One is not like the other…
Did you guess which is the odd one out? If you guessed that the image in the middle is different, you are right! Although similar looking, those are not bubble tea pearls, but rather, cuttlefish eggs. Sounds bizarre? Well, they can be found right here on our Singapore shores!
Cuttlefish belong to the class Cephalopoda, which includes the octopus and more similar-looking squid. So first, how do we tell cuttlefish (Sepiidae family) apart from squids (Teuthida family)? Both of these marine mammals are molluscs, and while they do not have the characteristic shells of clams, they have stiff structures within their bodies.
Squids have a squid pen, which feels somewhat like plastic to the touch.
For cuttlefish, they have a porous cuttlebone which is used for buoyancy. It is also used as a calcium supplement for birds, and even acts as casts for metal jewellery as it is easy to carve yet resistant to the high heat of liquid metal.
The streamlined torpedo shape of squids helps them to move quickly in water, while the wider, stout cuttlefish moves more slowly with the rippling long fins along the sides of their bodies. In addition, while squids have round pupils like us humans, cuttlefish pupils are w-shaped.
Now that we know how to better tell apart the cuttlefish from their similar looking squid cousins, what is so special about the cuttlefish?
First, cuttlefish have three hearts which pump greenish-blue blood. This is due to copper-containing proteins which transport blood, as compared to iron-containing haemoglobin proteins in humans. Like other cephalopods, cuttlefish can squirt ink to confuse predators as an escape measure. While cuttlefish are unable to discern colour, they can change their body colours through the use of pigment containing cells called chromatophores. Furthermore, they are able to change their body texture too!
During the mating season, males have to compete to mate with a female, with larger males usually gaining the upper hand and getting to mate. How do smaller males get their shot at reproduction? Some of them make use of their camouflage skills and disguise themselves as females, allowing them to sneak up to females to mate! And that is how these black or white bubble tea, pearl-like eggs are formed 😉 Cuttlefish can be commonly found seasonally on our shores and tend to be found near seagrass meadows. I personally saw a clutch of cuttlefish eggs hatching at the intertidal area of Changi Beach!
While it might seem more accessible to appreciate terrestrial wildlife, it is also possible to get up close with marine or coastal wildlife such as these unique cuttlefish in Singapore! In fact, I managed to see these cuttlefish eggs while on a guided walk through the Changi Intertidal. Some guided nature walk programmes include free walks by NParks, and paid programmes by organizations such as the Lee Kong Chian Musuem and Young Nautilus.
There’s much biodiversity to be found in Singapore, as long as you know where to find them! 😊
Written by: Choo Min
Ebert, Jessica (2005). “Cuttlefish win mates with transvestite antics”. News@nature. doi:10.1038/news050117-9.
Spencer, E. (2018, September 13). How to Tell the Difference Between Squid and Cuttlefish. Retrieved from https://oceanconservancy.org/blog/2017/04/07/how-to-tell-the-difference-between-squid-and-cuttlefish/
Tan, R. (2016, October). Cuttlefishes. Retrieved from http://www.wildsingapore.com/wildfacts/mollusca/cephalopoda/sepiidae.htm
Tan, R. (2016, October). Cephalopods. Retrieved from http://www.wildsingapore.com/wildfacts/mollusca/cephalopoda.htm
Yeo, R. (2012, December 6). Cephalopods (Phyllum Mollusca: Class Cephalopoda) of Singapore. Retrieved from http://tidechaser.blogspot.com/2012/12/cephalopoda-of-singapore.html