What on earth is this creature?

We were fortunate to go on two night dives while at Taveuni Island with Susan from ‘Wiz’. On our second night dive, a few nights ago, Susan started madly flashing her torch to get our attention, and there before us was a weird creature about 30 cm long and hovering over the reef. At first, I thought it was an octopus with its legs tucked in but then guessed it was a cuttlefish.

Despite being called a cuttlefish, it is not a fish but rather a type of mollusc known as a cephalopod and closely related to the octopus, squid and nautilus. Like that of an octopus the cuttlefish also has eight arms. The really weird thing we noticed about the cuttlefish is the fin which resembles a short, flouncy skirt that flaps around the body. The fin manoeuvres the cuttlefish forward, backward and even in circles, as you can see in the video below.

Watch the cuttlefish moving through the water.

You can see the fin on the underside of the cuttlefish that glows blue in the photos above that Tristan took.

In photo on the left surrounding the body you may be able to see the very thin fin, it looks slightly blurry as it was flapping while the photo was taken. Photo 2 shows the cuttlefish’s eight arms.

Well you may not have seen one in the sea before, but chances are that if you have ever walked on the beach you may have seen the remains of one washed up on the sand. I can remember seeing them on the beach when I was young and we would take it home and put it in the cage for our cockatoo. The cuttlefish bone is rich in calcium which is why it is often sold in pet stores for birds as a nutritional supplement. In fact the cuttlefish bone controls the animals buoyancy by adding different amounts of liquid or gas into it which allows them to move up or down.

Have you ever seen one like this on the beach?

Both octopus and cuttlefish are masters of disguise. Cuttlefish can change not only their colour and pattern but also the texture of their skin, as their skin possesses up to 200 pigment cells per square millimetre. Also like the octopus and squid the cuttlefish too has an ink sac which it can use to deter predators. No, we did not see the cuttlefish shoot any ink. The purpose behind the colour, pattern and texture change are for the cuttlefish to evade or deter predators or to mimic other species to help them catch their prey or to communicate with other cuttlefish.

Can you see the nodules on the cuttlefishes body that allows it to blend with the coral behind it, pretty cool right?

Look how its changed colour and pattern to blend with it’s surroundings.

In this photo it has changed to red and all of the textured nodules on its skin have disappeared.

Interestingly enough, although the cuttlefish have highly developed eyes with the ability to reshape its eyes, it is in fact colour blind. The cuttlefish’s eyes are not only very large in comparison to its body but the pupils are in a W shape.

Can you see it’s ‘W’ shaped eye? This is one of Tristan’s photos.

We think that this particular cuttlefish belongs to the species known as the broadclub cuttlefish which is found in both the Indian and Western Pacific Ocean. It is the second largest cuttlefish species reaching up to 10 kg.

Some interesting facts about cuttlefish:

  • The female cuttlefish dyes her eggs black using her ink and they resemble a grape. The eggs are sometimes called sea grapes.
  • Like the octopus, cuttlefish have three hearts and blue blood.
  • Cuttlefish have a relatively short life span of only 1 – 2 years.
  • Cuttlefish can use jet propulsion to move quickly by filling their body cavity with water and then squirting it out, which will propel them backwards.
  • The cuttlefishes’ brain to body size ratio is one of the largest of any invertebrate, perhaps even larger than the octopus.

Information on the cuttlefish came from the following sites:

Banded sea Krait

All countries have interesting sea creatures; one which Tristan and I have had on our list to see in Fiji is the banded sea snake otherwise known as the ‘banded sea krait’ or its scientific name, Laticauda colubrina. The banded sea kraits’ name stems from the fact that they have white bodies with black vertical stripes. The female is three times heavier and can reach 128 cm (50 inches), whereas the male grows to only 75 cm (30 inches).

The one was well over a meter long so, it must have been a female!

This snake is highly venomous, 10 times greater than that of a rattlesnake. The yachty rumour is that they can’t bite you because they have a small mouth and the only place possible would be between your thumb and finger, this is however an old wives’ tale. They tend not to bite because they are not particularly aggressive, but there have been cases where fishermen have been bitten while bringing in their nets.

The clip is from a dive on Paradise Resort’s house reef in Fiji.

What is special about this snake compared to other sea snakes is that it doesn’t spend all of its time in the water. The snake comes ashore to nest, find fresh drinking water, to rest and digest their food and use rocks onshore to help shed their skin. In fact after diving with three banded sea snakes we went to the dinghy dock at Paradise Resort in Taveuni and there was a small one sunning itself on the rocks! Unfortunately no one had a camera to photograph it.

The sea krait is adapted for the water by having a paddle-like tail which improves their swimming and the ability to hold their breath for 15 – 30 minutes underwater. With such a small head, you would be surprised to know that the males, whom are smaller, primarily feed on moray eels, while the larger females prefer the conger eels. The fact that they can eat eels larger than themselves dispels the old wives tail about not being able to bite a human. When they do find their prey they first paralyse the animal with their venom before swallowing it whole. One decent size eel can sustain them for weeks. Were we lucky to see three in one day or what? We haven’t seen any since.

So what has been our experience with this crazy creature? Tristan has seen a small one snorkelling off Taveuni Island in September. A couple of days later while Andrew and I were diving we spotted three. I followed one of them for quite some time and it was completely unfazed by me; it would stop have a look at me and continue in its search for food. The sea krait was gliding along and going in and out of caves and holes, which at the time I didn’t realise was it looking for eels. I honestly was very surprised to learn that they eat eels because like most people I thought they weren’t able to open their mouths enough to bite us.

Searching for eels, their main source of food.

While it is the first live encounter with a banded sea krait, back in 2011 when on Rah Island in Vanuatu we were fortunate enough to see a human version of the banded sea krait. On Rah Island they have a traditional dance called the ‘Sea Snake Dance’, which is the island’s Kastom dance and is only performed by men. The men paint themselves with black and white to mimic the stripes of the sea snake, carry a leaf in their mouths, sticks decorated with features and I think it was tomatoes.

We were fortunate to see and participate in it. You can see more at our post on Rah Island or here at Mota Lava. Here are a few photos from when we were there and much younger.

A few more interesting facts:

  • They typically lay a clutch of about 10 eggs, on land. The eggs incubate for about 4 months.
  • They are found in the Indian Ocean and the western Pacific.
  • The banded sea krait, like turtles, exhibit “philopatry” which means they return to the same beach to digest their food, rest and lay their eggs, similar to turtles.
  • Kraits or sea snakes differ from land snakes by their tail. Kraits have a flattened tail which acts like a paddle to aid in swimming.
  • Juvenile banded sea snakes spend more time in the water than on land, whereas adults spend about 50% of the time on land and in the water.
  • The banded sea krait, while able to live on land, moves at about a fifth of the speed than it does in the water.
  • They are preyed on by sharks, birds and larger fish and are particularly vulnerable when hunting among the coral.
  • Their tail is larger than their head, which sometimes confuse and fool predators.
Bye for now!

Information about the Banded Sea Krait was gained from the following sources: