Now imagine a geological and climatic change that effectively splits that society in two. A huge icy mass fills the only path between the groups. It remains for generations, becoming a permanent fixture that physically separates the two populations. But lives go on. Families continue to grow. Traditions, hunting practices, and languages evolve separately — perhaps diverge.
Then one summer day, 10,000 years later, a single member of one of those now-distinct groups is out hunting. He works the western edge of his hunting grounds – an area normally bounded by the ice barrier – but today he notices it has broken down. There are gaps he can traverse. So he wends his way through the ice and soon finds himself in a whole new domain. There, to his surprise, he finds another of his kind – a member of the tribe that has been separated from his for the last 10 millennia.
This is exactly what happened just last month in the northern Canadian Arctic. Because of the loss of Arctic sea ice and the opening of the Northwest Passage, two bowhead whales (Balaena mysticetus) , one from the Pacific and one from the Atlantic, suddenly found themselves sharing the waters of Viscount Melville Sound and the Parry Channel in the Canadian Arctic Archipelago for the first time in 10,000 years.
This encounter raises all kinds of scientific questions and worries. There is, of course, the overarching concern about climate change and the loss of arctic sea ice. And there are the more local concerns — the spread of disease; the mixing of the ocean waters and other marine organisms; and the increased possibility of detrimental hybridization that has already occurred in some species.
Interbreeding between the North Pacific right whale, of which there are probably fewer than 200, and the more numerous bowhead whale could quickly push the former to extinction. (2010 Kelly, et al)
But when I read this story, my mind went to the social questions. These are not stupid animals. They are complex creatures with language and behaviors that are passed down through the generations. Being blatantly anthropomorphic for a moment, I want to know what they said to each other. Did they greet each other routinely or was their excitement in their voices? Was it a meeting of friends or strangers? Did they even speak the same language? Do they have Atlantic and Pacific accents?
The whales were, at their closest, 130 km apart– two days travel for a bowhead. But bowheads are a vocal species. Their low frequency calls can penetrate miles of ocean. These whales would have had no trouble hearing each other at such a distance. In fact, scientists are puzzling over why the whales came to this area to begin with, since it is a poor feeding ground. Could it be that they called each other there? (This also makes me wonder if the whales have been “talking” through the ice for hundreds or thousands of years.)
And I want to know if there has been any divergent evolution in these two groups. They are virtually alike genetically, but what about behaviorally? Have they been exposed to different environmental factors that may have caused changes to their behaviour? For instance, do they still have the same hunting and anti-predator strategies? And if not, does one population now have a selective advantage over the other?
Alright, I’ll grant that there is probably no major difference between the populations and that the meeting of the two whales is more meaningful to scientists (and to me) than it is to the whales, but I am intrigued by the whole idea that these animals, so long separated, are now reunited and have 10,000 years of catching up to do.
Imagine the stories they would tell, if only they could. From their recent memory, they would certainly talk about the 400 Year Slaughter, the period from the 16th to the early 20th century when generations of bowhead families were lost to commercial hunters. The Pacific whale, if he is old enough might even be one of the last 1000 of his kind to have survived those hunts. Given that he is a member of a species that lives upwards of 150 years (possibly more than 200 years), this isn’t a farfetched conjecture.
One [bowhead whale] was 91, one was 135, one 159, one 172, and the oldest whale was 211 years old at the time of its death. That whale, alive during the term of President Clinton, was also gliding slowly and gracefully through the Bering, Chukchi and Beaufort seas when Thomas Jefferson was president. (Ned Rozel, Alaska Science Forum)
The Atlantic whale would have a similar story – he too a member or a descendant of a remnant population. Before commercial exploitation of bowheads began, it is estimated that 30,000-50,000 of whales existed worldwide, divided roughly equally between Atlantic and Pacific populations. By 1926 when commercial whaling of bowheads was made illegal, there were only 3,000 left. Today, only subsistence whaling is permitted and some bowhead populations are recovering. Current estimates put the global population between 7,000 and 10,000 animals.
Whether they talked or not, in September 2010, after nearly two weeks of hunting the same waters, the two traveling bowheads turned and swam back to their normal summer feeding grounds. I’d like to think that when they returned to their families, they each had a story to tell about meeting a lone traveler and distant relative in a newly-opened sea.
George, J., Bada, J., Zeh, J., Scott, L., Brown, S., O’Hara, T., & Suydam, R. (1999). Age and growth estimates of bowhead whales(Balaena mysticetus)via aspartic acid racemization
Canadian Journal of Zoology, 77 (4), 571-580 DOI: 10.1139/z99-015
Givens, G.H., R.M. Huebinger, J.C. Patton, L.D. Postma, M. Lindsay, R.S. Suydam, J.C. George, C.W. Matson, & JW Bickham. (2010). Population Genetics of Bowhead Whales (Balaena mysticetus) in the Western Arctic Arctic, 63 (1), 1-12
Heide-Jorgensen, M., Laidre, K., Quakenbush, L., & Citta, J. (2011). The Northwest Passage opens for bowhead whales Biology Letters DOI: 10.1098/rsbl.2011.0731
Kelly, B., Whiteley, A., & Tallmon, D. (2010). The Arctic melting pot Nature, 468 (7326), 891-891 DOI: 10.1038/468891a