Questionable claim: ‘Reindeer adapt to climate change by eating seaweed’

From the NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY and the “blaming climate change for anything odd is now fair game” department.

Stable isotope studies of reindeer poop reveals survival secret

Reindeer adapt to climate change by eating seaweed

The bodies of Svalbard reindeer are extremely well adapted to their arctic home at 79 degrees N latitude. As the northernmost reindeer population on the planet, they are thick and round, which makes it easier for them to tolerate the cold.

They’re shorter, smaller and much more sedentary than their cousins on mainland Europe and North America, too. All these characteristics make them much more physiologically efficient, enabling them to survive long cold nights on the sparse vegetation on the island archipelago.

Given Svalbard’s extreme winters, however, you might guess that global warming might make it easier for the roughly 20000 reindeer that live there to thrive. A new study from a team of researchers led by the Norwegian University of Science and Technology shows that this isn’t necessarily so.

Winter climate change now makes for tougher conditions for these reindeer — enough to force them to eat seaweed, which is not their normal fodder, the researchers report in an article in Ecosphere. But this adaptive behaviour may be one key to their long-term survival.

Desperate measures during icy winters

Biologist Brage Bremset Hansen, from the Norwegian University of Science and Technology’s Centre for Biodiversity Dynamics, and his colleagues have been studying reindeer on Svalbard for decades — long enough to begin to notice an increasing number of warm winters where rain would fall on the snowpack, creating an impenetrable layer of ice on the ground.

The layer of ice makes it difficult, if not impossible, for reindeer to get at the small plants and grasses they graze on during the winter. So what do the reindeer do? They start eating seaweed, Hansen and his colleagues from the Norwegian Polar Institute, the University of Alaska Anchorage, the University of Aarhus in Denmark and UNIS, the University Centre in Svalbard found.

Yes, that reindeer is eating seaweed. But more than visible proof, researchers have studied stable isotopes in reindeer poop, which confirms that reindeer do eat seaweed.
CREDIT Photo: Brage B. Hansen/NTNU

The researchers started their study because of one particularly bad winter when the tundra was covered with ice. Then, they observed that roughly one-third of all the reindeer they saw were feeding at the shore, rather than trying to paw through the ice to reach tundra grasses.

Hansen said he and his colleagues assumed the reindeer were feeding on seaweed, “but of course you need more hard-core evidence to show that this was linked to poor conditions, not just coincidence.”

Poop isotopes help distinguish between diets

So they devised a way to figure out if indeed reindeer were eating seaweed, and why.

This involved — and there is no polite way to say it — collecting and testing their poop. It turns out that researchers can distinguish between different kinds of food animals eat by testing their hair or their scat for isotopes.

In this case, the researchers collected reindeer poop from animals that were in habitats near the shore as well as from animals that lived in areas far from the shore. They then looked at stable isotope ratios of carbon, nitrogen and sulphur, all of which will have values that are detectably different in scat from reindeer that eat seaweed compared to scat from reindeer with a more traditional diet of terrestrial plants.

The researchers also had nine years of data for ground ice thickness, which they called basal ice. They combined this with GPS collar data, and location data from a total of 2199 reindeer observations during those years. They were then able to calculate where the reindeer were with respect to the coastline, and to see if more reindeer went to the coast to feed in years when the ground ice was thicker.

Bad winters make for a seaweed diet

It turns out that, yes, when thick ice covered their preferred food, reindeer will eat seaweed, the researchers found.

But they don’t exclusively feed on seaweed, the stable isotope and GPS collar data suggested, and instead eat as a supplementary source of nutrition.

“It seems they can’t sustain themselves on seaweed. They do move back and forth between the shore and the few ice-free vegetation patches every day, so it is obvious that they have to combine it with normal food, whatever they can find,” Hansen said, adding that the researchers had not done any physiological tests to see how much nutrition the reindeer actually get from seaweed.

Eating seaweed may provide a few extra calories to the reindeer, but it came at a cost: seaweed eaters had a lot of diarrhea, probably from the salt, Hansen said.

“When conditions are harsh, during bad winters, the reindeer do tend to be more often at the beach, and yes, they eat seaweed, confirming our hypothesis,” Hansen said. Although eating seaweed isn’t ideal, he said, it does show the animals are able to adapt, which is the good news.

“The bigger picture is that, although we sometimes observe that populations crash during extremely icy winters, the reindeer are surprisingly adaptive,” he said. “They have different solutions for new problems like rapid climate change, they have a variety of strategies, and most are able survive surprisingly hard conditions.”


Commentary by Anthony:

The idea that this is a new phenomena that is a response to climate change, seems on the face of it, an absurd claim. Basically the researchers are saying that before “climate change” became the universal boogeyman on which anything out of the ordinary can be pinned on, that reindeer never had to face harsh winters before.

I asked zoologist Dr. Susan Crockford about it, and she had this to say:

I do know that reindeer, like most ungulates, are very attracted to salt. i.e., ‘salt licks’ (the ocean seaweed is salty). I can’t imagine it’s a new phenomenon, just a newly-discovered one.

It has been suggested that the salt in the urine deposited by Lapp herders has been one of the things that has kept semi-domesticated reindeer from just wandering off, since they are not truly ‘tamed’ or controlled by fencing, etc.

Also, sheep in northern Scotland are known to eat kelp when there is no other forage.

I found the reference to the Kelp claim about sheep in Wikipedia of all places: North Ronaldsay sheep

Studies have shown that, due to preference and availability, the sheep eat mainly brown kelps. This discovery led to suggestions that kelp may be of use as an alternative food source for other livestock.[38]

The grazing habits of the sheep have also adapted to their unusual diet: instead of grazing during the day and ruminating (digesting) at night as other sheep generally do, the North Ronaldsays graze as the tide uncovers the shore (twice in 24 hours), ruminating at high water.[39] Feeding begins around 3.5 hours after high tide as the areas of kelp and seaweed are exposed. Four hours later, which is just after the low tide, feeding ends, allowing rumination to begin. This cycle reduces the chance of the sheep becoming stranded at sea by the incoming tide.[40]

Unusually for sheep, the North Ronaldsay fattens in winter when storms throw larger amounts of kelp and seaweed onto the shore and food is abundant.[41]

Seems to [me] that the reindeer “discovery” is much ado about nothing, and certainly nothing to do with “climate change”.

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April 24, 2019 2:26 pm

I’m pretty sure reindeer are well adapted to eating any plant material that they can get their little hooves on.

Reply to  MarkW
April 25, 2019 3:55 am

The researchers started their study because of one particularly bad winter when the tundra was covered with ice.

It turns out that, yes, when thick ice covered their preferred food, reindeer will eat seaweed, the researchers found.

“When conditions are harsh, during bad winters, the reindeer do tend to be more often at the beach, and yes, they eat seaweed, confirming our hypothesis,” Hansen said.

I’m confused.

Iffen it’s a BAD, BAD winter and the tundra is covered with thick ice, is not the coastal waters near shore also covered with thick ice, ……. and iffen so, …… where did the seaweed come from?

Reply to  Samuel C Cogar
April 25, 2019 7:16 am

I would think that the salt in the water being sprayed up from the ocean would cause less ice to form near the ocean.

Reply to  Samuel C Cogar
April 25, 2019 7:21 am

Also since the ocean cools more slowly than the land, ice will form later at the beach compared to inland.

Reply to  Samuel C Cogar
April 25, 2019 9:24 am

No, a “bad” winter for arctic reindeer is when there is a longish mild period followed by renewed cold which results in vegetation being covered by an ice crust.

This happens occasionally just about everywhere, but is more common on Spitzbergen where winters are long but fairly mild and there is open water to the west, so mild periods with temperaturea above freezing are fairly common.

Reply to  Samuel C Cogar
April 25, 2019 1:01 pm

Now I know why and am no longer confused ……………..

The North Atlantic Current moderates Svalbard’s temperatures, particularly during winter, giving it up to 20 °C (36 °F) higher winter temperature than similar latitudes in continental Russia and Canada. This keeps the surrounding waters open and navigable most of the year. Svalbard is located in between two ocean currents – the warm Atlantic West Spitsbergen Current and the cold Arctic East Spitsbergen Current.[3]

Reply to  MarkW
April 25, 2019 8:19 am

I was once highly entertained by the sight of a young, female reindeer busily deconstruction someones rose bushes. I doubt that roses are a normal part of their diet, but she seemed perfectly happy with what was on offer.
I live in north Norway.

Reply to  MarieC
April 25, 2019 8:21 am

That should read deconstructing, not deconstruction. Don’t you just love autocorrect?

nw sage
Reply to  MarieC
April 25, 2019 7:43 pm

I suspect that many ruminants really like roses. I know the deer around us REALLY like my wife’s rose bushes! (but a few bars of her best smelling bath soap hung on the branches tends to discourage the munchies)

April 24, 2019 2:29 pm

..and yet…seaweed is promoted as a super food

Reply to  Latitude
April 24, 2019 2:59 pm

Seaweeds are plants that grows in the ocean. The oceans have virtually every mineral on the planet in solution, perfectly mixed. So seaweed contains all those minerals and in a form that is perfectly suited for use by animals that eat it. I’m sure it’s very good for reindeer and the reindeer instinctively know how good it is. But I imagine they wouldn’t want to survive solely on seaweed.

Reply to  a
April 25, 2019 4:56 am

I watched a documentary (in the 80’s, I think) about reindeer. Yes, they do indeed eat seaweed, but they need a certain amount of ordinary forage to balance it out. This is by no means a new discovery.

April 24, 2019 2:30 pm

When I lived in the Cotswolds some twenty odd years ago there was a butcher in Cirencester that in season sold North Ronaldsay lamb which was renowned for eating seaweed cast up on the beaches by winter storms.
It was a small beast with dark meat and a gamey taste.
Quite delicious!

Reply to  roger
April 24, 2019 3:09 pm

I was wondering how the kelp affected the flavor of the Ronaldsay lamb, roger, or if it seemed to have any effect at all.

Thanks for the boots on the ground fork on the plate report.

April 24, 2019 2:36 pm

“Seems to (me)? that the reindeer “discovery” is much ado about nothing, and certainly nothing to do with “climate change”.

Great post..

April 24, 2019 2:36 pm

Ungulates have used any sort of ‘salt’ lick since before time…….head up any ‘pass’ in the mountains and you will see them licking the ‘piss’ of the road all the time.
Nothing new here…move along.

April 24, 2019 2:40 pm

As a point of interest regarding the North Ronaldsay sheep, the islanders keep them on the foreshore where they graze the kelp, this is not a “choice” between kelp and grass by the animals. The stone built wall around the island which excludes the sheep is a Grade 1 listed structure and much effort goes into the annual summer repairs.

April 24, 2019 3:00 pm

What do the herders say?

This looks like a case of: city “scientists” arrive somewhere they know nothing about and decide that a common event is new, because they did not know about it before.

Maggy Wassilieff
April 24, 2019 3:30 pm

I’ve seen cattle feeding on seaweed on the rocky coast on the Chatham Islands (NZ).
Here’s a clip of pregnant cows feeding on Bull kelp, King Island (Tasmania)

We even feed dried seaweed to our cattle.

ray boorman
April 24, 2019 3:34 pm

Anthony, you old cynic.
Surely you don’t believe that reindeer, in their millions of years of existence, might have survived a few winters when food was scarce by being adaptable to conditions that changed literally overnight?

Bruce of Newcastle
April 24, 2019 3:38 pm

Wild creatures will eat anything edible. I have rainbow lorikeets that come to my yard – they’re normally nectar eaters but some have gained a taste for meat. They will chase the Australian magpies away from their meal and steal it, despite being a third the size of the magpie.

Reply to  Bruce of Newcastle
April 25, 2019 7:26 pm

Bullying magpies? The lorikeets have more guts than most Australians.

comment image

April 24, 2019 4:01 pm

‘They’re shorter, smaller and much more sedentary than their cousins on mainland Europe and North America, too. All these characteristics make them much more physiologically efficient, enabling them to survive long cold nights on the sparse vegetation on the island archipelago.’

Uh, no. Biology 101. The ratio of surface area drops rapidly as animals increase in size.

Svalbard reindeer should be LARGER than their cousins, if an adaptation to colder weather. Saskatchewan whitetail deer are 3 times the size of Texas whitetails.

Steve Reddish
Reply to  Gamecock
April 24, 2019 10:26 pm

Animals in cold climates get larger if food is abundant. It seems the critical issue is “sparse vegetation on the island archipelago.” Biology 101: island dwelling herbivores get smaller due to limited grazing range.

That Svalvard reindeer are smaller than other reindeer is evidence they have had a limited food supply for a very long time. I imagine their situation was worse during the LIA.

I would allow for ignorance on the part of these researchers, but this is Norway! They should know basic facts about reindeer. I’m left with only one conclusion: they have jumped on to the Climate Change bandwagon.


Joel O’Bryan
Reply to  Steve Reddish
April 25, 2019 2:22 am

Not bandwagon but the Gravy train.

Steve Reddish
Reply to  Joel O’Bryan
April 25, 2019 10:22 pm

The Climate Change bandwagon is hitched to the Gravy Train.


Reply to  Gamecock
April 24, 2019 11:49 pm

It depends on food supply: better to be small and fat than big and thin in a cold environment. Consider the Shetland pony as a good example.

April 24, 2019 4:02 pm

In the 20s and 30s the local dairy (in S.E. Alaska) used seaweed to feed the cows when the supply of hay was short. One old timer commented that it sure made the milk taste funny.

One isolated family was short on rations one winter and the kid was found eating seaweed on the beach by a trapper friend on mine. He took pity on the kid, and they were still great friends years later. They both have since died.

Odd how our modern society seems to have lost a lot of the survival knowledge. Eating seaweed is an adaptation to survive many things, not just some minor adjustment in climate.

April 24, 2019 4:05 pm

Svalbard reindeer are a great deal smarter than the supporters of Alarmist Global Warming/Climate Change and know what is good for them. They know that kelp and seaweed are superfoods.

April 24, 2019 4:11 pm

Reindeer poop, unicorn poop, the poop that passes for climate science; it all just a smelly mess which keeps people from getting to close to the truth.

April 24, 2019 4:43 pm

One of the theories on how humans came to the Americas was by sailing down the west coast eat kelp (seaweed) as they went.

April 24, 2019 5:08 pm

OR, on the other hand maybe the reindeer just wanted the salt.

April 24, 2019 5:20 pm

A good rule of thumb is to not trust anyone named Hansen on matters of science.

Reply to  philincalifornia
April 25, 2019 4:03 am

I second that.

John Robertson
April 24, 2019 5:49 pm

Unprecedented…..all over again.
Maybe these people should be hiring English Majors in place of themselves.
What is next?
We will actually measure something and discover something new?
On the brightside,we have something new to add to the List.
That list of things caused by Global Warming/Climate Change..Is there anything it can’t do?

April 24, 2019 6:29 pm

Now there’s a CV enhancer.

– Analyzed Reindeer Poop

It’s not just anybody who can put that in their CV.

John Thorogood
April 24, 2019 10:05 pm

Morning Anthony
Squarely in the middle of the “no schist Sherlock category. Maybe even worth a “F***-off Watson” response.
And a very good ANZAC day to all our antipodean allies.

April 24, 2019 10:40 pm

Wake me when they start eating humans as supplementary food.

April 25, 2019 12:07 am

One of the things that will show the tide will really have turned sticking ‘climate change ‘ into research that has nothing to do with it , is not seen as a good approach to get the grants in and show the authors ‘progressive ‘ credentials as seen in this paper.

michael hart
April 25, 2019 12:54 am

It doesn’t surprise me if they already ate seaweeed. I recall once reading that Scottish deer, unlike sheep and tiggers, will actually eat thistles, thereby increasing the quality of pastureland (unles one is a thistle aficionadom which is certainly possible in Scotland).

Reply to  michael hart
April 25, 2019 4:45 am

Not as funny as you think, in the early history of Tasmania a lunatic Scotsman rode on the back of a stagecoach from Devonport to Hobart scattering Thistle seeds as he went.

michael hart
Reply to  Ve2
April 25, 2019 12:24 pm

…and the thistle has been Scotland’s national emblem for more than 500 years…

Martin Howard Keith Brumby
April 25, 2019 2:26 am

You might want to check out what reindeer get up to if they find fly agaric fungi….

April 25, 2019 3:34 am

sheep goats cattle and horse all enjoy seaweed snackies and its good for them, bullkelp meal is over 200$au a bag sold as stock food additive here in aus. the fools in power banned people using seaweed collected from beaches years ago. yet commercial suppliers get the nod?
some seaweeds are now proven to kill or regress cancers.
almost all Sth Aus beaches were loaded with seaweed in huge rafts when i was young, 15yrs later it was hard to find any, the reason??? sewage effluent pumped into the gulf killed the seagrasses very efficiently.
but getting anyone to admit that has taken years and even now its easier to blame warming or farmers runoff than admit the truth

Philip Finck
April 25, 2019 6:02 am

The story is hog wash. Growing up on an offshore island in Nova Scotia I can assure you that deer eating seaweed, and in particular kelp, isn’t anything special. In fact it is the norm. During a fine sunny day in the summer a typical walk around Flat Island, about an hour jaunt, will reveal about 20 white tail deer. The vast majority will look up at you from the beach with a long streamer of kelp in their mouth. Again. this is summer with lots of available on land forage. It isn’t winter with a lack of food due to snow or ice cover on land. Not just deer but also cattle. In years when hay was scarce or rotted in the barns due to wet weather the islanders would feed the cattle seaweed. They didn’t taste great but they lived just fine. Climate change my butt.

HD Hoese
Reply to  Philip Finck
April 25, 2019 10:08 am

I recall meeting someone on a beach collecting seaweed (red, I think) to sell in Nova Scotia (1997) and buying some in a store, some different name used that I forget. I think I was the only one who ate it.

Isotopes are used a lot now to determine diet (habitat), not sure how much verification has been done, these somewhat skeptical with solutions (Phillips, D. L. and J. W. Gregg. 2001. Uncertainty in source partitioning using stable isotopes. Oecologia 127:171–179; 2003. Source partitioning using stable isotopes: coping with too many sources. Oecologia 136:261–269).

April 25, 2019 9:20 am

Bobbing the antlers off the reindeer didn’t help their ability to break ice.

April 25, 2019 9:32 am

“They’re shorter, smaller and much more sedentary than their cousins on mainland Europe and North America, too. All these characteristics make them much more physiologically efficient”

They fail to mention the main reason that Svalbard reindeer have short legs (they are known as “dachshund reindeer”) and are much less mobile than other reindeer. There are no wolves or other predators there.

Incidentally there was once a similar reindeer population on Franz Josephs Land. They died out about 4,000 years ago when climate grew colder.

April 25, 2019 7:34 pm

When do we start seeing aquatic reindeer diving for seaweed?

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