How to survive winter

41 degrees Fahrenheit
You’re naked. In a salt marsh. With a giant rock on your back. It’s 41 degrees Fahrenheit. A cold that kills comes tonight. You see someone else. They’re naked. In a salt marsh. With a giant rock on their back. They’re covered in a slimy goop that is sticky and slippery at the same time. They have tentacles on their head. That’s weird. Then you remember, “Oh yeah. I’m a snail.”

As a snail, you are cold-blooded (the scientific term is ectotherm), meaning that you can’t regulate your body temperature internally like those uppity warm-blooded animals (endotherms) like mammals and birds. Your outside temperature is your inside temperature. What happens when the temperature drops below freezing? How do you survive if you are no warmer than an icicle?

38 degrees Fahrenheit
Head south to overwinter in Mexico or the American south like the monarch butterflies, green-darner dragonflies, and not-so-hardy New Englanders? No, you are a slow-footed gastropod and travel only as far as the nearest plant.

36 degrees Fahrenheit
Bury yourself under leaves, moss and the soft soil like the forest and garden snails? There is no moss here. And the leaves are few and the mud is as soft as a cinder block.

Other snails join you at the plant. You all huddle into a cuddle puddle.

34 degrees Fahrenheit
Hibernate like a bear in a cave? Marshes, by their geologic definition of having no rock from which to carve a cave, have no caves. Some snails, if lucky, sneak into crab burrows and stowaway in a muddy hibernaculum. But the holes are few and the snails are many. And a burrow is just a hole and holes are cold.

Your heartbeats slow. 

33 degrees Fahrenheit
Fill your blood with antifreeze like some insects? That’s not a trick you can pull off. But you must do something because cold kills. It’s not the cold itself that kills, it’s the stiletto-sharp ice crystals that form inside your cells. Crystals shred the cell’s membrane and the nucleus and mitochondria spill out like guts from a disemboweled goat. A cell freezing is like stabbing a water balloon with a hundred toothpicks from the inside. Frozen cells die. Freeze enough cells and you die. Winter will kill you.

Or will it?       

32 degrees Fahrenheit
Parts of your body start to freeze.

30 degrees Fahrenheit
The water in your body continues to freeze. But not the water inside your cells, the water outside your cells. The water between the cells. Because of osmosis, this pulls water out of your cells, which makes them saltier. Salty cells, like salted roads, lower the freezing point of water and do not freeze.

22 degrees Fahrenheit
It’s midnight. You heart has nearly stopped. Parts of your body have frozen, but your cells have not. You will survive another winter. But you will still be naked, carrying a big rock, and covered in goopy slime.

It could be worse; you could have a fish living inside your anus.  

 

Saltmarsh periwinkles, Littoraria irrorata, huddled against the stem of needlerush (Juncus romerianus) in Yorktown, Virginia

Snails huddling for warmth. The smaller snails in the foreground are coffee-bean snails (Melampus bidentatus). The larger snails in the background are periwinkles (Littoraria irrorata)

Saltmarsh periwinkles, Littoraria irrorata, huddled against stems of needlerush (Juncus romerianus) in Yorktown, Virginia

A cute cuddle puddle of saltmarsh periwinkles (Littoraria irrorata)

Post-script
Many marine snails use this ‘freeze part of my body’ trick to survive the winter. The snails starring in this essay are the coffee-bean snail, Melampus bidentatus, and the marsh perwinkle, Littoraria irrorata.

Post-post-script
It’s not clear to me why the snails huddle together when it’s cold. I can come up with at least two hypotheses. First, snails huddle together to shelter each other from the wind. Second, they may not be seeking each other, but all seeking a plant to huddle against. Like humans at an airport. You’d like to avoid everyone, but you’re all drawn to the same place and have no choice but to huddle together and try to survive.

The Joker in the Salt Marsh

The Great Marsh, Massachusetts
For C & J.

On a recent sampling trip in the Great Marsh I brought along a new assistant, The Joker. He was done shooting his latest film and needed a break from his general villainy.

The Joker investigates the mud between the stems.

Like some new interns, The Joker was easily distracted. Here he mounts a steed, a horseshoe crab (Limulus polyphemus) molt, and wields a mighty blade of grass.

Come on, Joker! Quit horseshoe-crabbing around and let’s get to work.

The Joker couldn’t avoid villainy entirely as he tried to recruit a horde of coffee-bean snails (Melampus bidentatus) to join his evil gang of gastropods.

He got one recruit. And it totally went to his head. 

As one of the more fashionable villains, he fell in love with a blushing pickleweed (Salicornia europa) that matched his hair and jacket. 

The Joker came across a ribbed mussel (Geukensia demissa)… 

and decided he needed more mussel for his next bank heist. 

 

The Joker learned the different marsh grasses. Here he’s showing a flowering shoot of marsh hay (Spartina patens) that it’s not the only grass in the marsh. 

After he learned his grasses, we finally got to work. Here The Joker is estimating the percent cover of grass in the marsh. Looks like about 100%, don’t you think, Joker?

After a while, I was able to trust him to record data. He was a little slow and a lot messy, but that’s field work sometimes.

As we left the marsh through the woods, The Joker asked for a snack. I said no. 

But we did have a well-deserved swim in the river.

Crawl space menagerie

I found some squatters in my crawl space today. Freeloading vagrants who were living in my house without me knowing. How could they have moved in without me knowing? Usually squatters squat in a house that’s empty but these spineless vandals have no respect for property or privacy.

It’s a good thing most of them were dead.

Snails, centipedes, millipedes, and rolly pollies had moved in to my crawl space when there was a small pool of water. What must have seemed like a lake to them has now dried up leaving their equally water-free bodies to litter the desert of my crawl space. Only one large snail seemed to survive.

The most surprising find was the large claw of a male fiddler crab. I don’t know if I should be excited or nervous that the crabs are trying to move in. Have my experiments with the crabs gone too far? What do the crabs want? They’ve conquered the ocean now the crabs are trying to take over my house? Sure, I’m a scientist, but I was never trained for this. The crabs are a crafty bunch.

The lone surviving snail. It sits upon a Minion hat worn by my three-year-old son (yet another freeloader living in my house).

A camel cricket who stored no water in his hump.

A millipede or a fuzzy cheese doodle.

A centipede or a hair clog.

A gang of rolly pollies and their snail enforcer.

The disembodied claw of a fiddler crab. The body was never found; yet another mystery.

Letter to a Pickerel

Sidney, Maine

Dear Chain Pickerel,

You were only as long as my forearm, but you fought like a hurricane. Your torpedo body whipped and strained against my line. I pulled you into my hand and you calmed. Trying to hold you was like trying to hold an eel. You had a beautiful spoonbill mouth – rounded, not sharp like the garfish or the alligator. The triple barbs of my treble hook were buried in your mouth; I’m sorry. I’m glad that were a young fish with small, backward-facing teeth that did not bury themselves into my hand. I admired your perfect camouflage; from the side and above you look like green water with irregular windowpanes of light. I worried that I had hurt you, but once I removed the hook and slid you into the water, you sulked off into the rocks and disappeared like smoke into fog.

It was nice to meet you.

Sincerely,

~David

P.S. If you enjoyed this letter, you should read John McPhee’s essay, “The Patch”.

A classic print (1896) by S.F. Denton courtesy of The New Yorker magazine.

Who’s in that there hole?

Outer Banks, North Carolina

In this week’s episode of “Who’s in That There Hole?” we travel to a beach on Outer Banks of North Carolina….

While walking on the beach and not paying attention to my three-year-old to make sure he didn’t swim off to Spain, I spotted a quarter-sized hole. The beach had several quarter- to baby-fist-sized holes in the sand, but no obvious occupants. I started digging in the sand, using my hand as a steam shovel. Each scoop of the cool sand got me closer to the treasure I was hunting for. When I was elbow deep in the sand, I found the treasure. Then it pinched me and skimmed across the sand like shuffleboard puck. I chased it into the water and slapped my hand down on it. It was a ghost crab, Ocypode quadrata.

I am the ghost crab. You can’t see me. 

The name Ocypode means ‘fast-footed’ (Ocy=fast, pod=foot, as in podiatrist). And they are fast as a lizard on a hot skillet. These cryptic crabs are found from at least Rhode Island to Brazil and are most active at night. Once, while camping in Perdido Key, Florida, a friend felt something thumping him from underneath his sleeping bag. He lifted up his bag and a large ghost crab angrily shook his claw and ran off into the night.  The ghostly carapaces of these crabs perfectly camouflaged them against the sand so that when they run it looks like a patch of the beach grew legs and ran away.

Ghost crabs live in single burrows above the high-tide line that are 1.5-3 foot deep (so elbow to shoulder deep for me). They are semi-terrestrial, meaning they live on relatively dry land but need to run to the water to wet their gills occasionally. A ghost crab will drown if constantly underwater. So if you find yourself on a beach between Rhode Island and Brazil and see quarter- to baby-fist-sized holes above the high-tide line, it might just be a fast-footed ghost crab.*

*There are other animals that burrow on the beach including rats and fiddler crabs (e.g., Uca pugilator, the sand fiddler). Fiddler crab burrows often occur in colonies with many quarter-sized holes clustered together, not in single burrows far apart from each other like ghost crabs. And fiddlers, unlike the shy ghost crabs, are showboats, the males constantly waving their oversized claws.

Who’s hiding in your mud?

Can you see me?

 

 

 

 

How about now?

 

Now?

I am a juvenile – and adorable and humble – sand fiddler crab, Uca pugilator. I am tiny and an easy snack, so I look like a grain of sand to keep me out of the belly of a bird. 

‘Dagger-faced goons’ murder and eat victim in broad daylight

Williamsburg, Virginia

“A gruesome scene this morning has left a leafy neighborhood in Williamsburg, Virginia, in shock after a newly emerged cicada was murdered, dismembered and eaten in broad daylight.

According to eyewitness accounts, a female Carolina wren (Thryothorus ludovicianus) pulled the victim off the trunk of a tree, threw it on the ground and stabbed it repeatedly with its needle-like bill. Once the victim was dead, another wren, a male, helped the alleged killer ripped the victim to pieces and began eating it. Later, a female cardinal (Cardinalis cardinalis), Virginia’s state bird with eyes set on savagery, joined in to help devour the victim.

“It was brutal, just brutal” said a grasshopper who witnessed the attack. “The poor guy emerged right under the bird feeder. That’s just bad luck. That’s like a gazelle being born in a lion’s den.” After pausing to look over his shoulder, the grasshopper said, “But better him than me.”

We were able to obtain an exclusive interview and confession with the alleged killer, who was taking a dirt bath under a bush. “I was going to eat bird seed from the feeder. Then I saw [the cicada] on the tree. It was the size of my head! So much meat. And delicious. Now I don’t have to spend the rest of the day foraging for insects and seeds. I can focus, instead, on removing mites from my feathers.”

Asked if she had any regrets, she said, “Only that after all my work to kill the cicada, that cardinal bullied her way in. But she only got part of the thorax and the wings. I don’t like the wings anyway. Too stringy.”  

The murder happened in the front yard of a Williamsburg resident who saw it happen outside his window. “I saw the wren pecking the ground, then saw the cicada try to fly away. She grabbed it and flipped it on its back. It was gruesome. I didn’t watch the whole thing because I didn’t want to overcook my eggs. That would have ruined my day.”

The victim was a periodical cicada (Magicicada sp.). These insects remain underground as pale grubs for 13 or 17 years then emerge from the ground as winged-adults to find a mate. They are sometimes called “17-year locusts”, which is a misnomer. Locusts are grasshoppers and cicadas are more closely related to shield bugs and assassin bugs.

The grasshopper who witnessed the murder gave perspective on the victim’s life cycle, “Nothing like waiting 17 years in an underground bunker only to be killed and eaten by dagger-faced goons when you come out.”

 

******
P.S. This makes my 100th post. Thank you for following! Don’t forget to tell your friends and neighbors. But not the creepy neighbors.

 

 

 

Quest of the Tick

I sit at the end of a blade of grass under a blistering 98-degree sun. I wait. The humidity is thick. I wait. The breeze is dead. I wait.

I wait for you.

I wait all day, still as a stone. When I feel your breath, your heat or your footsteps, I throw open my front legs like a spring-loaded trap the snaps open instead of closed when triggered. I wave my legs around eager to grab you. The hooks at the ends of my legs make sure to snag your hair, your clothes, your skin.

I am the tick, and I have waited for you all day.

****

What our eight-legged friend* describes above is the questing behavior of ticks. They sit at the edge of leaves or grass patiently waiting for you or your dog or a deer or a raccoon to walk by. I admire their patience and their clever behavior.

I took the photos below in my backyard after looking for black dots at the ends of grass blades and seed heads. The tick is the Lonestar tick, Amblyomma americanum. Once you know what to look for, it’s amazing, and terrifying, how many ticks you can find riding on the tips of grass blades. Even scarier is the number of ticks you can’t see.

 

*Ticks are arachnids, like spiders and scorpions and mites. They are not insects.

Need a date? Just wave.

Here is a great video put together by the New York Times explaining how female fiddler crabs not only prefer males with larger claws, but also with claws that wave faster. This is based on work by Australian researchers who used robot claws to wave faster or slower. Waving is part of fiddler-crab courtship. So remember, the next time you’re in a bar or the grocery store and you see someone you’d like to court, wave your little claw off!

Blind daffodils and a splat of moss

Snowdrops with raindrops

It rained all day yesterday and the snowdrops are now dappled with raindrops. A splat of moss that has made its home on a slate of stone is without shame and has flashed its naked gametophytes (gam-meat-o-fights), sporophytes (spore-o-fights), and sporangium (spore-anj-e-um) for anyone to see. Don’t worry if you don’t understand the sex life of the mosses. I don’t either. So long as the mosses have it figured out, we shouldn’t worry. Throughout the neighborhood, the daffodils have put up their green swords ready to charge into spring. But they charge blindly because they yet to reveal their crowned heads. But I can’t criticize, when I blindly stuck my head out this morning I had to retreat and put on a knit hat. Spring may be coming, but it is winter that is here. 

A splat of moss on a stone of slate

Blind daffodils

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