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5 Fun Facts About Crabs

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: 

  1. 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 crabs on 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. 
  2. 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.  
  3. 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. 
  4. 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. 
  5. 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. 

 

 

Bonus

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: 

 

 

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. 

 

 

Crab 1
A Lybia with anemone in its pincers (image source)

 

 

 

 

-NISHA PRAKASH 

P.S: Featured image – The Sally Lightfoot crab from the Galapagos Islands. Sacculina – Mental Floss & Wikipedia.

 

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I’m Celebrating My First Anniversary At WordPress & Stories So Wild!

Hey everyone! It gives me great pleasure to announce that today – October 9th 2018 – is My 1 Year Anniversary at WordPress.

It was a year ago that I decided to pick up my laptop and start blogging about a topic that I was most passionate about – wildlife. I thought I’d take this time (and use this post) to talk about my experience so far and the amazing journey I’ve been on during this eventful year. 

I have always loved wildlife. As long as I can remember, I’ve picked up books that dealt with animals, plants, rocks, water bodies…the list is endless. Be it stories by Enid Blyton or memoirs by Jane Goodall, each book held my fascination and still do so today. Although I don’t have an academic background in wildlife and I don’t have much field experience, apart from the ocassional safaris and treks through protected parks, I have always felt the only prerequisite needed to write about wildlife is – passion. And that’s something I have in excess of. 

My journey this year has been amazing and I’ve gone through such a growth curve. I’ve learnt what kind of material ticks in the blogging world, what type of writing format I’m good at, what type of work my readers love to read and most importantly, what type of content gets the word out about the wonderful plants, animals & arthropods that occupy our world. I hope I’ve been able to (and hope to continue to) do my bit to help reduce ignorance and increase empathy towards the wild. 

I have been inspired by so many writers, painters, bloggers, photographers – both on WordPress and those outside it – the list of people whose creative work has inspired my creative juices to flow, is endless. I have gained immense knowledge about the different kinds of science writing in the literary world and I’m now more aware about my responsibilities as a science writer. I am discovering new ways to discharge these responsibilities with care and finesse. 

I have experimented with multiple blog formats over the course of this year and I am now beginning to understand where my future lies in the world of wildlife blogging. For this, I have my readers to thank. Your feedback has helped me find my voice – a voice that works for both you and me – a voice that hopefully works in favour of the wild we are working together to protect, preserve and promote. 

I’d also like to thank my family – my parents & sister – for their constant encouragement, without which I would never have had the courage to channel my passion into words. This blog is a source of comfort and joy to me today. Your critique and directions have helped me hone my writing and they challenge me to take on more challenging topics of discussion each day. 

Finally, I’d like to end by thanking everyone of my readers & followers for being with me on this exciting journey. I hope we can walk arm-in-arm for years to come, learning about the wild we all love so much. 

Have a great evening!

Lots of love, 

Nisha Prakash