My first blog post on marine life behavior and physiology - The Cuttlefish!
So you think you know all about the cuttlefish? I was researching on the cuttlefish (as opposed to the squid, a common question from divers) and found out these incredible facts!
1. Do you know that....
...the cuttlefish is color blind?? Wow! and yet it can detect its substrate environment and rapidly alter its own skin color, contrast and texture at will to blend in with excellent camouflage skills! It also changes its skin texture as a way to communicate with other cuttlefish.
2. W shaped eyes
If you see carefully, cuttlefish has a smooth W shaped eyes but not the squid. Squid eyes are big and round :)
3. Buoyancy
Don't you sometimes wonder how these beautiful creatures just 'float' gracefully about without seeming to use much effort like us humans? haha...this is why - The cuttlefish controls its buoyancy by CHANGING THE GAS-TO-LIQUID RATIO in its unique and porous internal chambered cuttlebone. This cuttlebone cannot be found in squids, and is a key distinguishing factor between squids and cuttlefish. Such a good balancing act huh?! :)
Don't you sometimes wonder how these beautiful creatures just 'float' gracefully about without seeming to use much effort like us humans? haha...this is why - The cuttlefish controls its buoyancy by CHANGING THE GAS-TO-LIQUID RATIO in its unique and porous internal chambered cuttlebone. This cuttlebone cannot be found in squids, and is a key distinguishing factor between squids and cuttlefish. Such a good balancing act huh?! :)
4. I wanna be alone!
As opposed to the squids which usually form groups and swims in mid-water, the cuttlefish prefers to be alone or with 1 other cuttlefish (usually when mating) and settles on the sea bed hunting for crabs and shrimps. So if you spot it at the bottom, it's probably a cuttlefish :) (though an exception is night time when the squid is attracted to light and may come and accompany you on your dive due to your torch light)
5. Circulatory System
A cuttlefish actually has 3 hearts (!). On top of that, cuttlefish blood is copper-based (as opposed to iron-based), thereby explaining why it is greenish in color instead of red. Because of its tedious circulatory system (since copper based blood cells carry a lot less oxygen than hemoglobin), a cuttlefish eventually dies at about 18 -24months.
6. Brain Size
The cuttlefish is among the most intelligent vertebrates in the ocean...the size of its brain explains why. It has one of the largest brain-to-body ratio among vertebrates! :)
7. One year to spread its seeds, before dying
A cuttlefish starts mating from the age of about 6 months, and since it dies about 18 months, it has only about 1 year to reproduce. During this time, it reproduces about 1,000 eggs! Cuttlefish eggs are singular and hidden deep in corals (except for the flamboyant cuttlefish eggs that are laid on half coconut husks or mushroom corals and then turned upside down), but squid eggs are stringed up like pea pods (5 in a string) and displayed quite openly!
The first picture below is the egg of a cuttlefish hidden among fire corals so that the other predators such as butterfly fishes aren't able to reach them.
The first picture below is the egg of a cuttlefish hidden among fire corals so that the other predators such as butterfly fishes aren't able to reach them.
Now, these below are the eggs of the flamboyant cuttlefish. They were found being laid on a flat mushroom coral and turned upside down to be protected from predators. These are still young babies!
8. Master of Disguise
Some smaller male cuttlefish deploy a very clever strategy to mate with a female (there are sometimes 8-10 males fighting for 1 female!). The male may pretend to be female, by changing its color, hiding two of its arms (males have 4 pairs and females have only 3 pairs), and even pretend to hold an egg sack (haha!). By disguising as a female, it will successfully swim past the dominant males and mate with the female.
9. Too many choices for Sperm selection
To top it off, the female cuttlefish also has a reproduction strategy like the turtle, storing the sperms of different male cuttlefish that it mates with and finally only choosing the sperms of one of them. Guess what they usually choose the sperm of the clever male that disguised as female, probably because genes from the more intelligent males are preferred...part of natural selection of the fittest! :)
Some smaller male cuttlefish deploy a very clever strategy to mate with a female (there are sometimes 8-10 males fighting for 1 female!). The male may pretend to be female, by changing its color, hiding two of its arms (males have 4 pairs and females have only 3 pairs), and even pretend to hold an egg sack (haha!). By disguising as a female, it will successfully swim past the dominant males and mate with the female.
9. Too many choices for Sperm selection
To top it off, the female cuttlefish also has a reproduction strategy like the turtle, storing the sperms of different male cuttlefish that it mates with and finally only choosing the sperms of one of them. Guess what they usually choose the sperm of the clever male that disguised as female, probably because genes from the more intelligent males are preferred...part of natural selection of the fittest! :)
10. Flamboyant cuttlefish
If you think that cuttlefish are pretty harmless, hear this - the flamboyant cuttlefish which is one of the prettiest, easily approachable and most amazing color-changing creature underwater, is actually found to have poison as lethal as the infamous blue-ringed octopus that can kill you in 10 minutes if you get stung.
Researchers are still finding out more about the poison that the flamboyant carries, but the bottom-line is: don't touch any thing underwater!
So there...just some of the amazing facts about the cuttlefish. There are more..such as the cells that enable them to change colors rapidly, and the way it paralyzes preys with poison before feasting, and how the eyes can look forward and back. All in all, the cuttlefish is one amazing creature we all need to learn more about! :D
Genius
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