Raccoons’ Amazing Use of Water

 

Flora and Fauna Fridays

A weekly entry about the life of our estuary and watershed.

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by Erik Baard

HarborLAB volunteers (including a little one, Lily) recently spotted snow tracks at the GreenLaunch. Not our usual guard cat prints. The fingers weren’t webbed. At first we thought we might have fresh evidence of our resident muskrat. The tracks led up and down our growing native habitat slope from the water to the uplands, so that made sense. Ah, but there was no tail line. That leaves us with raccoon!

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Similar animal tracks. Credit: Lawrence Wade, The Old Naturalist

 

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Raccoon forepaw. Credit: Gaby Muler via Wikimedia Commons. 

The lack of webbing is very unusual for mammals in the order carnivora. What makes raccoon paws absolutely unique, however, is their sensitivity. More than 60% of the sensory perception areas of the raccoon’s cerebral cortex is given to touch. A raccoon’s dexterous fore paws are covered in tiny sensory spikes. The density raccoon pressure sensitive cells (called mechanoreceptor cells) is quintuple that of most mammals, matched only by primates like humans.

The primacy of their fore paws is reflected in the species’ names, including proto-Algonquin via Powhatan ahrah-koon-em (“one who scratches or rubs with its hands”) and part of the Latin one given by Carl Linnaeus (lotor or “washer”). The myth that raccoons wash their hands or food is rooted in amateur observations of their actual use of water: when submerged the sensory micro-bristles soften and become even more sensitive. A raccoon dips objects in water, fully submerging its paws, to even more acutely feel its surfaces. This video of a raccoon accidentally dissolving his treat of cotton candy is for only the most stone-hearted.

Even prolonged time in cold water doesn’t seem to diminish this sensitivity. Naturally this helps them to find small creatures, eggs, and some plants to eat in aquatic or muddy environments. Their fur is also well adapted to repel water.

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Once raccoons have learned of food sources, they won’t soon forget. In laboratory tests they remembered complex tasks for years afterward. Their ability to recall, problem solve, and think abstractly ranks them with Rhesus monkeys in evaluations of animal intelligence. So, say hello to our smart new neighbor! Maybe a furry new volunteer?

Worrying Dawn of the Blue Era

Water Wonk Wednesdays

A weekly column on water news, tips, and innovations.

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Erik Baard at Hallets Cove in 2015. Photo by NYCDEP for HarborLAB. 

by Erik Baard

The East River has so far rolled through this winter unadorned by a white speckling of sea ice (photos here are from 2015). On the Hudson River, bald eagles and seals have no ice floes to ride from the foot of the Palisades to the skyline. HarborLAB volunteer Thomas Dieter, director of CUNY Start at LaGuardia Community College, relays his observations from his home in Hunters Point South:

“We haven’t spotted ice yet this winter, and at this point I’m guessing we won’t. From our apartment at Hunters Point South Park, we can see that the inlets and coves just north of Newtown Creek haven’t iced over. In the past, the inlet where the ferry docks and the cove south of the fishing pier iced over at some point–but no such luck so far this year that we could see…The water in these areas doesn’t move as quickly as the river, and it’s far shallower, so I expected ice to collect there again this January and February.”

Our local disappointment echoes the vanishing polar sea ice aspect of the global climate change crisis, though some seek to take advantage of it for undersea fuel extraction, military maneuvers, and shipping. The National Oceanic and Atmospheric Administration’s Arctic Report Card on sea ice, glaciers, snow cover, temperatures, indigenous cultures, and animal health is profoundly grim. A special concern is ocean acidification in the Arctic, which is undermining the regional ecosystem’s less diverse food chain.
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Scientific American/Climate Central report that winter sea ice at both poles has retreated to record lows. This is a sharp reversal from a record Antarctic peak last year, but a continuation of a trend of historic lows in the Arctic. Ice sheets ashore — notably in Greenland — are shrinking and thinning too. Winter heat waves are lashing the Arctic as warm air pushes north.
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Gantry Plaza State Park in 2015. Photo by Mark Christie, Hunters Point Parks Conservancy. 

Naked Gobies in Newtown Creek

Flora and Fauna Fridays

A weekly entry about the life of our estuary and watershed.

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Naked Goby. (Smithsonian Environmental Research Center.)

 

by Erik Baard

Skinny dipping in the Newtown Creek Superfund Site might seem unwise, particularly in February, but it’s a way of life for naked gobies (Gobiosoma bosc). These very small, bottom-dwelling fish of the Eastern Seaboard and Gulf states are extremely common yet rare to see. That’s a shame because gobies — one of the most diverse families of fish, with over 2,000 species — have rich and fascinating lives packed into typically less than four inches and four years.

Ecologists for city, state, and federal agencies did encounter naked gobies in early studies to profile the life and pollutants of what became HarborLAB’s home waterway. They discovered an abundance of goby eggs at the mouth of the creek but not further in, indicating that spawning happened where cleaner East River waters swirled in with each tidal cycle. No surprise given that naked gobies and their eggs and spawn are often found in the fish-protecting screens covering intake tubes at the nearby Ravenswood Power Plant. Bear in mind, however, that this is opposite of the natural state of affairs. Fish normally lay eggs and spawn in sheltered areas outside the swift main channel of waterways. The East River is dredged, constricted by landfill, and edged with bulkheads that make for even faster currents. The slower-moving four-mile stretch of the Newtown Creek should by rights be the East River’s nursery.

As it is, only adult “gobies were prevalent in the mid-section of the Creek,” according to the Fish and Wildlife Service report linked above. Still, what a testament to this species’ hardiness, given that the creek bed (commonly described as being like “black mayonnaise”) is sedimented with toxins and stripped of naked gobies’ natural habitat of oyster beds and salt grass clusters. Females prefer to lay their amber-colored eggs into empty oyster shells. In the Newtown Creek, they make do with rock, crumbled concrete bulkheads, partly interred plastic trash, bottles, and other debris. In the winter, they bury themselves into that poisonous black mayonnaise.

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(South Florida Water Management District)

Naked gobies feed on worms and small crustaceans, which concentrate in their tissue the toxins of a century of oil spills, refinery and tannery effluents,  and illegal dumping.  Cloaked by the muck and the murk, these “naked” prey fish for better known species like striped bass, eels, and bluefish are still taking no chances. The species is scaleless and camouflaged in green and brown blotches. Their eyes are close together, atop the head. At a glance they look like lizards. The young are translucent.

Naked goby pelvic fins have evolved to fuse into suction cups, a neat trick for anchoring themselves. Scientists have noted that gobies can remember how to navigate complicated obstacle courses for at least 40 days, and judge and remember spatial relationships, useful for hopping from tidal pool to tidal pool. Some cousin species of goby have also evolved complex behaviors and symbiotic relationships. For example, one species climbs waterfalls that to human scale is the equivalent of climbing Mt. Everest three times over — check out this video! Others groom the parasites off larger fish. Another enjoys an “Odd Couple” relationship with a large burrowing shrimp. The fish and crustacean cohabitate and deposit eggs in the same burrow. They touch each other (with tail and antennae respectively) constantly to know if the other is agitated or retreating, relying on each other’s complementary senses. And we are still discovering new species of goby!

 

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Naked Gobi range. 

A Night for Snow Pillows

Water Wonk Wednesdays

A weekly column on water news, tips, and innovations.

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Snow Pillow monitoring station. Photo by NYCDEP 

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SNOTEL with snow pillows. Image by USDA/Natural Resources Conservation Service

The term “snow pillow” evokes a peaceful, muffling moonlit whiteness spreading a lull across the countryside. For New Yorkers, however, it’s a critical piece of hardware.

Much of the billion gallons of water used daily by nine million residents of NYC and surrounding counties arrives as snow. The white caps of the old, rounded Catskill Mountains nestling the Neversink Reservoir are a reserve bank that melts to meet our needs in warmer months. Snow melt can also swell rivers, so anticipating flood risks is very important to towns an farms. With so many lives affected by snow, the NYC Department of Environmental Protection, in partnership with City University of New York and National Weather Service, is constantly looking for better ways to measure it.

At the end of the last decade NYCDEP began using “snow pillows,” essentially scales that weigh snow in remote locations and transmit data wirelessly in near real-time. The technology (first developed by the U.S. Army Corps of Engineers in Alaska) is often integrated into remote sensor stations in rougher terrains out west. The NYCDEP deployed its first snow pillow at the Schoharie Reservoir in 2008, and later near reservoirs in Cannonsville, Pepacton, and Neversink. HarborLAB operates a canoeing and kayaking program at the Neversink for NYC youth groups and public school students to learn about their drinking water sources.

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Inner workings of the NYCDEP’s latest generation snow pillow. Photo by NYCDEP. 

The NYCDEP still uses aerial surveys and good old fashioned field work to measure snowpack, but the agency plans to more than double its constellation of snow pillows to 35 stations in coming years. Another sensor used is the Gmon, which helps researchers estimate snowpack by measuring the absorption of naturally occurring radiation. Future snow data collection might increasingly rely on satellites.

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For more about NYCDEP’s work to measure snowpack, please view this PowerPoint presentation by James H. Porter, PhD, Chief of Water Systems Operations at NYCDEP:

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