The Planet Earth is full of mysteries for the scientists of all specializations. The mysteries of nature seem to be never ending. One of those that has been giving researchers a check for more than six decades is the “Sailing Stones of Death Valley”.  It is a stunning geographical phenomenon where Stones weighing hundreds of pounds move in long tracks along a plain smooth valley without any human or animal intervention. This is observed around the dried lake Playa in Death Valley and also known a Racetrack.  These valleys are filled with dry cracking muddy ground during summer and ice during winter.

Sailing Tones in Racetrack Playa, Death Valley (Pirate_Scott) @wikipedia

Racetrack stones only move every two or three years and most tracks develop over three or four years. With time tracks of each stone varies from the other. Some stones which start next to each other start out traveling parallel, but one may abruptly change direction to the left, right, or even back the direction it came from. Length also varies because two similarly sized and shaped rocks could travel uniformly, then one could burst ahead or stop dead in its track. Some stones make linear turns others make oval turns while others create a wavy shape on their tracks. No one has ever seen them move and nobody knows the speed they move with.

There are many hypothesis proposed for this Sailing Stone phenomenon.  In 1955 George M. Stanley first proposed the theory that the rocks move with the assistance of ice sheets forming after the Playa surface is flooded. Bob Sharp and Dwight Carey started a Racetrack stone movement monitoring program in May 1972. In 1976, they proposed the ice-sheet theory. They analyzed the tracks and concluded because of track characteristics and the geometries of the tracks relative to each other that ice sheets could not have been involved in forming the tracks and moving the rocks. They stated, “It is concluded that wind moves the stones when conditions are just right, that this normally happens at least every one to three years on Racetrack Playa, and that ice sheets are not necessary.” In 1995, John B. Reid, Jr. and other geologists from Hampshire College disagreed with Sharp and Carey’s conclusion. Using data from seven Death Valley visits in the late 1980s through 1994, they support Stanley’s original ice sheet hypothesis. This is however not entirely true because the stones move during the summer when the temperature is too high and even dries the stones themselves.The mysterious sailing stones of Death Valley not only slide on smooth ground but dig and leave shallow track in their wake.

We hope future advanced technology will shed more light no the mystery of the sailing stones at the Racetrack Playa of Death Valley, however no matter how much is determined about the sailing rocks, their beauty and magic will stand as unique creation of Nature.

Mimicking other people or personality is considered as one of the popular comedy act by us. It may look like an intelligent act for human, but nature has already adopted this intelligence for some other reasons. In this article we are covering the expert mimics in the Reptile world.
Milk snake (Lampropeltis triangulum) found in both Northern and Southern American continents are harmless snake. This snake has similar banded appearance like coral snake. This is a form of mimicry and happens only those regions where milk snake and coral snake are found together. In other regions, milk snake doesn’t look like the coral snake. As coral snake is poisonous, this mimicry is to scare any enemies. There is a difference in the band pattern of the both snakes, so it can be identified by human. There are sayings like this to identify the actual poisonous snake: ” Red next to black, you can pat him on the back; red next to yellow, he can kill a fellow.”

Milk Snake(Left) mimicking Coral Snake(right) - courtesy kingsnake.com

Similar to Milk Snake, Scarlet King Snake also mimics Coral Snake . Scarlet King Snake is also non-poisonous. They are born with white bands. The juveniles develop the yellow, apricot, or tangerine colored banding slowly.

The above two are example of snake mimicry where the harmless snakes mimic like a poisonous snake to keep their enemies away. This characteristic is called Batesian Mimicry. It was discovered by scientist H.W. Bate over a hundred years back and named after him only.

Some blind legless lizards that live under the ground trick their enemies by showing their tails. The under side of the tail is usually red or yellow that looks like an open mouth. The enemy attacks the tail mistaking it for head. The tail can withstand much more injury that the head and so the life of the lizard is saved.

Many Lizards have a tail differently coloured from rest of their body. When the enemy attacks them, they break off their tail. The tail jumps about on the ground that confuses the enemy. The Lizard makes a good escape during this confusion.

Another Lizard(Eremias lugubris) in Souther Africa mimics notorious and noxious ‘oogpister’ beetles when young. The adults are cryptically coloured and blend with the red-tan colours of the Kalahari semi-desert.  However,  the juveniles are jet-black and white and very conspicuous and move with stiff, jerky movements with their backs strongly arched and with the paler-coloured tails pressed to the ground. They actually just mimic the Oogpister beetles found in the region and predators avoid the threat of the pungent, acidic fluid sprayed by these beetles when threatened.

A Lizard(anguid) of northeastern Brazil shows striking similarities in color, pattern, size, behavior to the noxious millipede, Rhinocricus albidolimbatus,  when it is juvenile. This is also believed to be a Batesian Mimicry.

Video on Lizard Mimicing Beetle

http://www.snotr.com/video/4732

The Bohol Province of Phillipines is home a true natural wonder, popularly known as Chocolate Hills. The name may sound delicious, but this name is given due to the unique color and shape of the hills found in the region.

Nature's Wonder - Chocolate Hills of Philippines

Chocolate Hills are groups hills spread across an area of around 50 square kilometer. These are perfectly shaped domes of short height, the highest being around 400 feet and the average is at 160 feet. It is hard to believe that these are natural structures but not man made landscape. The hills are beautifully covered with green grass during the rainy season and during dry season the grass get a brown color. These brown color hills look like cookies of chocolate and hence the name.

There is no unanimous geological explanation on these wonderful hills. The most widely accepted theory explains these conical karst hills as formations created ages ago by the uplift of coral deposits and the action of rain water and erosion. A recent theory explains that an ancient sub-oceanic volcano self-destructed and chunks of it were dispersed over the region.

The vegetation of the Chocolate Hills are is unique, covered with various hard grass species, ferns and compositae. It is also home to the unique primate species Tarsier. Unfortunately the flora and fauna of the Chocolate Hills are recently threatened by local querying.