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Home* News and Stories → Rein­de­er can see wit­hin the spec­trum of UV-radia­ti­on

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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last modification: 2014-07-01 · copyright: Rolf Stange
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