In 2019, the New Scientist LIFE magazine wrote about the superpowers of reindeers. Do they really have superpowers?
The Reindeer, or Caribou, is a large mammal in the Cervidae family of deers. Nearly 5 million Reindeers live in the freezing climate of the Arctic, from Alaska to Siberia and Greenland, where there are more periods of night-time darkness than day-time light.
Genetic scientists know that Reindeers can change the colour of their eyes from gold in summer to blue in winter. They are also working on the Ruminant Genome Project to study Reindeer genes – their DNA – to compare their genes to human genes and other animals, especially other ruminants. Ruminants are animals that chew their cud, such as deer, cattle, goats, sheep, giraffes, gazelles, and antelopes.
In 2019, a study at the Chinese Academy of Agricultural Sciences and the University of Denmark, as part of the Ruminant Genome Project, found that many of the same genes involved in Reindeers’ adaption to living in the Arctic environment are the same in humans.
For example, humans and most other animals have daily rhythms of activity and rest linked to light and dark – such as being active when it is light and sleeping when it is dark. This is called the biological clock (biological rhythms) or the circadian clock (circadian rhythms).
Reindeers can do this too, but they can also override their biological clock. When there are 24 hours of daylight in the Arctic summer, Reindeers forage for food at all hours, day and night. When there are 24 hours of darkness in the Arctic winter, Reindeers are hardly active at all, but they don’t sleep a lot even though it is dark. They ‘break’ their biological clock, just like other animals that live in the Arctic, such as Emperor Penguins and Polar Bears.
The Ruminant Genome Project study found that Reindeers have unique versions of genes that operate their circadian clock. One key protein, called Per2, mutates (changes) so that other circadian proteins can’t bind or stick to it, says Rasmus Heller at the University of Denmark.
Humans don’t have a gene to break their circadian clock, but learning about the gene variants could help humans to overcome jet lag (re-adjusting to light and dark cycles across time zones after travelling long distances). Knowing about the effects of disrupted circadian rhythms could help humans learn more about mood disorders too, such as insomnia (sleeplessness) and depression.
[Other scientists think that Santa’s Reindeer don’t have jet lag when flying all over the world at night-time in December because they have a super-powered circadian clock – they are not affected by 24 hours of darkness.]
Location of photographs: London Zoo, England
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM