A Time to Sleep

As autumn moves along and winter approaches, many animals are preparing for their winter sleep so I thought it would be the perfect time to talk about hibernation.

Most of you probably have some idea of what it is from learning about it in school. And I would guess that the example that comes to mind when you think of an animal that hibernates – especially if you live in North America – is a bear. Am I right? I remember that was the example used when I was in school but it turns out that bears are actually not true hibernators.  Surprised?

There are actually different types of hibernation but often science can be thought too complex for the general public (and with good reason sometimes!) so if a term is explained, understood and then used by non-science types, it tends to stick. And for the record, it isn’t wrong – hibernation is the umbrella term for the physiological process - but in recent years more accurate terms have been introduced and are being used more and more.

But let’s start with a definition. Wikipedia defines hibernation as a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. A true hibernator does not wake up during the winter season and due to its lower metabolic rate, lower body temperature and slower breathing, the animal could be mistaken as dead. There is no movement and it takes a long time for the animal to wake up enough to begin moving again. True hibernators are animals like bats, chipmunks, ground squirrels, groundhogs and marmots.

Hibernation is an adaptation to temporary changes in an animal’s environment; in North America it’s associated with winter when an animal’s food source becomes too scarce for it to survive the season. So during the fall, animals that hibernate will eat more food than usual to bulk up so they can live off their extra fat through the winter.

In the case of bears, there are eight different species globally; giant panda, sloth bear, Asiatic black bear, sun bear, spectacled bear, American black bear, brown bear (grizzly) and polar bear. Of these eight species, only four will enter a den during winter months – American black bears, grizzly bears, Asiatic black bears and pregnant female polar bears.

Like a true hibernator, when a bear goes into a den, its heart rate, metabolism and breathing all slow down and they survive the winter months off their fat reserves. The big difference is that bears can and do wake up, and even leave the den for short periods –sometimes looking for food, sometimes stretching their legs. The more specific term for what happens with bears is that they go into a ‘state of torpor’ but because that may sound very complex, when explaining it I say that bears go into ‘a period of dormancy’.  Again, they are inactive and live off their fat reserves – like true hibernators – but can wake up and leave the den. If it’s a pregnant female, she won’t leave the den until the spring because she has to stay with her young.

Polar bears are another case altogether. As they live in the Arctic and need the sea-ice from which to hunt seals, they don’t need to go into a period of dormancy in the winter because their food source is abundant. The exception to this, as I mentioned above, is a pregnant female; she enters a den, has her cub(s) and stays put with her young until the spring.

So, question: ‘hibernation’, ‘torpor’ – why does it matter what word is used? I mean, isn’t it just semantics? There are those who would certainly agree with that. But to me, it’s important to know that there is a difference. Many people run, hike and camp during winter months in bear country and may not consider the fact they could encounter one at that time of the year because they were taught bears hibernate for the entire season. In many parts of British Columbia for example, the weather doesn’t get very cold so bears are likely more active during winter months then you might think. I say the more you know, the better prepared you’ll be!

Animal Adaptations

As someone who focuses on wildlife education both professionally and in my volunteer role, a topic I speak of often is that of animal adaptations. So today that’s what this blog is about, animal adaptations: what are they and how does a species adapt?

One of the questions I get asked quite a lot when the topic of climate change and polar bears comes up is, “Can’t they just adapt to a warmer climate?” Unfortunately, it’s not at all that simple. This is just a basic overview but some content may be a little technical so please bear with me – no pun intended! 

Ok...what are adaptations? In simple terms, an adaptation is a specific characteristic (or set of characteristics) that allows a species to live and reproduce in a particular environment. There are three types of adaptations:

Behavioural:  instinctual or learned behaviours that help a species thrive in its environment.

Physical or structural: parts of a species’ body structure that help it thrive in its environment.

Physiological: parts of a species’ biology (inner workings of the body/organism) that help it thrive in its environment.

Still with me? I hope so.

So, how does a species adapt? Specific adaptations don’t happen overnight, they often take thousands of years to evolve into exactly what each species need to survive and compete successfully within their unique environment.

Because I brought up polar bears above, I’m going to use them as my example here. Polar bears evolved from grizzly bears (somewhere between 250,000 to 400,000 years ago) in order to occupy and thrive in an Arctic environment as the top predator. They went from being an omnivorous, terrestrial animal (grizzly) to a carnivore that is specifically adapted to life on sea-ice, relying on the marine food chain (polar bears eat seals).

Now, if a species’ environment changes can it adapt? Well, rates of change are very important and there will always be different scenarios and variables that prevent a definitive answer. But there is something important to keep in mind when thinking about adaptations – a species is usually considered either a ‘generalist’ or a ‘specialist’, and this can play a key role in their ability to adapt successfully to rapid and/or big changes in their environment.

A generalist is a species whose behavioural, structural and/or physiological adaptations allow it to survive and thrive in various types of environments. A great example of a generalist is a raccoon. These animals can live in many different types of habitats and, as I’m sure you know, even do very well in urban settings. Their adaptations are flexible and general enough that they would likely survive if their environment changed (unless the change was extreme). So don’t hate the raccoon because he was able to adapt to the changes we made!

A specialist on the other hand is a species whose adaptations allow it to survive in a very particular environment and/or with specialized dietary needs. Removing it from or changing that specific environment or food source can make it very challenging and often times impossible for this species to survive.

Back to my polar bear example - you now know they are of course a specialist species and you also know the answer to the question, “Can’t they just adapt to a warmer climate?” They are supremely adapted to their cold, Arctic home. So as climate change melts and alters their sea-ice habitat, it’s not hard to see how increasingly difficult it becomes for these specialists to survive. Remember – adaptations take thousands of years to evolve.

There are almost as many different adaptations as there are animals. As I continue to write about different species of wildlife, I will definitely highlight some really cool and extraordinary examples of their adaptations so you can appreciate just how amazing animals really are! 

The Ice Bear: It’s In My Blood

Fact: I love polar bears. I have since I was a kid. And it’s not just because they are super cool with awesome adaptations to withstand their Arctic habitat, but of course that’s part of it! I had pictures and posters and books about them all over my room growing up. I think I was around 8 years old when I started hearing stories about the three years my dad lived in Churchill (as a boy with his parents & brother) and I was fascinated with the thought of a place, that in my estimation at the time, was the farthest north you could get, was so cold and covered in ice and yet somehow so full of life. Thus began my love affair with the great white bear.

My grandfather was in the military and he was stationed in Churchill from 1954 to 1957. What I heard about most from my grandmother was how cold it was and how the spring and summer seasons were too short for her liking. And while the ice slowly broke up and melted in the spring, you could hear cracks louder than thunder through the whole town. What my dad told me about were his explorations with his brother, looking everywhere for polar bears. He was unfortunate on one hand because he never saw any despite all his time spent outside. On the other hand, he was fortunate not to have ended up nose-to-nose with a bear while exploring the rocky outskirts of town. Many of the rocks are light in colour and it’s easy to mistake them for a slumbering bear; it’s equally as easy to mistake a slumbering bear for a rock and inadvertently end up too close! Still I was surprised to hear that in the ‘polar bear capital of the world’, where tens of thousands of visitors now travel every fall to see these huge carnivores, my dad and uncle never saw even one bear. What I realized later was that while the military was operating in Churchill, the town’s population was around 5,000 people. With all the activity and noisy military vehicles around it makes sense that bears mostly stayed out of town.




Aerial View of Fort Churchill in the 1950s © Lenore N

 



Hudson Bay Shoreline © Lenore N



Years after the military left, the scientists showed up. The southern-most polar bear populations are forced ashore in late spring/early summer when the ice breaks up and they live off their fat reserves until the ice forms again in mid to late fall and they can get back out on the ice to hunt seals. Because there was a town, an infrastructure in place, and above all, polar bears, it was – and still is - the perfect location to study them. To this day, there is more chronological data about Churchill’s polar bears (referred to as the western Hudson Bay sub-population) than any other sub-population in the world. Now of course, scientists are studying polar bears throughout their circumpolar range around the globe and they have become the iconic species for climate change because the Arctic is changing more rapidly than any other ecosystem on the planet.

What I’d like to stress here is that while polar bears are struggling with their changing habitat because of climate change, scientists still have hope that we can save certain sub-populations if we all make a concerted effort to reduce our energy consumption and our dependence on fossil fuels NOW. One organization doing amazing work on polar bear conservation is Polar Bears International (PBI) and I would encourage you to visit their website to find out about their work. In the coming weeks top bear scientists will even be broadcasting live from the tundra in specially equipped vehicles while wild bears roam at the edge of Hudson Bay waiting for the ice to freeze.  Check it out at http://www.polarbearsinternational.org/.

Churchill Wildlife Management Area © Lenore N

Because these bears are still a favourite of mine, this is only the first of my blogs about them. There are way too many stories and cool facts to write about at one time! And as I mentioned in my previous blog, I have had the amazing privilege to observe and work with wild polar bears in Churchill, Manitoba three times in my career. The experiences themselves were very special, but what made them even more special was being able to share my stories and pictures with my dad and grandparents 50 years after they lived there.  

A Passionate Primate

For a while now some friends of mine have been encouraging me to write. They know how deeply I care about wildlife and the natural world and have suggested I share my knowledge, thoughts, stories and experiences.  If you don’t know me personally you will likely be wondering who I am. Let me introduce myself:

My name is Lenore, I live in Toronto and as I mentioned above, I am passionate about wildlife and the environment. My love of animals started at a young age and like many kids I grew up with pets at home. There was also the occasional wild, injured bird in our kitchen while my mom tried to nurse him or her back to health. Mutual of Omaha’s Wild Kingdom was a favourite in our house (I guess that dates me somewhat!) and I was glued to the TV for that half hour. That show was a big reason I fell in love with wildlife, African wildlife in particular and I vowed to one day travel to the Serengeti.

Yet even with such a strong passion for wildlife, I had no idea what I wanted to be ‘when I grew up’, and let’s just say I took the long road to get here! I’ll spare you the gory details but after some bumps and bruises along the way, I was able to turn my passion into a career. I’ve been very fortunate to have worked for several conservation organizations over the past eight years and I’ve been a zoo volunteer educator for almost 13 years. I’ve had some absolutely AWESOME wildlife experiences like travelling to Africa, observing and working with wild polar bears in Churchill, Manitoba, bird banding, releasing Ontario turtle hatchlings into the wild and helping with the rehabilitation of injured wildlife for re-release.

My experiences have taught me many things and I’m excited to share them with you. My hope for this blog is that it inspires those who read it. I hope you will learn things you consider interesting and amazing about animals and that you will come to care as much about them and the natural world as I do. And fingers crossed, that will lead to changes in the way you do things day-to-day. After all, every living thing needs a healthy planet to survive, and that includes us.