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Daily Archives: 17. December 2013 − News & Stories


Reinde­er can see within the spec­trum of UV-radia­ti­on

News from the world of the reinde­er, who are curr­ent­ly facing hard times in the Arc­tic with the pre­vai­ling polar night. The toug­hest times will, howe­ver, come in spring, when the light returns. By then, fat reser­ves are most­ly used up, but snow and ice still make access to food dif­fi­cult for quite some time.

To sur­vi­ve under such extre­me con­di­ti­ons, reinde­er have deve­lo­ped a num­ber of asto­nis­hing adapt­a­ti­ons. The­se include the abili­ty to see within the UV-spec­trum of light. We humans can see from 400 nm to 700 nm: this is the spec­trum of (for us) visi­ble light, the rain­bow colours. We can­not see any­thing bey­ond, neither wave­lengh­tes below 400 nm (ultraviolet=UV radia­ti­on and shorter) or abo­ve 700 nm (infrared radia­ti­on and bey­ond). Quite oppo­si­te, UV radia­ti­on can be harmful to our eyes and skin (snow blind­ness and sun­b­urn).

Reinde­er can, howe­ver, see wave­lengh­tes down to 320 nm, which is well bey­ond our own ran­ge. It is, howe­ver, unknown what exact­ly they see: colours or greysca­le.

This abili­ty may help reinde­er to find food: important tun­dra plants absorb parts of the UV spec­trum and may accor­din­gly be more con­trast-rich and thus easier to see within the UV spec­trum. Being able to see UV may also make ori­en­ta­ti­on easier in whiteout con­di­ti­ons, when visi­bi­li­ty for humans is redu­ced to almost (or actual­ly) zero. It is not dark, but any con­trast gets com­ple­te­ly lost in true whiteout, so we are then unable to detect or iden­ti­fy objects, distances, ter­rain fea­tures etc. Also pre­da­tors are easier to detect in advan­ce within the UV spec­trum.

With their UV sens­ing abili­ties, reinde­er are no excep­ti­on in the ani­mal world. Simi­lar see­ing ran­ges have been found in birds, bats, rodents and insects. It is quite pos­si­ble that we as humans with our limi­t­ed see­ing abili­ty are the expec­tion rather than the reinde­er.

In ano­ther artic­le, forskning.no reports about the evo­lu­ti­on of reinde­er: the gene­tic diver­si­ty of reein­de­er has deve­lo­ped lar­ge­ly during the ice ages. Split­ting of are­as due to inland ice for­ma­ti­on in North Ame­ri­ca has led to gene­tic split­ting and accor­din­gly an increased gene pool espe­ci­al­ly for tun­dra reinde­er. Tho­se reinde­er living in wood­lands may in con­trast have expe­ri­en­ced a reduc­tion of their gene­tic diver­si­ty during ice sheet growth, when their habi­tat was redu­ced in area and popu­la­ti­ons moved tog­e­ther. Espe­ci­al­ly tun­dra reinde­er may accor­din­gly be quite well sui­ted to adapt to cli­ma­te and habi­tat chan­ges. In the past, they have shown an ama­zing abili­ty to sur­vi­ve a chan­ging envi­ron­ment: they are among­st few spe­ci­es of Qua­ter­nary (ice age) megaf­au­na that has sur­vi­ved until modern times, while mam­mo­th, smi­l­o­don, mega­lo­ce­ros and many others have dis­ap­peared from the pla­net.

Sur­vi­val experts in harsh cli­ma­te: Reinde­er in Spits­ber­gen.

Reindeer, Spitsbergen

Source: Forkning.no (UV-visi­bi­li­ty, gene­tic varia­ti­on)

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