Thursday, November 7, 2013

February: Ice and Sex (for otters and beavers)

One cold sunny day, February 25, 2003, I tracked otters for 4 miles

and didn't get home until the dark of night when the predicted low was minus 15 F. One stumble on my snowshoes and I might have been in a predicament. Indeed, in the dark I saw a dead deer that I guessed, wrongly, had stumbled as coyotes chased it.

That whole month I had been observing how my fellow mammals survived the winter, but they did it by going under the ice.

Of course, I couldn't fit.

Last month, October 2013, I posted my journals from February 2003 on my blog Bob's Winter Journal. Not surprisingly, after ten more years of watching otters and beavers, I view their lives differently now.

As children we are taught that animals that don't go south hibernate in the winter. The bear is the example that becomes the norm. Groundhog's Day is the annual refresher course. Thus the hole in the snow and ice is an invitation to warming sleep, which is the key to each animal's survival,  such a good story to tell children. By 2003 after almost 10 years of watching animals in the swamps, I saw through that. Animals could be quite active in the winter, and I decided it was because they were hungry; despite all their preparations for winter, they could get desperately hungry.

Now I am beginning to see through that. I forgot the imperative to procreate.

The obsession of adult animals in February is not food for its belly, but sex, the survival of the species in a cold and indifferent universe.

Not that I saw any sex in any holes, except out in the river where, thanks to a current picking up in the American Narrows of the St. Lawrence River, the water seldom freezes outside my house.

and the ducks thrive in holes in the ice where there is open water. I saw the ducks, mergansers, goldeneyes, scaup and mallards, every day in the river outside my door. In the harshest winter conditions they divided their time between foraging and courting.

Although I devoted many days to studying them, I seldom saw mammals out in the swamps. In February 2003 I saw beavers twice, the first time in the Second Swamp Pond on Groundhog's Day and looking for its shadow seemed to be the last thing on its mind.

The snow was almost deep enough

to keep it from getting back to its hole in the ice.

On the 18th I saw two beavers out in Meander Pond, coming out of a hole in the ice.

There was no doubt in my mind, ten years ago when I saw these beavers, that the beavers were hungry. Now I have my doubts less because of new evidence but simply from sitting by beaver ponds too long and thinking. 

The generally accepted description of beaver behavior in the winter doesn't stray too far from the bear paradigm. Beavers can react to the cold by retreating to their lodge and depressing their vital signs into a near state of torpor thus obviating their need for food. They also amass a cache of branches near the lodge that they can access underwater and strip off bark to eat as needed.

By accepting that as normal behavior, I had to consider their coming out of holes in the ice and cutting trees as an admission of error on their part. As if to say they were so hungry torpor was impossible, or, warm temperatures fooled them into thinking it was spring. And they were so improvident they forgot to cache enough food for the winter.  

However, in the fall and spring, I frequently saw a whole family of beavers foraging, but in February I usually saw one beaver. Twice families I was watching had to relocate their lodge in the middle of the winter and in those cases I did see family foraging in February.

But when the family stayed put in one lodge all winter, I saw one beaver, sometimes two, foraging. 

Of course the forager often took logs and branches into the hole in the pond ice.

If only one person shops, it doesn't mean that the rest of the family isn't hungry.

Otters also use the holes in the beaver ponds. I see their slides going into them as I did throughout February 2003. That's what kept me going back to the swamps even as the temperature hovered near 0F. Beavers don't come out of their holes if it is too cold. Otters don't mind when its below zero. I wanted to see what the family of otters I had often seen in the fall

was up to in the winter when they came out of their dens under the ice of the beaver ponds.

I saw their scats accumulate outside the holes. 

It was black and dripping in great gobs just below a hole beside a beaver dam.

In February there is no food for otters outside the holes, though they often bring what they caught in the water under the ice up on the ice to eat.

Once in a pond with enough fish to eat, otters can spend five weeks there without coming out. More commonly, otters stay under the ice for several days at a time. They do move from pond to pond throughout the winter and at first I assumed that was dictated by running out of things to eat.

Otters commonly make holes through beaver dams that drain most of the pond water making fishing in the remaining pools of water easier.

But then I noticed, especially in February 2003, that they often came out of a hole in the pond, slid and scampered on the pond surface and then went back into the same hole. Exercise and fresh air?


There are three truths about winter that animals understand: travel is easy, food is scarce and time is short. That is, the time to prepare new born animals for the next winter is short. Sex has to be their obsession. Indeed in the case of the otter, the idea of nestling down for a long winter's nap is ridiculous. I knew that in 2003. The mother otter has to abandon her pups, mate with a male, and find a natal den, all between January and April. That's a natal den for her new pups who were conceived 10 months ago and survived in her body thanks to delayed implantation of the eggs.

In 2003, I understood that about otters. So I wasn't surprised tracking them for two miles in the hard snow. I must admit it took me a while to understand how easy travel is in the winter. Indeed, there is no better time to travel in the woods and over ponds and rivers. I eventually grasped a scary truth about below zero Fahrenheit. Not only is it easy going anywhere across the frozen snow, but walking on and on is the best way to keep warm.

Beavers are monogamous but so that their new born kits have enough time to learn the ropes in order to survive their first winter, the beaver mother best give birth to her new litter by June. With a gestation period of up to 120 days, she needs to conceive in January and February. So lapsing into a torpor comes at a price -- extinction.

There are two views of monogamy. It's on autopilot or it's a constant struggle; it being sex.

In the animal kingdom, hormones get it done, but lower animals are not exempt from constraints. In the beavers' case, the constraint is the almost constant presence of the family all crowded in the lodge. Not only do parents sleep all winter in a lodge with their kits, but older offspring can return to the family to "help out."

Scientific observation (not by me, but by scientists) has established that adult beavers lose weight over the winter. But I think collecting fresh bark in the winter has two purposes: to keep the sheen in the fur of the parents and to distract the young.

I used to think having otters drain most of the water out of their pond must make beavers hopping mad, but it doesn't. With the water out of the pond it is easy to get around under the ice, to get around, to get away, to be off alone, to separate from their young.

Of course, this is reasoning by analogy, with a dash of deduction. Why should stolid beavers behave at all like quicksilver otters?

I've shared photos of the wild tracks of the otters. Now study the straight and narrow of the beaver:

Well, not so straight, but to the point, right toward the food. That photo gives too modest a few of the beavers' appetite. Here's the view of their lumbering, looking in another direction on another February day when the snow was not so deep.

Why am I wasting your time by suggesting the beavers aren't starving? As I walked down the pond toward the dam, I saw two adult beavers below the dam, not courting, but collecting logs. Unless that's the way beavers court. 

At the end of this blogs, I'll share the links to my February 2003 journals on my winter blog. They will show that I was thoroughly confused by the otters and pretty confident that the most active beavers simply didn't prepare for winter. They holed up in a small, shallow pond and planned to cut trees all winter.

Unfortunately, I haven't put my September 2002 journals on the line that describe two kits, if not three, ranging around this small shallow pond supervised by nothing bigger than a yearling beaver.

Nor have I put the November 2002 journals on-line describing several trails in the first snow going to downed trees all around the pond.

If the three or four younger beavers in the lodge were hungry in February they'd be out eager to eat just as they were in September and November. I don't think it has anything to do with fear of predators. They are even hungrier in late March when all the beavers will be out foraging again. The point is that young beavers are not sexually active. Conversely, I have kept an eye on ponds in which only one adult beaver lives. That single beaver never comes out in the winter.

But why would a monogamous pair perpetrate such heroics in the name of sex?  

The amount of winter lumbering at Meander Pond was the most I had ever seen. But the beavers at the Second Swamp were no slouches.

The usual explanation for such seemingly unproductive patterns of gnawing is that beavers are simply wearing down their teeth which are always growing.

Late in the month the East Trail Pond beavers became active and dragged branches down a considerable slope to jam in their hole in the ice.

That seemed to be a clear case of assuaging hunger but as I wrote in my journal as I observed this: If these were starving beavers one might expect an orgy of eating until the next deep freeze, but these beavers couldn't be that hungry -- not even a sound from them under the ice or in the lodge.

That I observed beavers during the day doesn't make a difference as the temperature every night in February ranged from below zero to 10F, which means that if they do anything they do it during the warmer daylight hours. We had few brief thaws that February.

Only at the Lost Swamp Pond did the beavers not break out from under the ice in February. I grew worried and late in the month stood by their lodge and saw vent holes and heard mewing inside.

As the photo above suggests, this was the biggest beaver pond I watched that winter.

Evaluating this evidence scientifically one looks for the simplest sufficient explanation and that would be that the beavers were simply hungry and that only adult beavers braved the winter conditions. Younger beavers have no experienced foraging in the tricky conditions of winter, i.e. don't let the holes into the pond freeze over. That otter behavior, abandonment of pups and search for mates, was dictated by sexual needs has no bearing on monogamous beavers.

The otter analogy is important to me because it shows I am not anthropomorphizing when I am suggest beaver behavior transcends a  sufficient scientific explanation. Yet it makes scientific sense to me that animals who face hard winters have evolved so that sexual needs distract them from their hunger. So the provident beavers who, adept at metabolism control, could survive the winter without lumbering in the ice and snow and who has mated for life shows its hot love by cutting down and sharing fresh cold bark.

At the root of my argument is my 20 years of watching beavers. As monogamous pairs go, beavers seem prickly to me. Otters are far more affectionate, at least as far as the mother's concern for her pups. Here's the video from which I lifted that still of 6 otters on a beaver lodge. 

That large otter may have been the father, but otter fathers are rolling stones and I have seldom seem them interact with their "family." 

Beavers do mutually groom each other, which always makes a good photo, like these two beavers in the East Trail Pond in November 2002.

But in my experience they mutually avoid each other far more often and that is hard to capture in a photo and will have to be the subject of a future blog. So each winter mating can't be mechanical. Beavers are too use to shoving any other beaver away. Mating has to be magical, half stripped logs of tasty red oaks to reignite the flame.

The winter of 2003 didn't quit. And on March 15 as my 16 year old son and I stood on the icy snow of the East Trail Pond, we saw a beaver dragging a large branch down the hill north of the pond toward the hole in the ice that had been in business since mid February. After a hard winter under the ice one might expect any animal to be so weak you could knock it over with a feather. The beaver that came down to stare at us looked in top condition.

My son who held the camcorder almost ran when the beaver made a move toward him.

Mating over, the beaver was now about to whip all the sleepy young ones into shape. 

As promised, here are links to my February 2003 journals.

First week of February 2003 

Second week February 2003 

End of February 2003 

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