Kate – The Cairngorm Reindeer Herd

10th September 202114th August 2024

Through the Eyes of a Reindeer

A visitor recently asked me why reindeer have horizontal pupils. The question had me thinking about the importance of vision to reindeer. It is easy to forget that many animals don’t see the world the same way we do, and reindeer eyes are in many ways different from our own.

Reindeer live in arctic and sub arctic regions that experience hugely variable light levels. Above the arctic circle, they’ll experience 24 hour darkness in winter and 24 hour sun in summer, and no matter how dark it is, they still need to be able to find their food and see predators coming. So how do reindeer eyes cope with their environment?

When you look at a reindeer, the most obvious thing about their eyes is that they are placed on the side of their heads. This is common in prey animals, and it gives them a wide field of vision that means they can see danger coming from almost any direction. The placement of their eyes does mean they have a blind spot right in front of their noses, but aside from this it’s very hard to sneak up on a reindeer!

If you look a bit closer, the next thing you might notice – aside from their beautiful eyelashes – is that they have long, horizontal pupils. This adaption helps focus a reindeer’s sense of sight at the ground level and the horizon – where their food and their predator’s are found. These horizontal pupils also help compensate for the placement of their eyes and reduce the size of that blind spot in front of a reindeer, so that they can see forwards – vital for finding an escape route when on the run from a predator.

If you looked deeper into a reindeer’s eyes, you would find even more amazing adaptions. In 2013 scientists discovered that reindeer eyes actually change colour with the seasons! A layer of tissue in the retina changes from a golden colour in summer to a deep blue in winter. This change means that less light is reflected back out of the eye, helping reindeer keep their vision sharp even in the long dark winter months. This is the first time this kind of colour change in a mammalian eye has been found. It is thought the colour change might be caused by increased pressure in the eye in winter. The pupil is permanently dilated in the dark, and this reduces the space in the collagen structure of the retina, which in turn changes the reflectiveness of the retina and shortens the wavelengths of light being reflected.

*Two dissected reindeer eyes, the left taken from a reindeer that died in winter, the right from one that died in summer. Photo by Glen Jeffrey (The Independent)*.

Reindeer vision is made even more interesting by the fact that they can see into the UV range. There are high levels of UV light present in the polar regions of the world due to the reflections from snow and ice. Many lichens – the favoured winter food of reindeer – are very effective at absorbing UV. Wolf fur as well is also shown to absorb UV, so being able to see UV wavelengths helps reindeer pick out both their food and their predators in the snow (see here for a previous blog on UV vision).

Reindeer seem to view the world quite differently to us, and it’s clear their eyes have had to adapt to many challenges. They’ve had to adapt to pick out predators and hard to find food, to cope with extreme seasonal changes in light, and to deal with the large amount of UV present in the arctic. Their eyes are just another example of how well adapted reindeer are for their environments.

Kate

Sources:

Why do animal eyes have pupils of different shapes? | Science Advances (sciencemag.org)

Arctic reindeer extend their visual range into the ultraviolet | Journal of Experimental Biology | The Company of Biologists

Shifting mirrors: adaptive changes in retinal reflections to winter darkness in Arctic reindeer | Proceedings of the Royal Society B: Biological Sciences (royalsocietypublishing.org)

13th July 201823rd July 2024

Tales of a Reindeer Herder: Kate’s first day

For the previous few months we have been joined by a new reindeer herder called Kate who helped us out over the busy calving period. Kate was so brilliant to have around we asked her to stay a little longer until some of our regular summer staff returned through June and July. We expect to have her back at some point in the near future, but for now she has headed off to enjoy some summer wanderings. Before she left Kate wrote some lovely short stories about her time herewith some excellent drawings. Keep an eye out over summer for the next installments of her stories. Hopefully we can have Kate back here at Reindeer House in the autumn!

Kate taking Lulu and the twins out for some grazing accompanied by Glenshee

First day on the job – Lost in the fog

During the first hour as a reindeer herder I had managed to become a very soggy, panting mess who was lost in the fog somewhere on windy ridge with not the foggiest where the herd had gone. I remembered thinking to myself; this has gone terribly wrong- I’m not even going to make it through the first day!

It was mid-April and there were still patches of snow on the hills. My first sighting of the reindeer was brilliant, the whole free range of females were running towards us as we walked over a brow of a hill. It was an amazing sight, and one I won’t forget in a hurry, the reindeer looked beautiful and majestic in full winter white coats and impressive antlers. I was marvelling at what a lovely greeting we got, but Mel pointed out they probably came our way being spooked by something from the opposite direction. Then off we went, it was Mel leading the herd to the lower levels and me bringing u the rear, but unlike the agile reindeer that excitedly skip, gliding over the snow patches I ran behind panting and sank straight into a snow hole (Vicar of Dibley style). Up on my feet again I was wondering how on earth I was to keep up with these four legged creatures when 5 of them decided to go in the opposite direction. Standing in the middle of the groups, I thought I can’t lose reindeer on my first mission and went gallivanting after the strays. Of course being a herd animal , it really says it all , and the wanderers then did a full circle galloping off to join the rest, leaving myself lost in the fog. Luckily it wasn’t long until I found the herd again and the rest of the first day went more smoothly.

Kate

26th August 201613th March 2024

Dinner Date

So there is often great confusion over what reindeer like to nom on and if you ever find yourself in that special situation where your dinner date is a reindeer we would hate for you to be unprepared!

The key to any nice dinner is of course a nice accompanying beverage; reindeer love fresh water from a mountain burn or pool… or even an upland lochan – they turn up their noses at tap water so that’s a big no no, I’ve seen reindeer lap up rain droplets up instead of lowering themselves to drinking the tap water we provide them on Christmas events!

As you guys all know by now from reading all our previous reindeer centric blogs, reindeer themselves are an arctic animal so they like their salad with a northern twist! These guys need arctic/sub-arctic habitat and plants to have happy tummies (think actimel for reindeer!)

Reindeer LOVE lichen… I mean L.O.V.E lichen! Although partial to a bit of tree lichen (you could add it in for flair!) the mainstay for the reindeer are ground growing lichens, they are the only animal excepting gastropods (snails/slugs) to have evolved the digestive enzyme to break down lichen.

Lichen in the forest — Lichen covering the forest floor

Lichen is the main source of food for reindeer in the winter when the rest of the grazing has died back for the year and forms springy carpets at the bases of heathers and sedges up on the mountains here. However, interestingly enough lichen contains barely enough nutrients and energy to sustain a gnat let alone a reindeer. Thus in the winter the reindeer very cleverly slow their metabolism right down and the young stop growing – being a reindeer is very much a feast and famine business.

NB. It may be best to plan a summer dinner with your chosen reindeer.

The summer diet is much more varied, it’ll make for a multi-course experience! Once spring hits, the mountains turn green and all the lush grazing once again unfurls. Reindeer will eat almost anything montane, chewy and fibrous (reindeer have adapted to live off low nutrient arctic plants) – there is a common misconception that a lovely field of grass would float their boats but in actual fact it would be the equivalent of us living off a complete diet of clotted cream and would end in some unhappy digestive systems!

Hornet & Lilac LUSH GRAZING — Lilac and Hornet, roaming around in the lush grazing

Reindeer will graze on an array of montane sedges and heathers as well as leafier vegetation such as birch and blaeberry (wild blueberry) leaves in the summer months. In the autumn reindeer will do anything for a wild mushroom; their digestive system allows them to eat even the super poisonous Fly agaric mushroom, however mushrooms often = drunk reindeer which is more than hilarious!

Reindeer will also eat some rather unusual things to gain nutrients if they are lacking, such as cast antler bone (full of great minerals!) as well as the velvet skin they shed from their antlers in the late summer – yum! We have ascertained that while they will eat their own velvet, they draw the line at anyone else’s!

Kate Velvet Shedding — Kate shedding the velvet from her antlers

Sambar Velvet Shedding — Sambar shedding velvet

Whilst this is the mainstay of a natural reindeer diet, if you’ve visited us here you may know we provide a supplementary feed for the reindeer for several reasons – reindeer are greedy and it ensures we have a lovely visit, we give them a wee bit of a helping hand at times of year when grazing is scarce and finally for half the year we use a 1200 acre enclosure and providing a supplement mix ensures all of our yummy natural grazing can re-grow.

First things first if you’re going to make a mix for your reindeer you’ll need to acquire a cement mixer. It is the sure fire way to make a yummy and well mixed batch, your dinner won’t go well if items are poorly distributed! We like to mix with a tonne of hay-mix (chopped up hay) which is covered in garlic molasses. The garlic is great for the digestive system but it does mean us herders have a garlicy scent most of the time. It can be a very lonely existence this reindeer herding! Next a splash of barley and sugar-beet alongside a general sheep feed full of good grains and our last ingredient is rather special. It’s called dark grains and looks pretty boring BUT is by far the coolest thing in the mix.

It’s a by-product of alcohol distilling (malt whisky production), obtained by drying solid residues of fermented grain to which certain solubles (pot ale syrup or evaporated spent wash) have been added. Unfortunately all the alcohol is all gone by this stage and the dark grains themselves are rather bitter so maybe mix them in well!

One final word of wisdom if you want to posh up your dinner is to sneak some seaweed in there – we discovered the reindeer loved the stuff after it was used to fertilize a patch of tree saplings and they ate it all. It’s now something we regularly provide for the reindeer in our paddocks and enclosure over the summer months.

We wish you the best of luck and hope if you ever have a reindeer date dilemma we’ve provided some key tips to a great evening or you!

Gandi and Puddock with their main course of lichen!

Abby