The Most Magnificent Mammals
Reading the article in the New York Times on October 8, 2020 about the sale of one of the most complete Tyrannosaurus rex skeletons, Stan, so designated for the first name of the paleontologist who uncovered its bones and assembled it, I thought about the threat to our current giant creatures. The sale of this most complete T. rex to an anonymous buyer, thought to be in the Middle East, for 31.8 million dollar is, unless it is gifted to a museum, a testimony to the triumph of hubris (the buyer) and greed (Christie’s and its client) over public good. Apparently, the fossil market has become attractive to private buyers, risking pricing museums out of the bidding. One can only hope the rising temperatures of the earth treat our species more kindly than did the Cretaceous-Tertiary Extinction event of approximately 66 million years ago that did in all the many non-avian species of dinosaurs. (Avian dinosaurs or birds are not extinct, obviously.) The non-avian dinosaurs had a good run, approximately 125 million years. The latter Extinction was apocalyptic; the former, global warming, is death by a thousand cuts including tropical cyclones, hurricanes, tsunamis, floods, tornadoes, droughts, wild fires, loss of coastal communities, loss of critical habitat (e.g. Amazon and Arctic) and more.
Returning to the largest mammals, the hierarchy starts with (i) the blue whale (up to 150 tons and 100 feet long), the largest animal ever to roam the earth or seas, made possible by the buoyancy provided a sea creature. Next in weight sequence is (ii) the African elephant (up to 7 tons). It is followed by (iii) the killer whale (orca), a species of dolphin (up to 6 tons). Next in size is (iv) a pinniped or fin-footed mammal (e.g. walrus, fur seals), the southern elephant seal, the largest terrestrial meat(fish)-eating mammal (up to 4.5 tons), outweighing lions, tigers and bears. Pinnipeds live in the ocean but spend extended periods of time on land. The next in weight is (v) an even-toed ungulate (e.g. deer, cow, pig), the hippopotamus (up to 4.5 tons), followed by (vi) an odd-toed ungulate (e.g. horse, zebra), the white rhinoceros (up to 2.5 tons). Those are the top six mammals in size based on weight. (The giraffe is the largest even-toed ungulate if one considers only height).
Figure 1. A typical perch for seal hunting. Image was taken in 1980 by Franz Camenzind former director of the Jackson Hole Conservation Alliance, Jackson, Wyoming and a nature photographer.
I would like to consider the seventh largest mammal in more detail, the polar bear, in part because it is the one that is part of the North American ecosystem (Alaska and Canada). The loss of the Arctic ice cap is proceeding unabated. As we try to grapple with greenhouse gases CO 2 and methane, generated from first world countries, nitrous oxide (N 2 O) is being generated in vast amounts in Africa, Asia, and South America as those continents try to feed their population growth by increasing the use of nitrogenous fertilizers.
The sea ice in the Arctic is critical habitat for polar bears because they hunt seals from a perch on ice, awaiting the appearance of a seal seeking air in the cracks between ice sheets. (Figure 1) The polar bear, despite long intervals of sedentary behavior each day, requires an enormous 12,325 calories per day in its diet. They depend exclusively on seals for their sustenance. They “still- hunt”, perched for hours on ice, and when a seal surfaces they rise on their hind legs and whack the seal with both front paws and, so stunned, they grasp it by the neck in their teeth and bring it onto the ice to feed. Some sustenance can come from a rare whale carcass, but seal hunting is their principal food source. Polar bears, also, make their dens on ice covered by deep snow banks, where they hibernate and have their cubs. Cubs usually are tied to their mothers for approximately two years before becoming independent. The male polar bear is of no help and can be a threat.
Figure 2. On the right is mother and her cub on the move. Four decades of warming since these images were taken have severally threatened this magnificent tundra. This image was taken in 1980 by Franz Camenzind former director of the Jackson Hole Conservation Alliance, Jackson, Wyoming and a nature photographer.
The Arctic has warmed twice as fast as the rest of the world resulting in a decline of sea ice of 13 percent each decade since 1980. Ice forms later in the fall and breaks apart earlier in the spring. The average temperature over the past 12 months ranked as the second-highest value since 1900, resulting in sea ice cover declining in thickness and extent. When the jet stream randomly sends warm southerly winds north, it keeps thinned sea ice from freezing. These enormous gaps in ice require bears to swim long distances to find ice on which to perch for seal hunting. Moreover, the large gaps make the appearance of seals within reach much less frequent.
The denial of climate change, global warming and its consequences, and its inevitability is akin to the claims of the flat earth society, a group that has had trouble garnering members with images of earth from space, although the die-hards argue it is the distortion of the lenses used that gives the earth a spherical appearance! When, Mar-a-Largo is in the Atlantic, there may be acceptance, but we cannot wait that long. The refusal of a Supreme Court Justice candidate to agree that the ongoing global warming calamity exists is frightening testimony to the suppression of fact to meet selfish goals. The Trump administration is opening up the Arctic National Wildlife Preserve to oil and gas exploration. This 20 million acre reserve is home to polar, grizzly and black bears, moose, caribou, tundra Dall sheep, muskoxen, wolves, eagles, lynx, wolverines, marten, red foxes, polar foxes, river otters, porcupine, muskrats, minks, beaver and habitat for many migratory birds. The marine ecosystem is as significant as the terrestrial one and it is threatened. The Preserve was established by President Theodore Roosevelt in 1903 and carefully protected by every administration since the arrival of the current one. Now, oil and gas exploration is being proposed with oil leases to follow. A double whammy is at hand: a severe threat to this magnificent wilderness and more fossil fuels to advance global warming.
Written October 2020