Thursday, October 13, 2011

Fish that use tools!

Jane Goodall shocked the world in the 1960's when she reported the use of tools - that is, the manipulation of an inanimate object to more efficiently alter the position or shape of another object - among chimpanzees.  The belief that this was an exclusively human behavior had been debunked.  Since then, reports of animals that use tools come from all over the animal kingdom - though usually among the more highly-evolved species in each group.

Orange-spotted tuskfish, Choerodon anchorago
In September, an article in the scholarly journal Coral Reefs caught my eye.  Dr. Giacomo Bernardi of the University of California' Long Marine Lab was on a trip to Palau when he noticed and filmed an orange-spotted tuskfish (Choerodon anchorago) smashing a clam against a rock to break it open (video link).  To the eyes of a trained ecologist, that rock was an 'anvil,' a tool being used by the wrasse which would otherwise have a very hard time getting a large bivalve shell open.  It is not the first report of tool use among fishes - indeed a report from the Florida Keys describes the same behavior in a yellowhead wrasse (Halichoeres garnoti) as early as 1995.  In addition, the use of a stationary rock as an 'anvil' may be stretching what is classically considered tool use, since the fish doesn't manipulate the tool.  But Dr. Stéphan Reebs of the Université de Moncton points out that there are a couple other interesting examples of "tools" manipulated by fishes - such as a damselfish species (Stegastes leucoris) that cleans algae off a rock for egglaying by spitting sand at it, and a freshwater cichlid (Bujurquina vittata) that lays its eggs on a leaf and will carry the leaf with it when fleeing a potential predator.  Studies of tool use are important because the behavior may indicate a higher form of intelligence - a somewhat subjective biological concept - and thus give us clues to the evolutionary history of cognition.

Of course, your heroic author had also seen this behavior in the wild.  On one of my last trips in the Red Sea before graduating with a Master's degree, I was diving about 30 feet deep on a beautiful sandy patch of reef.  I was helping to fence off a clean, square sand patch for an experiment and had to move a rock out of the way.  As soon as I moved the rock, a scallop darted away.  (Scallops do have eyes, and they can close their shell in rapid succession to effectively jettison themselves backwards, away from potential predators.)  Of course, a tiny red scallop swimming over a white sandy bottom instantly signaled a feeding opportunity to motion-wary fishes nearby, always hungry on the coral reef.  Perhaps wrongly, I decided to sacrifice the scallop for science to see what behaviors it would elicit among the diverse community of fish species waiting to attack.  Much to my surprise, a checkerboard wrasse (Halichoeres hortulanus) immediately darted in for the meal - despite the fact that it was far too large for this fish's tiny mouth!  To my further surprise, it swam around with the scallop in its mouth and began striking it against various rocks, likely to break it and make it smaller to eat.  Lucky for me, I caught it on video (watch it full screen to catch the anvil use)!

When I saw Dr. Bernardi's article, I wrote him and discovered that this was potentially the first observation of this behavior for this Red Sea wrasse.  These wrasses do not regularly feed on scallops, yet this individual was behaviorally prepared to accept the challenge.  Would it need to learn this technique?  Clearly it made the choice to do something about the large size of the scallop instead of just rejecting it outright.  And if smashing food on an anvil is not a regularly used behavior, when would the fish have learned how to do it?  It is amazingly difficult for scientists to record these rare behaviors since air supply and funding limit our underwater observations to mere snapshots of time in the lives of these wild creatures.

Saturday, October 8, 2011

Finding Nature Around You: The Hickory Tussock Moth

Moving back in with your parents to work from home means that there are always domestic projects they can find for you, the perceived new help.  Today I had to change the lawnmower blade and cut the grass.  I had just removed the blade from our electric mower and was walking back into the basement with it when a white and black fuzzy furry caterpillar started wriggling across the path in front of me - right by my basement door!  It seemed on a mission - it was moving very quickly for a caterpillar.  Fascinated, I dropped to my knees and coaxed it to crawl on the mower blade I was carrying (so I wouldn't lose sight of it - it was moving ever so fast for a caterpillar).  I then ran into the house to find my camera, cautiously watching the caterpillar to avoid dropping it.  (I also did not want to touch it - the setae of caterpillars, marine worms, and other "furry" invertebrates tend to break off in skin and itch, like fiberglass.)  This was a very interesting situation for my mother, who was entertaining a house guest.  I am curious to know what they must have talked about when I asked her to hold the lawnmower blade and watch the caterpillar while I ran upstairs for my camera!

With camera in hand, I returned the caterpillar to where I found it on the ground outside my basement door.  I then flopped down on my stomach and started shooting.  I purchased my camera for the purpose of photographing wildlife, mostly for identification but also to try to capture some unique and emotive shots.  But unique and emotive are not always at your control, especially if you've decided to not manipulate your subject.  I didn't think it right to capture this creature; it clearly had somewhere to be!  So I did the best I could as it crawled towards me, pattered through the garden, and trudged through a miniature forest of grass.

This little caterpillar is not afraid of my hand!
After it had crawled off into the bushes and I lost sight of it, I ran inside to identify the beast.  This can be a very tricky task, requiring your memory, photographs, the internet, field guides, or a biologist with local expertise.  Google is my first starting point - not because it is the best, but because I am impatient.  Lucky for me, the first (non-advertisement) link Google returned for "caterpillar identification guide Massachusetts" took me to an excellent caterpillar guide on, where I could search for caterpillars that had certain identifiable attributes.  Noting that this caterpillar was "yellow/white" in main body color and had "hair pencils" or "lashes" of hair (tight groups of longer setae that look like eyelashes), I cut down the pool of potential species to a few and by looking at pictures quickly identified the beast as a hickory tussock moth caterpillar, or Lophocampa caryae.  

The adult moth.
Using the scientific name like a key for unlocking a wealth of knowledge, I re-searched Google (ah, so that's where "research" comes from?).  The species is named after its preferred food - hickory tree leaves - and its hairy groups of setae, or "tussocks."  It is also known to feed on walnut and butternut trees, as well as beech and oak.  These fascinating creatures complete their life cycle in a single year!  Adult moths take wing, mate, and lay eggs from May to July.  The developing caterpillars are out and about from July to late October, when they start looking for a place to "coccon" overwinter and metamorphose in the spring.  And perhaps statistical probability explains why I had the fortune to come across one, for this year appears to be a boom year for this species.  Indeed the paradox of nature is that it is in constant fluctuation - wars waged between predators and prey means species may be rare some years or decades but common the next.  What a system all the non-human species must still contend with!

For those of you that think you don't have time for nature or that you could never see such creatures that I run into, I maintain that the majority of times I see these wonders when I am least trying to find them.  After all, the hickory tussock moth caterpillar wasn't a yard from my door!  This does not make me special or unique - what wonders lie in front of your door?  Instead, discovering the nature around you is more like playing a musical instrument, where practice makes perfect.  One skill involved in this is noticing subtle movements.  Generally, if some object is moving of its own free will, it might be alive.  So once you've gone looking for lots of wildlife and start getting used to spotting moving creatures, those same subtle movements will catch your eye when you are not looking but are still in the right place.  We all share the ancestral tradition of hunting, we have just forgotten how.  Re-awakening your spotter instincts brings with it a very fulfilling sense of belonging to your wilderness, even if you only noticed a caterpillar that wouldn't make a good meal!  ;)

Monday, October 3, 2011

Wild edibles of New England

Today I visited the Oak Knoll Wildlife Refuge in Attleboro, Massachusetts for a combination talk plus walk about edible wild foods.  Finding food in the wild, or 'foraging,' is an activity many Americans do, though it is easily overlooked.  If it sounds strange, consider that hunting and fishing are really just foraging for animals - and that all of our farmed foods were once exclusively wild.  (And we once exclusively foraged.)

Russ Cohen sharing wild food knowledge
Russ Cohen, author of Wild Foods I Have Known... and Eaten guided our three hour adventure.  He brought along with him some fruit "leather," an all-natural snack he makes by simply mashing the berries of the autumn olive (Elaeagnus umbellata) and drying the pulp in thin (1/4") sheets in the oven.  No other ingredients needed! And you can feel good about eating them to extinction - they are an invasive species!

Sheep sorrell (Rumex acetosella), a lemony salad green!
Russ introduced us to many other wild edibles that day, including boletes, chanterelles, and sulfur shelf mushrooms, sheep sorrell (excellent tangy salad greens), black walnuts, hickory nuts, strawberries, blueberries, blackberries, grapes...  It was hard for me not to start tasting everything at random!  There are plenty of wild plants that do not make good foods so I would suggest getting a guide to foraging in your area, like Russ' book, before cooking up some lethal mushrooms.  Although the talk cost me $18, it all went towards wildlife conservation and I had a great time!

Some beautiful but INEDIBLE wild mushrooms