces, even if there is no air, meaning they don’t use sucking discs. Some scientists suggested an electrostatic charge might help geckos resist gravity, but they’re too heavy for such a charge. Research has shown that  geckos can still cling to surfaces, even if the air is charged with electron ions. If geckos were resisting gravity thanks to electrostatic charges, then the air filled with ions would prevent such resistance.

It turns out geckos are able to adhere to surfaces thanks to the numerous microscopic hairs, or setae, on the bottoms of their feet – as many as 2 million hairs on just one foot. Each of these 2 million hairs further branches out to 1000 more miniscule hairs, totaling 2 billion hairs per foot. The thickness of each hair is one five thousandth of a millimeter. To make a comparison, there are around one hundred thousand strands of hair on a human head. If we had the same number of hairs found on the foot of a gecko, then our hair would cover a surface as large as a football field.

The hair on a gecko’s feet are directed towards its heels. As a gecko steps forward, it presses on the ground and pulls back a little, enabling a maximum level of contact and generating a weak attractive force at the molecular level, called van der Waal’s force, which connects the foot and the ground.

Van der Waal’s force is the bonds between molecules that arise from the forces between positively and negatively charged sectors. An atom has a positively charged nucleus surrounded by a cloud of negatively charged electrons. If the positive charge of the nucleus is equal to the negative charge of electrons, the atom does not carry a charge. Electrons move randomly around the nucleus, sometimes swarming on one side of the atom for a short period of time. When this happens, one side of the atom will have a negative charge, while the other side is positive. Such polarized atoms will momentarily enter into electrostatic interactions with other atoms. This results in an attractive force, which usually lasts for a short period of time. Even though this interaction comes into existence momentarily and then disappears, it is sufficient to hold atoms together in an environment where there are many atoms.

Van der Waal forces do not only appear inside matter and among atoms; they exist even between larger objects, like our hand and the wall it touches. Yet these forces are very weak. At the atomic level, our hand looks like a range of mountains, and only the atoms on top of the summits are in contact with the wall. What makes the gecko unique is that contact occurs between the wall and each one of the millions of hairs on the gecko’s feet. When the gecko lifts its foot, the attractive force is broken. It’s that simple – no suction cups necessary!