Understanding the changing dietary habits of polar bears is the key to seeing how climate change and shrinking polar ice is affecting their lifestyles. And the best way to know what’s happening with their diet? Look at their poop, of course! Linda Gormezano, an ecologist at the American Museum of Natural History in New York City, has trained her dog Quinoa to help her find the best samples left by bears as they cross the frozen Canadian tundra. Gormezano chatted with us about why poop is such a useful scientific specimen and what it’s like to spend months living in a camp in the heart of polar bear country.
What’s ecology and how does it apply to polar bear research?
Ecology is the interaction between animals and the environment. What we’re studying is how polar bears behave on land with respect to available food -- what they eat and where they eat it. What I’m particularly interested in is how they hunt other animals and how the calories they gain from consuming them are going to affect their annual energy budget as their access to ice becomes more limited.
We collect scat and hair samples non-invasively. After consuming food on the ice or on land some bears leave scat. Also some bears rest right along the coast, bedding down in sand and grass where they leave hairs behind, while others head further inland and leave hair in dens.
What, exactly, is an energy budget?
Nobody really knows how often polar bears in western Hudson Bay capture seals, but they get a certain amount of energy from consuming seals they hunt out on the ice and that energy allows them to survive on land for 4-5 months each year. If the ice melting earlier each year causes polar bears to have less time to hunt seal pups in spring, they may be taking in fewer calories over the course of the year.
What we want to know is, now that they’re eating more of certain types of foods on land, what kind of energetic benefits might polar bears be experiencing? Up until now many have thought what they were eating on land wasn’t really helping them at all. To evaluate this, we are examining the energetic costs and benefits of capturing and consuming those foods as well as how often the behavior occurs. Only then can we determine whether these foods could help alleviate nutritional deficits that polar bears may come ashore with.
What do they eat on land?
They’ve always eaten food on land. From historical records, we know they’ve eaten grasses, marine algae, moss, rodents, eggs and birds, even muskoxen. Some of these records date back to the 1800s. Although they’ve always eaten food on land, polar bears are believed to currently be in poorer condition because they have less time to access seals on the ice.
But what we’re finding is they’ve switched their diet. I analyzed 642 polar bear scats collected from 2006 to 2008 and created an inventory of the foods they were eating. We compared our results to a study performed in the late 1960s to see how the frequency of certain foods has changed. We see that they’re eating more of what’s available on the landscape today – especially caribou, snow geese and their eggs.
Populations of caribou and nesting snow geese have both exploded since the 1960s. Also, because the polar bears are coming ashore earlier, they’ve started overlapping the incubation period of the snow geese. When the females are sitting on their nests polar bears can just wander through the colonies, scare off the females and eat their eggs. They occasionally capture the females as well.
The increased availability of these foods coincided with the climate-related changes to the ice, which have only become apparent in the last 30-40 years in the region. If eating these novel foods provides an energetic benefit to bears coming ashore hungry then they may compensate for calories that they lose from not being able to hunt seals. This could increase their chances of surviving on land as the ice-free period expands.
Would it be a surprise if you found out the new eating behavior was beneficial for them? After all, If it wasn’t helping them would they still eat it?
You would think any animal would engage in a behavior that’s going to benefit them otherwise it would be maladaptive. There are questions, however, as to whether a polar bear can energetically benefit from chasing after prey on land. That is, would they gain more calories from consuming an animal than they would spend in the chase to capture it?
We’ve observed polar bears repeatedly chasing and capturing geese when they’re flightless in July and August. We have also found that they use energy-conserving techniques such as ambushing and stalking to hunt birds and caribou, which may allow the some bears to energetically profit, whereas a long chase might not.
Eggs are an important exception to this because very little energy is expended to obtain them. They just need to walk through a nesting colony.
How do you figure out what they’re eating?
We collected roughly 1,500 piles of polar bear scats in summer as the bears were coming ashore. We poke through them and see what remains we can identify.
We collected roughly 1,500 piles of polar bear scats in summer as the bears were coming ashore. We performed morphological analysis. In other words, we poke through them and see what remains we can identify. That involved removing different items like plants, hairs, bones and feathers and identifying them under a microscope or comparing them to a reference collection.
Right now we’re taking it further by doing genetic analysis. For example, we’re using sex markers to match up the diets with the sex of the animal and using barcoding techniques to see if there were certain animals we missed. A lot of times we just saw black substances in the scat and it wasn’t clear what it was. With the barcoding, which we are doing in collaboration with a lab in France, we can see how much of that unknown substance was really whale blubber, seal, or fat or muscle of a land animal. I’m in the process of analyzing those data right now.
Where do you stay when you’re collecting samples?
One thing I didn’t mention is I don’t find the scat, my dog Quinoa finds it. During a good portion of the summer we lived out of a camp, Nestor 2, in Wapusk National Park in Manitoba. It’s pretty remote and only accessible by helicopter. Some of the research is done by foot near the camp, but mostly we get transported down the coast and further inland by helicopter, which is based out of the nearest town, Churchill, Manitoba.
It’s a series of eight buildings, some recently built, others that have been there for many years. There’s a sleeping area, a cooking area, storage, and workspace. It’s right off the shore of the Mast river. We filter water and we’re mostly self-sustaining out there.
It’s a very small community. There are no more than 16 people there at one time. It’s in the middle of polar bear country so we have an electric fence around it and very strict protocols on how to deal with bears.
We have ladders that go up on the buildings so when bears are sighted (we have a rotation of lookouts for bears) everyone gets on top of a building. Even in the middle of the night. The protocols are for the dog also. We made a special ladder for him so he went up on the roof as well. He fell in line.
If a bear is adamant and remains near the fence, we load our shotguns with cracker shells, which are basically noise makers. We have magnum slugs ready to go but we’ve never had to use them. In 46 years of the camp being in existence we’ve never had to destroy a bear.
These protocols are pretty amazing. When they come near the fence we shoot off these cracker shells and hopefully they learn to associate the shock with the loud noise and it scares most of the bears away. There have been exceptions. A cub was able to squeeze through the fence so that the mother and the cub were separated. We eventually got the cub out and no one got hurt.
After the summer work is completed, we close up the camp and take down the fence so bears can access the camp anywhere. Even though it’s locked up during winter, sometimes the bears get curious and try to get in. When opening it up in spring to do a series of projects, we have had damage from bears entering buildings -- very often they’ll just plow through the walls.
They’re attracted to all types of things. They’ve been known to eat SOS pads and cleaners and things that are oil-based. They’re also just curious. Even though there’s no food left and the place is cleaned well, any lingering scents or just curiosity can draw them in.
How many bears live nearby?
There’s a lot of movement of bears around the area. In summer when they’re coming off the ice, they move up and down the coast. Females with cubs and younger bears tend to move further inland and the adult males stay closer to the coast. So we tend to have more family groups and subadults around the camp, wandering around and possibly looking for food.
Although other researchers are tracking movements with GPS collars on some of the females, we prefer to gather this information noninvasively so that the bears don’t experience the stress of being captured.
The number of bears coming ashore and passing through varies depending on the pattern and speed of ice-breakup in Hudson Bay. Some females are attracted to certain denning spots so they may cross the area where the camp is to go to those areas. By collecting passively shed hair from beds and dens we’re hoping to track movement patterns of bears traveling while they are on land and examine the relatedness of bears that hang out together along the coast or den near each other further inland.
Although other researchers are tracking movements with GPS collars on some of the females, we prefer to gather this information noninvasively so that the bears don’t experience the stress of being captured. (You can’t put collars on males because their necks are bigger then their heads and they just fall off.)
How did you train Quinoa to find bear scat?
I got him when he was six months old at a kennel in Rhode Island. His mother was trained for drug detection work and his father for bite work -- attacking and holding people. The people who raised Quinoa wanted to train him for bite work but he wasn’t aggressive enough. They said he was a lover not a fighter. So I thought he’d be perfect for finding scat because he had a strong play drive. He’s a Dutch Shepherd, very agile and high energy. When he was young I got him obsessed with playing ball and hid his toys to teach him to find things. As soon as he found the toy we would play ball.
Then I expanded it to scat. He’s trained on polar bear and coyote scat.
Where did you get the scat to train him?
I got it from zoos around the country, but also local zoos in the Bronx and Queens that housed polar bears. I trained him to do a passive alert when he smelled his target scent – in this case, polar bear scat. That is, he sits down quietly and waits for his reward, which is 5 tosses of a rubber ball or tug of war.
I trained him off of other scents like grizzly, black bear, and red fox to make sure he understood the difference. He knows he only gets the reward when he finds coyote and polar bear.
Does he mostly work in the woods?
In the National Park in Canada where we sample for polar bears the landscape is mostly open tundra. He does work in the woods, too. We work locally finding coyote scat in and around New York City. We were actually in the woods yesterday.
What’s a day like with Quinoa out in the tundra?
We woke up, packed both the collection and dog gear, brought lots of food and water and got ready to fly to study area. If I was working with the dog I often did not carry a shotgun. My PhD advisor at the time, Robert Rockwell, acted as bear warden as well as hair collector and there was usually one other person with a shotgun helping out while I was handling the dog.
We took the helicopter to different spots, landed, and I would put the dog on a 30-foot line to begin sampling. He would weave back and forth along the coast, looking for scat while the others would collect hair or work on other projects that were currently going on. The helicopter would stay in the spot and listen by radio for when to pick us up or fly down the coast to the end of our transect and wait for us (usually half a mile away).
We were always in contact for situations where bears might approach.
What kinds of gear do you bring with you?
For a day of sampling we would bring food for me and the dog, water, reward balls, plastic bags, markers, GPS, and radios to keep in contact with everybody on the ground. We would also bring extra layers in case the temperature drops. In the summer it occasionally goes below freezing, but for the most part it was pretty warm.
If the wind picks up and shifts to the north, it could be 50 degrees and the temperature could drop 20-30 degrees in a matter of minutes. It gets horribly, bitingly cold. Even the dog now has a lot of clothing and booties.
Does he enjoy it?
He’s a working dog. Most Dutch Shepherds just enjoy working and pleasing their owner. He absolutely loves it. When we get close to working, if he sees me pack up the gear, he starts whining and crying and he gets very excited.
How long did you typically stay out in the park?
For the three years that we were collecting scat we would arrive at the end of May and stay until the middle of August. Rather than fly the dog the entire way from NY to Churchill, which was traumatic for him, we drove the dog to Winnipeg, parked our car, and then flew in from there. We usually did the drive in record time. Most normal humans would have taken longer, but we drove around the clock and could do it in three days from New York.
What are you working on now?
There have been sightings of coyotes in Central Park in New York City, as well as different areas of the Bronx, Manhattan and even in Queens. And we know for sure there are plenty of coyotes in Westchester. I’m collecting coyote scat as part of a collaborative project to track how coyotes are moving into and through the city. Are they staying in these parks and how many are there?
The idea is to collect scat and use genetic analysis to confirm that it’s definitely coyote. If the scat is viable enough we can identify individual coyotes and estimate the minimum number that are residing in a specific area.
Remote cameras were first set up and indicated that coyotes have begun to move in. It’s exciting to have the dog signal on scat in areas of New York City where you wouldn’t expect it.
You wouldn’t think of it as a place that’s wild enough to have coyotes, but they are very adaptable and can survive almost anywhere – even NYC parks apparently.
Photos courtesy Linda Gormezano
Not all science is done in a lab by guys in white coats staring into microscopes. Lots of discoveries require brave men and women to put their boots on the ground and get down and dirty in dangerous environments. Every month we’ll profile one of these field scientists, tell you how they do their job, and explain the science behind what they do. If there’s a scientist or field of science you’re dying to hear more about shoot us an email or a tweet: erin at erinbiba dot com, @erinbiba