Hibernaculum (The Snake Den)

A what?

Hi-ber-na-cu-lum.

Two Garter Snakes and a skin of the third one on their departure from a winter's den. Snakes have no hearing but they sense vibrations.

A hibernaculum (plural hibernacula)  
The word originates in Latin, meaning "a tent for winter quarters"; a place in which a creature seeks refuge, such as a bear using a cave to overwinter.Check it out at Wikipedia

It is somewhat like my house in the winter - I crawl in, fire the woodstove and refuse to go out. 
I know, shame on me! 
But, when the snow piles high and the house is warm and the bed is cozy ... well, that is my hibernaculum from January until the late, late March. 

Could I go skiing. Or snowshoeing. Or snowmobiling .... ???

Well, I am sorry, I pride myself on being well synchronized with Nature! 
And ... how many animals bears or bats or reptiles have you seen skiing, I ask!
None!
They, like I, are wisely tucked in their hibernacula - the underground burrows, crevices in rocky outcrops, caves and other cavities placed well below the frost line where the temperatures hover in an acceptable range. It is all about survival until the Spring returns! 
You see? 


For years I only read about such arrangements well known in the animal world. 
But about 3 years ago, I finally discovered "my own" snake hibernacula, and yes, it is the plural!
There were 2 sites and both belonged to the Garter Snakes of Southern British Columbia.(Spp. Thamnopsis)

Please do not kill garter snakes in your garden.
They are not poisonous and they are extremely useful to all.

For those who want to read more about these, often misunderstood reptiles of British Columbia, there is a wonderful website:
http://www.bcreptiles.ca

If you check it out, you will discover that there are several species of Garter Snakes and that there identification is somewhat confusing. But they all belong to the same family.

The very first snake den I found was in the low-lands of  Creston Valley, BC. 
It was the end of April, the time of awakening in the swamps by Creston Wildlife Centre.

The holes in the bank are entrances into the den.

I was photographing cliff swallows nesting under an old bridge that spans the river. The bank was very steep and dry and extremely hard to negotiate.
As I was sliding down on my butt, backpack with the camera on my back and tripod in my hand (There MUST be a better way to do this!), something moved in the clay that was crumbling underneath my clumsy feet. It was hard to spot at first because it was so well camouflaged against the dirt and the dry grasses of the bank. A garter snake!
It swiftly slithered towards one of the holes that dotted the bank and disappeared into the darkness of a tunnel leading somewhere deep and underneath the highway above.

It did not occur to me at once (duh) that the place could actually harbor more than one snake....many, many more than one!




Down I continued, finding the swallows and dreading the thought of clawing my way back up. 

The snakes, meanwhile, decided that all was clear and slithered back out to bask and warm up on the bank. 
Did I mention the it was the South-facing side and that it was a warm and sunny afternoon? 

Contemplating the best approach to my ascent I stood motionless eyeing the steep slope in front of my very face.
And then I finally saw it. I was staring straight at a pretty large motionless snake. And not far from it,  one, two ... smaller snakes could be seen. And another! They seemed to be drawn toward the large one. The female. 

Snakes are not slimy. Their skin is smooth and dry

As I tried to set up my equipment they took off into the safety of their den. But after I scrambled up the bank and all was quiet they cautiously re-appeared.

A year later, in early May, I went back to the place. 
And yes! The snakes were there. Which means that they used their denning site, their hibernaculum, again (and again as they have done many times before).

This time, some were already shedding their skins.

Like most reptiles snakes molt several times per season. They shed their skins all at once rather than scraping off just  small pieces. 

When a snake is about to molt it looses interest in food. Its eyes cloud over, indicating that new tissue is forming underneath the old. Until its eyes clear, several days before molt, the snake stays in hiding. Then it begins to move about, rubbing its jaws and snout against rough surfaces. Normally the skin on the head pulls away first. 
Then the snake winds its way through rock crevices or brush, causing the skin to be pulled away inside-out.

Den Site # 2:

One month later, in early June, I happen to kayak a small mountain lake in Selkirk mountains some hundred km from the Creston Lowlands.
Penstemon and wild Bog Orchids just started bloom and the rocky outcrops by the far side of the lake were covered in bright colours. 
Of course I got out of the kayak to photograph the beauty of it all.
But the wind was blowing hard and it took some patience  to snap a photo. 

Oh, how I cursed that wind!


I shouldn't have!

The wind made me stand still, very still.

And in a while, there was another sort of movement.

Slow, cautious, inquiring.

A beautiful garter snake came out of the depths of the rocky outcrop.
It was trying to figure me out for a long while. But then I shifted my weight and the snake took off.

So sorry to see it go I was going to pack up. But then - a few meters away I noticed another one.
How could that be? It is already June and the snakes are out of their dens.

But this is not a lowland - we are over 1000 meters up!

Soon after they started to come out in numbers!


Another hibernaculum discovered!

Some have already shed their old skins, some, somewhat slow and docile showed the clouded eyes as the new tissues formed under the old skin. And so we spent some time together, the snakes and I, not disturbing each other, 

I, taking the photos, they, changing their skins and preparing for their mating season. 

The large females will give birth to their live offspring and everyone will disperse. They will travel wide and far to make a living catching fish and amphibians and small creatures like bugs and mice. Or chipmunks. Find some bird eggs or their young. 

That's what the snakes do.

They will hide from owls and hawks, the foxes and coyotes, from humans and their pets and cars. 

And when the weather turns cold, the surviving ones will swim and slither back to their rocky outcrop on the lake, by the bridge or under the greenhouse in someone's garden, to hibernate. 

These two will shed their skins soon. Have a look at their eyes, they are cloudy.

 I assume that the smaller one is a male, the large one a female.