BRAS D’OR BIOSPHERE: The Pleistocene Biosphere

As you hike through the forests of the Bras d’Or Lake Biosphere, stop, close your eyes and imagine what you would see if you could be transported back to another time.

One thing that we know for sure is that you would be sharing the forest with massive mastodons if you chose to appear during the Pleistocene era, before the last ice age. These previous residents have left pieces of a large puzzle which can help us draw pictures of our biosphere in the past. Stories and legends passed down by the biosphere’s early residents help us colour those pictures.

One such picture involves an industrious farmer named Alexander MacKay. In 1834 he was working his field near Middle River when he stumbled upon one of those puzzle pieces. He found the femur (leg bone) of a Mastodon which was later radiocarbon dated at 75,000 years before the present. I can’t imagine what that poor farmer must have been thinking when he discovered that massive leg bone. The extinct mammal was dubbed “Big Sandy” which was Alexander’s nickname. The rest of Big Sandy’s skeleton (the mastodon, not the farmer) is probably still there, buried under the forest or the many layers of mud and rock on the river bed.

So, let’s imagine what Big Sandy’s biosphere might have looked like. According to our best scientific guesses, the climate would have been cooler, with snow falling at all times of the year. The forests were populated by softwoods, and tender spruce boughs would have been a staple of Big Sandy’s diet. Because sea level was 5 to 7 metres higher then, the Bras d’Or estuary was larger. Much of the present lowland area was under water and the Boisdale Hills were islands. There is evidence that this larger Bras d’Or estuary was connected to the Atlantic Ocean along the Margaree Valley, the Mabou estuary and (perhaps) through East Bay to Sydney Harbour. The shape of the estuary was quite different than it is today, as determined by geologists John Shaw, David Piper and Bob Taylor in a report published by the Nova Scotia Institute of Science in 2002.

Big Sandy wasn’t alone in the Pleistocene Biosphere. Other fossils have been discovered. In May of 2014 Lawrence MacNeil and Sandy MacLeod discovered more Mastodon bones during an excavation at the Little Narrows gypsum quarry. That Mastodon has been named “Mac” by the students at the nearby Whycocomagh Education Centre and the bones now reside at the Nova Scotia Museum of Natural History in Halifax alongside Big Sandy’s femur. You can watch museum geologist John Calder talk to the Whycocomagh students about the discoveries under our feet waiting to be made here: https://www.youtube.com/watch?v=7HET7s_W_0c.

You should visit these biosphere puzzle pieces at the new Mastodon exhibit at the museum when you are in Halifax. The museum has a special place for Big Sandy from the Bras d’Or Lake Biosphere because his femur was already in their possession when they formed as the provincial museum of Nova Scotia in 1868. You can see the famous femur from Middle River on the museum’s Web site: https://museum.novascotia.ca/blog/1834-mastodon-femur.

So, as you are standing in the forest with your eyes closed, are you picturing huge, wooly elephants walking beside you? Let’s be clear. Big Sandy, Mac and all of their friends are mastodons, not wooly mammoths. Mastodons were shorter and chubbier than wooly mammoths with shorter, straighter tusks. Mastodons were wood browsers and their molars are pointy. Mammoths were grazers and their molars are flat for eating grass. They did co-exist in some parts of North America but we don’t have any evidence that they were neighbours in our biosphere.

However, when Big Sandy roamed the forests, he could have been joined by other giant mammals such as beavers the size of black bears. Fossils of this enormous rodent have been found all over North America, including Indian Island, New Brunswick according to a report by Miller, Harington and Welch in the science journal Atlantic Geology published in 2000. No giant beaver fossils have been found in our biosphere but there may be a link between that famous femur found in Middle River and the giant beaver. According to Mr. Speck writing in the American Journal of Folklore published in 1915, a Micmac named Td’mekian (Tom Stevens) a long while ago found giant beaver bones in Middle River (ribs eight feet long). Although these remains are supposed to be in the Museum at Halifax according to Mr. Speck, there is no record of them arriving. Perhaps the fossils were those of Big Sandy, and not a beaver after all.

If you find the bones of residents from our ancient biosphere, be aware that all fossils are protected in Nova Scotia by the Special Places Protection Act. If you find a bone or tooth that you suspect is a fossil, please contact the museum.

Dr. Annamarie Hatcher

Dr. Annamarie Hatcher is a consulting ecologist and a board member of the Bras d’Or Lake Biosphere Reserve Association. For more information about the Bras d’Or Lake Biosphere Reserve Association, please visit http://blbra.ca/.