Hi, I'm Jonathan Bird and welcome to my world!
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The sea snake is an animal surrounded in mystery—known for its incredibly powerful venom, but not
much else. Just how dangerous are these marine reptiles?
I have traveled to Queensland, Australia on a quest to learn about sea snakes.
Here on Australia's Great Barrier Reef, sea snakes are fairly common. Lets go see
if we can find one.
I hit the water, grab my camera and head towards the sea floor.
Today I'm diving on a little seamount called a coral Bommie. It's a mini-mountain of
coral sticking up from the bottom, but not quite reaching the surface.
Near the top of the Bommie, thousands of small fish feed on plankton passing by in the current,
but they stay close to the reef, because they are being watched by a big school of jacks
who are on the prowl for food themselves.
The bommie is covered in healthy coral that provides lots of nooks and crannies for the
fish to hide if they need cover.
On the other side of the bommie, a large school of snappers are also looking for something
to eat, and keeping a safe distance from the jacks.
As I swim along at the base of the bommie, I'm keeping my eyes open for a snake-like
animal. The coral looks healthy and a Spinecheek anemonefish gives me a quick glance from the
safety of her host anemone.
But I keep scanning the bottom and at last I have found my quarry: an olive sea snake,
the most common species around the Great Barrier Reef. It's swimming along the bottom doing
the same thing everything else is doing—looking for food. The sea snake is closely related
to a land snake, except it has adapted for life underwater.
When a sea snake flicks its tongue, it's getting rid of excess salt secreted by special
glands in its mouth. Sea snakes live exclusively in the ocean, but since they're reptiles,
their kidneys can't deal with too much excess salt in their blood.
A sea snake gets around with a flattened section of tail that looks like an oar and serves
as a fin. It looks just like an eel when it swims, undulating its body and getting propulsion
from that flattened tail.
Although sea snakes prefer to eat fish, eels and shrimp, these snappers aren't at all
afraid of the sea snake, because they are way too big for the sea snake to bite.
This snake is heading for the surface to grab a breath of air. A sea snake, just like a
land snake, has lungs and must breathe air to survive. It can hold its breath up to 3
hours during a dive. Recent research has shown that some sea snakes also can absorb a little
bit of oxygen directly from the water through their skin, which is probably why a breath
can last so long.
After spending a minute at the surface breathing, the sea snake comes back down to the bottom.
It's poking around, looking for holes where it might corner a fish or shrimp. It sticks
its head into the holes, hoping to get lucky.
The sea snake is most closely related to the Cobra on land, and its venom is quite similar
to cobra venom, but considerably more potent. If it manages to grab a fish, the venom will
kill it in seconds.
Sea snakes quite often take a rest on the bottom, sleeping as they hold their breath.
I use the opportunity to sneak up on one. In spite of their fearsome venom, sea snakes
are very timid and not particularly aggressive. Although this one is obviously not thrilled
about being picked up, it doesn't try to bite me.
And when I let go, it just swims away.
away.
I find another one and can't resist the opportunity to show the flattened tail section.
Swim, be free!
Although the sea snake is one of the most venomous animals in the world, you're not very likely to
be bitten by one.
There are 62 known species of sea snakes and they live all around the tropical Indo-Pacific.
I found this banded sea snake in the Philippines. They like nice warm tropical water because
they are cold-blooded, like all reptiles. If the water gets too cold, they get lethargic.
So, no matter what you might think of snakes, sea snakes are timid and shy animals that
represent almost no threat at all to people, even though they produce some of the most
powerful venom in the world.
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