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An odd - look snowy bear with patches of brown pelt was shot by hunters in 2006 and found to be a cross between a diametrical bear and a Ursus horribilis bear . on the face of it , Ursus horribilis were moving north into polar bear territory . Since then , several intercrossed animals have appeared in and around the Arctic , include narwhal - beluga hulk and mixed porpoises .
The culprit may bemelting Arctic ocean ice , which is causing barriers that once secern maritime mammals to disappear , while the thaw satellite is constitute habitat once too cold for some animals just correct . The resulting hybrid creature are threatening the endurance of rare frigid animal , according to a comment published today ( Dec. 15 ) in the journal Nature . [ Real of Fake ? 8 Bizarre Hybrid Animals ]
A spotted seal leaves the ice flow after NOAA researchers recorded information about her and attached a small satellite tag to her rear flipper during a spring 2009 expedition to the northern ice on the NOAA ship McArthur II.
A squad led by ecologist Brendan Kelly of the National Marine Mammal Laboratory counted 34 possible hybridizations between distinct population or metal money of Arctic marine mammals , many of which are endangered or threaten .
" The keen concern is coinage that are already imperiled , " say Kelly , first generator of the Nature gossip . " Interbreeding might be the last straw . "
Pizzlies and Narlugas
When hunter play a cross of a polar bear and a silvertip in 2006 , Kelly ’s colleagues notice that the incident was just a fluke . But as Kelly delved into the issue , he found more grounds of similar anomaly . In 2009 , a cross between a bowhead and a right whale was spotted in the Bering Sea , between Alaska and Russia . And a museum specimen in Alaska evidence to breeding between spotted seal ( Phoca largha ) and medal seals ( Histriophoca fasciata ) , which belong to unlike genera , a scientific classification of organism that is broad than the species level .
grounds suggests at least five other types of hybrids that may originate from animals of distinguishable genera , Kelly ’s squad reported . These include :
Breedings between these marine mammals near the North Pole are probable to lead in prolific offspring , because many of these beast have the same routine of chromosomes , say gossip co - generator Andrew Whiteley , a conservation geneticist at the University of Massachusetts , Amherst .
Chromosomes that are one in number can not pair during miosis , a limited type of prison cell division necessary for intimate reproduction . During reduction division , chromosomes duplicate and the cell divides to imprint daughter cells , which break up apart to imprint gametes , or mature intimate reproductive cell . But with unmatched chromosomes , the schism into gamete would be scratchy , creating sterility .
Over the short term thehybrid offspringfrom these Arctic creature union will likely be inviolable and sizable , because unlike inbreeding , which magnifies hurtful cistron , so - bid outbreeding can mask these genes . Most of these genes are recessive , have in mind the materialisation need a pair to in reality show the trait . Different coinage or dissimilar genera generally do n’t have the same bad recessive alleles , and so there ’s not a high chance of a yoke turning up . ( Alleles are different versions of the same cistron . )
But over time , as the hybrids pair randomly , those harmful cistron will come out of hiding and make the offspring less fit and less capable of surviving , Whiteley warned .
Kelly said that breeding between mintage usually is n’t beneficial when it ’s induce by accelerated environmental change , because the intercrossed animals do n’t have meter to evolve survival trait . " This change is happen so apace that it does n’t predict well for adaptive response . "
For instance , a crossing between a narwhal and a beluga whale spotted in Greenland lack the narwhal ’s spiral tusk , which give to breeding winner . The arctic – grizzly hybrid bears in a German menagerie showed behaviors associated with cachet hunting , but not the strong swim abilities of polar bears .
Animals already threaten with extinction could take a hit from hybridization . The breedings between the North Pacific right giant , whose numbers have fall below 200 , and the more numerous bowhead whale , could push the former to extinction . ( Over clip , the hybrids would set out to outnumber the thin right hulk . )
Climate Crisis
" This is one of the consequence of the rapid alteration we ’re induce in that environment and one more reason to regard whether we really need to continue warm the climate as apace as we are , " Kelly tell LiveScience .
The Arctic Ocean may lack summertime ice by the closing of the 100 , " removing a continent - sized roadblock to interbreeding , " the investigator wrote . As such , Kelly and his collaborators urge scientist to mold the prevalence and outcomes of hybridisation , genetically supervise at - peril universe , and generate a priority list .
And they ’re agitate policy - makers to incorporate hybrids into their management and protection plans . Currently , the Endangered Species Act does n’t protect intercrossed creature , Kelly said . " It ’s just not something that has been on people ’s radar screen , and we remember it should be . "
