The striking dadakulaci
We’ve all had embarrassing experiences.
It’s part of being human, but I seem to be particularly good at creating them.
But one stands out.
I had just arrived in Suva to teach biology at the University of the South Pacific.
Recently awarded my doctorate, I was brash and cocky (some claim I still am).
For some reason, perhaps to make up the numbers, I was invited to a diplomatic cocktail party.
I was single at the time and met an enchanting woman there.
Finding out I was a zoologist she mentioned she had seen a sea snake (dadakulaci) earlier in the week.
Eager to impress, I poured out my fountain of knowledge.
“Oh, they aren’t at all dangerous,” I said.
“Their teeth are at the rear of their mouth so they can’t really inject venom”.
And finally: “They aren’t able to open their mouth wide enough to bite a human anyway”.
As I looked into the eyes of my lovely companion to see if my profound knowledge had impressed her, a voice boomed from behind me.
“Everything you’ve just said is total bullshit.”
I turned around to greet the owner of the voice.
I writhe with embarrassment even now at what happened next.
“I have a doctorate in Zoology so I should know what I’m talking about.
“You should, but you don’t,” came the response.
“I’ve studied these sea snakes for twenty years, they are elapids, distant relatives of the cobra, armed with virulent venom, they are front-fanged, and they can open their mouth nearly 180 degrees.”
I turned beet red and walked away.
But in my total humiliation I had learned a valuable lesson – just because you believe something is true does not make it so.
The yellow-lipped sea krait, dadakulaci in Fijian and known to science as, Laticauda colubrina, is widespread in Fiji.
Unlike the hydrophiid sea snakes which are helpless on land, the dadakulaci spends around half of its time terrestrially.
After hunting they will return to digest their meal which may take days, depending in the size of their prey.
Presumably the warmer temperatures on land hasten this process.
They also come ashore to slough their skins and to mate.
Males are smaller than females and search out large females which can potentially produce more eggs.
But they seem more interested in length than girth.
Researchers Sohan Shetty and Richard Shine, built on earlier work by my friend Mick Guinea.
In an amazing display of scientific dedication, they camped on the island of Mabualau for three months in successive years (I hope they escaped to Toberua for a cold beer every now and then) and observed the mating behaviour of the snakes.
They don’t appear to have a particularly exciting sex life (the snakes, not the researchers).
Males cosy up to a female and lie on her, twitching occasionally.
Females may respond by raising their tail which opens the cloaca and if the male is quick, he can insert one of his two hemi-penes into the female and inseminate her.
Males don’t seem to compete.
Sohan and Richard observed no aggressive behaviour between them.
Females can lay up to ten eggs, but we know very little about where they are laid or how long the incubation time is.
Although the dadakulaci has a very wide distribution in the western tropical Pacific only two nests have ever been located.
Presumably eggs are deposited in caves or cracks in the foreshore above tidal influence.
Dadakulaci exhibit strong philopatry (love of place).
Snakes shifted to another island 6 km away always returned to their home island.
Males are considerably smaller than females which weigh three times more on average.
This substantial sexual dimorphism leads to differences in food and hunting behaviour.
Females tend to swim further and dive deeper, mostly preying on conger eels while the males feed primarily on morays.
Subduing a moray or a conger eel and then manipulating them to swallow is no mean feat.
This is where that toxic venom come in.
In places where the banded sea krait, Laticauda colubrina, is common, morays have evolved substantial resistance to their bite.
Harold Heatwole and Judy Powell (1998) tested moray eel resistance to injection with dadaculaci venom.
They found that species that coexisted with the snakes were highly resistant.
The liver-coloured moray Gymnothorax hepaticus and the undulated moray G. undulatus withstood massive doses (75mg/kg and 42.5 mg/ kg respectively).
Caribbean spotted morays, Gymnothorax moringa, which evolved in the absence of sea snakes, were extremely sensitive and died at
doses of only 0.1 mg/kg.
The authors comment “Snakes were collected from sea caves, transported in cloth bags to a local hotel where venom was expressed into vials” – you just have to love biologists.
The yellow-lipped sea krait carries out cooperative hunting on some reefs in Indonesia.
The snakes link up with goatfish and jacks.
When prey, spooked by the predatory fish, enter holes and crevices in the reef, the snakes go in after them.
Apparently all three of the species involved do better hunting cooperatively than individually.
This amazing phenomenon was brilliantly captured in Sir David Attenborough’s, Planet Earth: Shallow Seas documentary.
I really like dadakulaci.
They are so mellow and it is always a dive highlight when I encounter one.
Their forked tongue flickers in and out, tasting the water, as they search for prey.
Promising leads are investigated by swimming into the crevice or small cave.
They are vulnerable at this time but wave their tail around as they are investigating.
Supposedly the flattened rear portion of the tail resembles the head, thereby discouraging potential predators.
Not sure I buy it.
My most memorable, and slightly disconcerting dadakulaci encounter was in the Namena lagoon.
I had just finished my safety stop when a very large (1.5m) female swam up to me and ran the tongue test all over me.
Apparently satisfied, she then coiled herself around my left leg.
I waited a few seconds then looked down.
She seemed totally at home here and in no hurry to disentangle.
I used my other leg to slowly swim to the dive boat, my camera housing in my hands expecting her to disengage.
She didn’t.
After handing up the camera I gently unwound her and she swam slowly off.
Have a great week.
Keep smiling.
• PADDY is the author of Fiji’s Natural Heritage and a former contributor to The Sunday Times. He taught at USP for many years and now works as a personal trainer and university professor in Denver, Colorado. Dr. Ryan is a PADI divemaster and a professional photographer whose work and articles have been published around the world. He is madly in love with Fiji and returns whenever he can.
