Close Encounter with a Bimac

By Karen E. McReynolds

It had been a glorious day.  Our whale watch excursion in the morning was exhilarating and yielded enough migrating gray whales to satisfy.  After a picnic lunch on the wharf, we drove a little further down the Monterey peninsula to placid Pacific Grove, home of migratory monarch butterflies as well as fabulous tide pools.  It was not the season for butterflies, but tide pool creatures are impervious to terrestrial seasons; they remain year round, so off we went to see what we could discover.  All of these natural treasures were new to my non-major general biology students, and they were easy to impress this day: perfect weather, great creatures of the deeper sea, and now smaller creatures of the rocky shore.

I had selected a date that offered us a minus tide in the afternoon, and the tide pool creatures were abundant.  As our time drew to a close, I gathered all the students together so we could compare notes and assemble our organism count for the tide pools.  In reviewing the list of hoped-for organisms that I had prepared ahead of time, I noticed that there were a few that we had not seen.  This wasn’t surprising – after all, it’s not the Discovery Channel, as I frequently remind students – but it was still a bit disappointing.  Secretive habits, camouflage, and nocturnal preferences successfully hide some creatures from curious humans quite effectively.  One of these was the Two-Spotted Octopus, Octopus bimaculoides, referred to in marine biologist’s slang as a bimac.  This is not a rare denizen of the rocky shores along the eastern Pacific, but they hide well and prefer darkness, so they are not easily observed.   I had only seen one of these on one previous tide pool trip, and it was a fleeting glimpse: a small cephalopod, immediately zipping out of view and into a crevice in the rock underwater, where it steadfastly remained.  On this day, however, we had indeed seen a good variety of organisms, so our time at the tide pools had still been valuable. 

Within seconds of my comment lamenting the absence of a Two-Spot, one student blurted out, “There’s an octopus!” And lo and behold, we all looked down at the small pool he was standing in front of, and there was indeed a slithery octopus, heading to the deepest edge of the tide pool to hide.  Impulsively, the student poked at the general direction of the creature with the point of his pencil, and then the fun began.  This octopus, unlike the shy specimen I had seen on a previous trip, was apparently an extrovert.  He or she scuttled across the tide pool, shooting a stream of dark brownish ink as it went, and headed up toward the surface at the opposite end of the pool.  When it got there, it ascended the rock surface with no hesitation and climbed right out of the water.  I can only describe its terrestrial mode of movement as “schlooping,” a word I admittedly made up on the spot, but it seemed to suit the creature well.  The octopus schlooped up the rock out of the pool and across a bed of barnacles, skirted a clump of greenish algae, and crossed a fair amount of red-brown rock before it descended into another more satisfactory tide pool.  As it moved over each different background, its color changed instantly so that it always matched its surroundings.  Its total journey out of the water, as witnessed by a class of gaping students and their equally astonished instructor, was about five feet.  It disappeared into the depths of its new tide pool residence shortly after its arrival and didn’t make any further appearance.

What a show! This creature of the not-so-deep gave us a tiny glimpse of creation that none of us had experienced before.  And what perfect timing.  The Psalmist says, “Yonder is the sea, great and wide; creeping things innumerable are there, living things both small and great.” (Psalm 103:25)  None of those students will ever think of “creeping things” in the same way. 

Thus, we learn the value of field trips.  Textbooks and lab assignments are not the only materials that come to life once we leave the classroom.  Nature provides illustrations of scripture as well: in this case, a small, schlooping thing, rainbowing its colors as it scuttled through our lives.   

Related reading: Notes From Ms. Frizzle (1)