Mystery underwater sand circles are actually puffer fish art

If you thought crop circles were strange, odds are you haven’t seen these:

crop circles

The underwater version of crop circles!  Some of the intrigue with crop circles faded once people stopped thinking they were made by aliens, but these sand circles are even more interesting to behold once you know where they do come from.

So who or what makes these enigmatic sculptures where they are doomed to fade into nonexistence once the ocean erodes them away?  No, not an alien race, nor a group of people from of the legendary Atlantis, but Puffer fish!

Male puffer fish craft their detailed sculptures by using a single fin to push the sand around, working day and night to finish the job, topping it off by cracking shells and placing them along the inner grooves of the circles.  Similar to bower birds, the puffer fish creates these structures to attract females.  However, the marine art serves a greater purpose than to look pretty to impress the ladies.  The puffer fish constructs his art with great care because it will become a nursery ground for his future offspring!  Watch him here:

Once the female has found the grooves, she will follow the ridges to the male in the center, mate with him, and lay her eggs.  The more ridges the circle contains, the more likely it is that the female will mate with the male, because she knows that the ridges will buffer the eggs from currents, thereby protecting the eggs from disturbance and exposure to predators.  Furthermore, the seemingly decorative seashells provide nutrients to the eggs and newborn puffer fish.

The artist at work

The artist at work

Next time you get annoyed by the sand that gets in every orifice after a day at the beach, or think humans are clever for using sand to make glass and concrete, think about how the puffer fish makes art out of sand to attract females, protect its young, and provide sustenance to its offspring just by using the raw stuff-and you might find new appreciation in sand, and the ingenuity of animals, a little more.

References:

Discovery: http://news.discovery.com/earth/oceans/puffer-fish-makes-elaborate-undersea-sand-circles-120925.htm

This is Colossal: http://www.thisiscolossal.com/2012/09/mysterious-underwater-crop-circle-art-discovered-off-the-coast-of-japan/

From Marlin to Marilyn: Clownfish Change Their Genders! Bizarre Courtship and Mating Rituals in the Animal Kingdom

Clown_fish_in_the_Andaman_Coral_Reef

Clownfish in anemone home

It turns out Finding Nemo had it wrong.  When a barracuda ate mom in the first scene of the movie, Marlin would not become a single dad, because being a single dad clownfish is impossible.  Realistically, Marlin would have become Marilyn– a single mom!

Clownfish are protandrous sequential hermaphrodites.  In other more pronounceable words, clownfish start their lives as males and then change into females.  Why is this necessary?

Clownfish2

Clownfish live in sea anemones and have adapted so they are unharmed by the anemone’s stings.  Because of its unique mutualistic relationship with the anemone (the clownfish eat parasites off the anemone, effectively cleaning it), the clownfish is reluctant to wander too far beyond its tentacly home.  This becomes problematic when the clownfish wants to meet members of the opposite sex, so the clownfish has evolved an interesting mechanism – sequential hermaphroditism – to overcome this obstacle.

Nemo

Marlin and Dory from Finding Nemo movie

Instead of braving the dangerous open waters beyond the reef (no, neither Marlin nor Nemo would realistically breach the “drop-off” and make it back alive), all the clownfish living in one place are males except the oldest, which is always a female.  After the head female dies, the next-oldest male turns into a female!

I suppose Pixar would’ve had a hard time explaining why they turned Marlin into Marilyn after one scene – I would’ve been confused too.  But in reality, the animal world of romance hosts a plethora of bizarre courtship behaviors, mating rituals, and other such oddities that put human courtship to shame!

References:

Clownfish picture 1 by ecatoncheires on Flickr: http://www.flickr.com/photos/ecatoncheires/2335044473/.

Nemo picture: from Cthomasuscg on Flickr:  http://www.flickr.com/photos/cthomasuscg/3304908183/

Interesting animal romance behaviors:  http://www.care2.com/greenliving/animal-romance-they-have-sex-how.html?page=1.

“Sequential hermaphroditism.”  Wikipedia.org:  http://en.wikipedia.org/wiki/Sequential_hermaphroditism

Clownfish information at Shedd Aquarium:  http://sea.sheddaquarium.org/sea/fact_sheets.asp?id=72

Clownfish information at Visit Sea Life:  http://www.visitsealife.com/explore-our-creatures/clownfish.aspx

Clownfish information at Evolution Faq:  http://www.evolutionfaq.com/articles/sex-change-nature-coral-reef-fish

Sea Otters: Adorable, Endangered, and A Keystone Species

Here_I_am.. sea otter baby sea otter

This cuddly creature is a sea otter, or Enhydra lutris, a well-known marine mammal native to the coasts of the northern and eastern North Pacific Ocean.  This furry, playful fellow is more than just adorable, however.  Otters are a keystone species.

In architecture, the keystone at the top of an arch holds the arch together.  Without the keystone, the whole arch and building surrounding it will collapse.  Similarly, some species of animals are called “keystone species,” meaning that a whole ecosystem, or interplay between living organisms and their surroundings, depends on that particular species to keep it running smoothly.

tumblr_ma95mbDj261rt5smro1_500

Sea otters play a crucial role in their watery home.  How do we know?  Here’s the story:

In the 1700s, sea otters along the coast of California were hunted nearly to extinction for their furs and killed by fishermen who thought they were eating too much of the fish they wanted to catch.  When the otters disappeared, the animals they normally eat, sea urchins, enjoyed a large population boom.  Soon, there were so many sea urchins that they ate all of the kelp, a type of seaweed, at the bottom of the ocean, and caused an “urchin barren” to form, which means that the ocean floor is scraped clean and becomes an “ocean desert” in the ocean that is essentially devoid of life.  This is bad!  Fish raise their young in the protection of the kelp and other animals hide it in to avoid prey, and all those animals began to flee the scene as well. The fishermen now had less fish to catch, not more.  It turns out the otter was playing a much more crucial role in this ecosystem than people previously knew.

What happened to the otters?  In 1911, a treaty was passed to protect the sea otters from being hunted.  In some places, the populations of sea otters recovered, and eventually so did the kelp and fish.  But there are still some areas that have suffered near-permanent damage from the removal of just one type of animal – the sea otter – from its home.

Now, the sea otter is globally an endangered species, meaning that its numbers are so low that it is under imminent threat of becoming extinct, or dying out entirely.  The sea otter’s story shows us that if we take action we can achieve a remarkable success story that seems daunting, if not impossible, at first.

Sources:

“Here I am..” Top left photograph.  Photograph taken by Alan  Wolf and distributed under a Creative Commons License: CC BY-NC-SA 2.0

Baby sea otter photograph: sflo1822 on tumblr.

Three otters photograph: jamoore52 on tumblr.

Seat otter:  http://en.wikipedia.org/wiki/Sea_otter

Keystone species (definition): http://animals.about.com/od/animalswildlife101/f/keystonespecies.htm

Keystone species hypothesis: http://www.washington.edu/research/pathbreakers/1969g.html

Keystone species empirical evidence:  http://rspb.royalsocietypublishing.org/content/early/2012/07/03/rspb.2012.0856.full