Crabs are crustaceans, marine animals which have a thick exoskeleton made of a chemical called chitin (which is chemically derived from glucose). Crabs belong to the class Malacostraca, which means “soft shelled animal” and to the order Decapoda, which mostly includes marine crustaceans (like lobster, shrimp and prawn) that scavenge for food, as opposed to hunting them. This makes crabs soft-shelled scavengers.
Here are five fun facts about them:
There are two types of crabs in the world – true crabs and false crabs – classified so because of their differing physiology. True crabs have the traditional body structure of a crab – a short and shallow abdomen curled underneath the shell and 4 pairs of legs excluding the pincers. False crabson the other hand, look a little like crabs, but not completely. They have longer abdomens and less than 4 pairs of legs. True crabs include spider crab, blue crab and ghost crab. False crabs include king crab, hermit crab and porcelain crab. There are a total of 5000 crabs in the world – 4500 true crabs and 500 false crabs.
The largest crab in the world is the Japanese Spider Crab, which measures 13 feet or almost 4 meters from one end of the body to another. In comparison are the Coral Gall crab, Pea crab, Marsh Fiddler crab and Flattop crab – all of which measure in at a teeny-tiny half an inch at adulthood. If you kept 4.5 standard sized mail boxes one-on-top-of-the-other on one side and a small pea on the other side…well, that’s how the size difference would look between these crabs.
A small species of crab called Lybia or boxer crab, carry stinging anemones in their pincers anywhere they go. Why? Lybia are very small in size and they don’t have venom to protect themselves from predators. They use the anemones in a mutually-beneficial partnership where the anemone acts as their defensive, venom-filled gloves. If an animal were to attack the Lybia, the anemone would sting the predator, protecting the crab. In return, the crab takes the anemone to different water bodies, allowing it to feed-off various sources and gaining valuable nutrients not found in its native environment.
If a crab loses its limbs in a fight, it can grow them back in a matter of months. This is a feature that is also found in starfish and lizards.
Crabs walk sideways because their legs are positioned to the sides of their body and their joints bend outwards and sideways. The reason for this type of evolution traces back to the crabs’ feeding behaviour. As sand-digging scavengers, crabs never needed to move forwards or move fast. This meant they didn’t need forward bending legs (which are one of the reasons animals can walk or run fast) and could make-do with sideways legs and sideways walking. However, not all crabs walk sideways. Frog crabs and spider crabs belong to the handful of crab species that walk forwards.
There is a type of parasitic barnacle called the Sacculina, which injects itself into the crab’s body, takes control of the crab’s will and makes it do its bidding. Crabs infected by Sacculina can’t control their own body mechanisms and are forced to become walking, breathing incubators of Sacculina eggs. Read this highly-informative article to learn all about the relationship between the Sacculina and its crab host.
Here’s what a crab infected by Sacculina look like:
Sacculina before it expels its shell
Sacculina after it expels its shell
Video: Coconut tree crabs are the only type of crabs that can climb trees. Watch this monster of a crab climb a tree, bend coke bottle caps and more.
Dung Beetles are members of the order Coleoptera,which include insects that have hardened wing cases and not papery wings like other insects. As members of coleoptera, they belong to the super-order Endopterygota, which constitutes insects whose bodies undergo a drastic transformation from how they are in the larval stage to how they are in the adult stage. Other insects that share their super-order are bees, butterflies, flies and ants.
Here are 5 fun facts about dung beetles:
We all know that dung beetles love to eat poop. But research shows that dung beetles have a blatant preference for herbivore poop, given the high nutritional value it has from the undigested plant matter. Carnivore and omnivore droppings which contain much less nutrition than what beetles require, are only consumed occasionally.
Did you know that dung beetles have been around from the past 30 million years? Fossil records in South America show prehistoric dung balls, similar to the dung balls today’s dung beetles make, around sites where herbivorous dinosaurs were found. Looks like someone was a good samaritan, keeping dino poop off the streets.
Although the quintessential image of a dung beetle is that of a beetle pushing around a ball of poop, most dung beetles actually don’t indulge in this behavior. Many dung beetles either live within piles of animal poop or burrow holes into the ground below the poop, as these help the beetles gain quick access to the poop when they’re hungry. Dung beetles only roll their dung when they need to carry food to their nests, which may be far away from the pile of fresh poop.
One type of dung beetle from Africa, the Scarabaeus satyrus, uses the Milky Way Galaxy to navigate and travel. When this beetle needs to transport its ball of poop, it waits for it to get dark, gets on top of the poop ball, looks towards the sky, finds the milky way and uses the stars to make its way home. If anything blocks their view of the stars (like scientists did when they placed tiny hats on these dung beetles to check their navigation reflexes when blind), these beetles will wander aimlessly like lost puppies. Talk about requiring celestial guidance.
If you thought a tiny hat didn’t complete its trousseau, don’t worry. There’s more to come. To test whether dung beetle poop-ball-rolling efficiency was affected by the heat of the midday sun, scientists put selected dung beetles in tiny silicon booties. They noticed that the beetles wearing the booties took lesser breaks and were faster in their walk & poop-rolling.
With all this talk of poop-rolling, don’t you want to know what weight a dung beetle can pull during each poop-rolling session? A dung beetle can pull as high as 1,141 times its own body weight! That’s the equivalent of a 70 kilograms human being pulling six double decker buses filled with people!
Here is what we do in the name of scientific inquiry:
Sea Sponges are multi-cellular creatures that do not have a brain and organ systems and depend on the constant flow of water through their porous bodies to get the oxygen and food they need to survive. There are over 9000 recorded varieties of sea sponges in the world today and they can be found at various depths right from the seashore to the abyssal zone, which is the deepest part of the ocean.
Here are 5 fun facts about them:
Fossil records of sea sponges indicate that sponges first made an appearance on the Earth 650 million years ago. This makes them one of the earliest life forms on the planet.
There are currently 480,931 marine species known and on record and an estimated 2 million that are as yet unrecorded and unknown (i.e. there is not enough evidence – be it visual proof or physical proof – to classify any unknown animal as a distinct species) in all the lakes, seas and oceans of the world. It’s believed that 75% of the world’s entire marine population (480K + 2 Million) accounts for sponges.
Since they don’t have any age-rings (like in trees), it can be hard to accurately estimate the age of a sea sponge. But analysis of growth rates indicates that some sea sponges grow 0.2 mm (0.000656168 feet) per year. Based on this, sponges as small as 1 meter (3.2 feet) wide may be over 4500 years old!
A sea sponge in the Caribbean – Tectitethya crypta – produces two chemical compounds which can treat certain types of cancer and HIV. The chemicals – spongothymidine and spongouridine – have been used to develop the HIV drug Azidothymidine (AZT) which can be used to prevent mother-to-child and needle-to-skin AIDS/HIV transmission. The same chemicals have also helped create medication for leukemia and herpes.
The biggest debate since the time of Aristotle has been – “Are sea sponges plants or animals?” Although they resemble plants in appearance and remain permanently fixed to the spot they grow on like plants, sea sponges are not plants. Why?
– Sea sponges can’t produce their own food like plants and rely on stray organic matter to float into their pores via the flowing water.
– Sea sponges have an immune system like other animals which reject dissimilar cells if transplanted into them. Scientists need to use immunosuppressants to successfully transplant dissimilar cells into their bodies.
– Finally, some sea sponges produce and release sperm to indulge in sexual reproduction.
These characteristics makes sea sponges inherently animal-like.
Today, you can find a feminine hygiene product called “Menstrual Sponges” on the market. Basically, these are sea sponges that are used as re-usable tampons. In many parts of the world (especially in developed, first-world countries), sea sponges are a favoured alternative to toxic, non-biodegradable and expensive sanitary pads and tampons. Here is a link to theTop 5 most preferred sea sponge tampons.
Centipedes & Millipedes both belong to the group “Myriapoda“, under the phyllum “Arthropoda“, which includes spiders, crustaceans and insects. We know they have a seemingly never-ending number of legs, with one having more legs than the other (20-350 legs in centipedes & 40-750 in millipedes). But is that the only difference between them?
5 differences you didn’t know existed between centipedes & millipedes
Centipedes are flat, while millipedes are cylindrical. Centipedes are yellow-gray in colour, while millipedes are reddish-brown or black in colour.
Centipedes have a single pair of legs in each segment/section of their bodies. Millipedes have two pairs of legs in each segment/section of their bodies. Centipedes’ legs are spread outwards and away from their body, towards their side. Millipedes’ legs are directly under them.
Centipedes are venomous, whereas millipedes are not.
Speaking of venom, centipedes use highly-toxic venom like hydrogen cyanide or hydrochloric acid to injure, immobilise and hunt small prey like insects, worms and in the case of the Venezuelan giant centipede, bats. Millipedes on the other hand, are predominantly vegetarians, dining on decaying leaves and rotten tree bark. They only eat insects if they are easily available and the millipedes don’t need to expend too much energy catching them.
Centipedes die if they don’t find a wet and moist place to live, whereas millipedes are quite versatile and can adapt to any environment – dry or moist. That leggy arthropod that just crawled out of your kitchen sink – that’s a centipede. It’s cousin you see scuttling around inside the storage boxes and wall cracks in the basement – that’s a millipede.
During mating, centipede males leave bundles of sperm next to female centipedes and move away. The females use these bundles only when they find the perfect nest to lay the fertilized eggs (if the timing isn’t right, female centipedes store these sperm bundles for a better day). Millipede males & females on the other hand, engage in sexual intercourse to reproduce. Male millipedes have been observed giving “massages” to females to get them in the mood for sex.
A jellyfish’s body is made of 98% water. They can dehydrate and disappear if they wash up on shore on a very hot & sunny day.
Jellyfish have the ability to clone themselves. If injured or cut in half, a jellyfish will heal itself and then clone itself to create two healthy organisms.
The Turritopsis nutricula jellyfish found in the Mediterranean Sea is capable of reversing its age once it reaches adulthood. How? When the Turritopsis nutricula becomes an adult, it starts changing its fully-grown cells into infant cells, essentially becoming a baby. This way, it remains young always. It is the only recorded animal to be completely and truly immortal.
In early 2000, fishermen in the Gulf of Mexico caught a monster-size jellyfish – almost 70 feet long and with sharp, extremely poisonous tentacles. This jellyfish was pink in colour and had never been sighted before. Scientists dubbed it the “Pink Meanie” and it is now one of the rarest and the second largest species of jellyfish in the world, reaching record lengths of 100 feet. The only jellyfish larger than this is the Lion’s mane jellyfish, which stands at 120 feet (that’s 3.5 times longer than a telephone pole!).
Jellyfish are more than 500 million years old, making them older than dinosaurs. Their ancient legacy can be attributed to their lack of a sophisticated physical body. Jellyfish don’t have any organs and only use their skin and a simple network of nerves to live. These combined make them very less physically demanding, requiring less to survive.
In 1991, NASA sent adult jellyfish into space on board the Columbia space shuttle. The objective was to find out whether space-born babies can survive a life both in space and on the Earth. It turns out that the baby jellyfish born in space developed extreme vertigo when they returned to Earth and most never learned how to swim in Earth-water after their extraterrestrial stint, because their newborn bodies never learnt how to recognise and deal with gravity. Researchers believe human babies too may face similar challenges if they are born in space. This makes relocation to Mars (or any space-bound journey) all the more challenging for humans.
Video: The world’s largest jellyfish has a very small, but very deadly predator – Anemone. Watch as this giant is ripped to shreds by a hundred little arms.
P.S: Featured image: Fried egg jellyfish – they live for only six months, born in the summer and dying in the winter.
Snail eggs are enjoyed as “white caviar” by people around the world. Did you know that a kilogram of snail eggs costs €4,000? These eggs are supposed to taste very earthy & strong.
The Giant African Snail is the largest snail on the planet, measuring 30 cms (almost 1 foot) long! Halfway around the world in China, you’ll find the world’s smallest snail – Angustopila dominikae – which measures only 0.86 cms long.
The digestive juices of snails are a great cure for bronchitis and acidity in humans. In a late 1990s survey researchers discovered that populations that eat snails regularly have a death rate that is 20X lower than populations that don’t.
Most land snails are herbivores and are practically harmless. On the other hand, all aquatic snails are omnivores, often the top of the food chain at the bottom of the ocean. Sea-dwelling snails use sharp harpoons and produce potent sulfuric acid to hunt.
Ever seen the slimy, mucous-like trail left behind by snails? Snails produce this mucous to protect themselves from the hard and dry ground they travel on. They spend 40% of their energy producing this mucous, which can really tire them out. That’s why many snails try to cheat their way out of this by using a slimy trail left behind by another snail.
Did you know snails have a mortal enemy?
Pouring salt on a snail is akin to signing its death warrant. Snail bodies are made mostly of water and other bodily fluids. When you pour salt on snails, the salt absorbs the liquids from the snail’s body through a process called “osmosis”. While a little salt will make the snail dehydrated, a lot of salt can kill it in minutes.
Farmers know this and routinely pour salt at the base of plants to prevent snails from wreaking havoc on them.
Here’s what happens when you pour salt on a snail (viewer discretion is advised)
When a snail starts drying up, its body produces a slimy substance to preserve any moisture that remains. The bubbles you see forming on the snail is the chemical reaction between the slimy mucous and the salt.