Subsurface Superpowers

Imagine how much more you could get out of a holiday at Hadahaa if you didn’t have to sleep. Honeymoons would be 30% longer; you’d be able to catch a glimpse of every shooting star and gaze at every sunrise or, if you are as obsessed as me, snorkel throughout the night. Sound unbelievable? Not so for a dolphin; amazingly all cetaceans have evolved the ability to stay awake throughout the day and night by sleeping with only half of their brain at a time. Unlike most of us, they must consciously take each breath which essentially means they can never completely fall asleep. It’s a useful skill, and got me thinking about other enviable abilities there are in the underwater world:

Invisibility

Fancy blending into to the background in an instant? Then consider life as one of our Hadahaa locals - the Octopus cyanea.

 There are some pretty impressive disguises out there, but Cephalopods really take the biscuit because they are not stuck with just one look; they miraculously transform the colour, pattern and texture of their skin to perfectly match with their surroundings. Layers of different pigment cells expand or contract upon demand to alter the balance of colours. On top of that, they have tiny muscles which tighten to form perky little peaks. And if all else fails, they use their jet propulsion and disappear with a puff of ink.

Octopus Images from Roger Hanlon (hermes.mbl.edu/mrc/hanlon/coloration.html)

     

 Immortality

Feeling a bit senile? If you were coral you could simply copy yourself and start again, and why stop there? Multiply into a colony and continue on for hundreds of years. 

Once a year, coral polyps have a brief sexual outburst, but for the rest of the time they make do with the realms of asexuality. Genetic clones bud from a parent polyp once it has reached adult size. A degree of connectivity remains between individuals allowing the sharing of nutrients and combined structural support.

Glow in the dark

Why waste money on lighting schemes when you could emit light from within?  Glittering microscopic plankton glow with a blue-green light when disturbed at night.

These little protists and copepods in the waters around Hadahaa contain a special substance called Luciferin which produces light in a chemical reaction with oxygen.  Although this enchanting habit makes them more obvious to us, it’s actually a defence mechanism. The sudden flash of light can confuse predators or cause them to feel vulnerable; like a call to reinforcements, it alerts even bigger hunters that there’s a potential meal nearby.

Telepathy

Decisions are hard, wouldn’t it be nice to instinctively know what everyone else is doing, and automatically do it too? Then think about trading places with the bait fish who love schooling around the island at this time of year.

A combination of sight and acoustic vibrations keep the discipline within schools, allowing all the fishy students to move, turn and swim with perfect cohesion. Fish prefer to stick with others about the same size with all of them keeping on average a distance of 0.7 body lengths apart.  There are no leaders of the group; the ones at the front frequently switch places when they change direction or scatter then re-group. There are many advantages of schooling; an obvious example being that hundreds of eyes are on the lookout for danger, or predators becoming easily confused during a chase, not knowing who to single out for supper. 

Frolicking with Dolphins

As you would expect from a marine biologist, I’m in and out of the water and a bit damp quite often. Therefore you would have thought that I’ve learned by now not to take my phone with me, sadly this is not the case. Thankfully my most recent phone-drowning hasn’t dampened my mood. The incident was due to an impulsive dive off the end of our jetty, so I could swim amongst a pod of twelve bottlenose dolphins. At that moment my mobile phone didn’t register as being significant compared to an interaction with wild dolphins splashing around in the sunset. If only all the others had been so glamorously sacrificed. 

I know I’m not alone in having an overwhelming adoration for these extraordinary animals. Dolphins are second only to humans in their brain to body ratio, and although intelligence is notoriously hard to determine, it’s obvious that dolphins are up there. Their social behavior is complex and fascinating, as is their communication. They can differentiate, as well as produce, a massive range of sound frequencies, ten times more than humans. One of the most magical things about being underwater with dolphins is that you hear them conversing with one another. Research has shown that each individual has their own signature whistle so they can all recognize who said what in the group. Because sound travels so well through liquids, their chatter penetrates your whole body and you feel completely encapsulated by an orchestral mix of of high-pitched squeaks and clicks. One of our guests likens it to being at the dentist, although I hasten to add that of course, it’s infinitely more enjoyable.

I love to see animals in their natural habitat, but there is no doubt that we have to be careful not to disrupt the natural flow of things, or even worse inadvertently damage the very thing we are trying to catch a glimpse of. The wonderful thing about dolphins is that they appear to actually want to spend time with us. Our Dive-master and true animal lover Rilwan, is very proud of the fact that a dolphin has once tried to kiss him. I unfortunately don’t seem to have quite the same level of appeal, although on every underwater encounter the dolphins have playfully swum closer to get a good look, disappointingly I’ve clearly never made the cut.

Dolphins around the Maldives have conveniently predictable daily routines, which is handy for us. We take trips out to spot them at sunset; at this time of day they’re leaving the safety of the shallow water within the atoll for the open ocean. They tend to rest during the day, and in the evenings they’ll met up with friends forming two hundred strong pods, embarking together on overnight fishing sprees. The most common species here, the spinner dolphin, is particularly fun to watch. They are one of the smallest and the fastest dolphins, having been known to swim at speeds up to an incredible 55km/hr. When in the mood, the spinners can swim at full speed to towards the surface, jumping up and rotating on their tail as many as seven times in one leap. This spectacular acrobatic airshow is not well explained; it could be a form of communication, a method of removing parasites or simply for kicks and giggles. Either way, it looks like a lot of fun, and always results in shrieks of pleasure from all of us on the boat. Every time I take our guests out on a dolphin trip I’m reminded of how lucky we are to live in a remote area so unblemished and abundant in natural wonders.

Frolics with a friendly spinner dolphin