All living creatures suffer from ill-health at one point or the other. The small and big fishes of the deep ocean are often affected with parasitic infections. At such times, a tiny fish helps them in keeping these infections in check. This is a type of cleaner fish called Wrasse. Continue reading
These creatures are tiny termites (3 mm. in height) but the nests/mounds they build are tall and tough, which can withstand the rough weather as well as attacks from predators. Because of their characteristic castle-like mounds that they construct, these insects are known as Cathedral termites and are considered as remarkable engineers of the insect world. Continue reading
When we look at some creatures, we get a feeling that the Creator surely was in a playful mood and used all the bright colours and shapes to produce these fascinating toys. Some such creatures are — Nudibranchs. Continue reading
We all admire the bright, colourful and shining eyes of a cat. But apart from the colourful prettiness, it also has some unique features.
Fellow blogger (Mr. Amit Misra, pradyot.net) gave a constructive suggestion that instead of always writing about amazing creatures, sometimes strange facts about our everyday creatures also could be written. In addition, today is 181st birthday of French ophthalmologist Ferdinand Monoyer (who invented the eye testing visual acuity chart). So this post is about the special characteristics of the eyes of our domestic cat.
It is assumed that cats can see in total darkness, but this is not true. However, cats can see clearly in only one sixth amount of light that we humans require to see. All eyes have a lens through which the light passes and the amount of the light passing through the lens is controlled by an aperture or pupil. This light then falls on the retina to form an image. The retina is rich with receptor cells — rods and cones. The rods detect light and the cones detect colour.
In the cats, this rods to cone ratio is higher than that in the humans. So, they can detect much more light and have a better vision in dim light. Higher count of rod cells also allows the cats to detect even slightest movement.
The shape of the cat’s pupil is like a slit or elliptical shaped. The opening and closing movements of such pupil are faster than the round pupil of human eye. This helps the cat to quickly adjust to the changes in the surrounding light. (Therefore the cats do not get blinded by sudden brightness like we do).
When the light is in abundance, the slit-like pupil closes to reduce the amount of light entering the eye and thus protects the sensitive retina.
The cats are considered as colourblind; however, they do see the colours but in much less intense hues. The receptors cone cells which are responsible for colour detection are less in number and these cells are not concentrated. So, for the cats some colours are muted than they are to us. They can differentiate blue-violets better than the red side of the colour spectrum.
The cats have a layer of reflective mirror-like cells at the back of the retina. These cells are called as Tapetum lucidum. These cells collect and reflect all the available light within the eyes and so the cats are able to see even when there is hardly any light. These same reflective cells give a jewel like shine to the cat’s eyes in the darkness of the night.
Most nocturnal carnivores and deep sea animals have this layer of cells. It improves the ability to see in the dark but reduces visual acuity.
It is an extraordinary example of design and construction in nature, but the architect of this creation remains a mystery till date.
Small stone-henge like structures woven out of silk were found in the regions of Amazon. These structures are built very intricately with a stone-henge like fence around it. However, the creature that constructs this delicate silk structure has not been seen till date and remains a mystery.
First such silk structure was found in 2013 in the Tambopata National Reserve in Southeast Peru. It was a small silk ball, surrounding by tiny picket fence posts. The posts, too, were connected with silk and the diameter of the entire structure was 2 cm.
Later, during the same year, fifty more such structures were discovered, but in each case the spider or the arachnid who built it was never seen around it. In some areas even clusters of these were found, and possibly they were built by a same female specimen.
The scientists observed and studied this further and found a translucent, orange spiderling hatching out of the central egg-sac.
The extraordinary video of this hatching and the comments of the scientists can be found: Here
This elaborate structure is built for a single egg. The scientists speculated that the silk fence around the egg sac could be either to protect the egg sac or to lure mites/ants and catch these insects fro the the hatchlings to eat. Such structures were also found in French Guinea and Ecuador.
The translucent, orange hatchling:
Generally the spiders do not lay eggs and abandon them, they always place the silken egg sacs in their webs. This is an only instance of a spider laying only one egg per sac. According to the scientists, the Cribellate spiders are known to build elaborate structures, however, there were also doubts about fungus or caterpillars being the creators of such structures. The scientists also studied the DNA, but it doesn’t match with any in the database. So it is assumed that it is some new, hitherto unknown species.
Pom Pom Crabs
These crabs are also called as the Boxer crabs or the Cheer leaders of the deep sea. The reason behind these names are the sea-anemones that these crabs carry in each of their claws, making them look like the cheer leaders with pom poms in their claws. Continue reading
Human beings, especially those living in rural or tribal areas, are known to use mud or clay to reinforce the walls of their humble homes. But when members of avian group are found building their homes with mud, we are yet again compelled to marvel at the amazing things happening in nature. Continue reading