IT IS a debate that has been raging for years.

Exactly why does Rudolph have a red nose? In the past, scientists believed the reindeer’s red nose was due to an excess of blood vessels clearly caused by pulling such a heavy load of Santa, his sleigh and all those gifts.

But now boffins at the University of Brighton have come up with a new explanation – bioluminescence.

This is the production of light as a result of a chemical reaction, similar to that produced by fireflies and some deep sea organisms that use light traps to catch prey.

The study may appear frivolous but it has proved a valuable exercise for the university’s biology students. And the findings have been deemed worthy enough to be published today in DEINSEA, an online journal of the Natural History Museum in Rotterdam.

The research was led by Dr Angelo Pernetta, a conservation ecologist and deputy head of the School of Pharmacy and Biomolecular Sciences. He said: “The paper is a light-hearted response to a previously published paper, which discussed why Rudolph had a red nose. It has already proved a very valuable experience for the students involved. One student recently secured a funded PhD studentship at Warwick University and he mentioned his involvement in the production of this paper definitely played a part.”

The previous paper, published in DEINSEA in 2012, identified the cause of Rudolph’s nose glow as “nasal mucosa induced by the exertion of pulling a heavy load: excessive stresses endured while flying with Santa and the sleigh in tow resulted in cerebral and bodily hyperthermia, overworking the nasal cooling system, causing the nose to glow”.

But the new study says: “While we recognise the central tenet of highly vascularised nasal mucosa in reindeer helping regulate nasal heat exchange, we concluded that this is unlikely to be the causal factor of Rudolph’s particularly iridescent appendage for multiple reasons.”

Their conclusion was: “The fact that Rudolph’s nose glows red has previously been noted as being advantageous in foggy conditions, since it is the most visible colour in fog. A 1939 paper noted that Rudolph’s glowing nose aided Santa Claus in his Christmas Eve preparations when a thick fog descended.

“This would suggest that Rudolph was specifically chosen because of this adaptive trait and would suggest that, far from being caused by excessive strain from pulling Santa Claus and the sleigh, his red nose was in fact caused by bioluminescence to aid in navigation.

“We believe we have found a scientific answer to this age-old question. Now all we need is to do is discover how Rudolph and his fellow reindeer manage to fly.”