Every Thanksgiving, before she sets the turkey in the oven, Tracey and I go to the zoo to see the elephants smash giant pumpkins. The “Great Pumpkin Stomp” never disappoints. The pachyderms squash with tusk and foot, busting the oversized fruit into chewable chunks. And aside from the vegetable carnage, the event is an excellent opportunity to admire the elephant’s trunk.
When Christie the African elephant wandered near the fence to chaw on one of the larger pumpkins during last year’s stomp, I was mesmerized by the dexterity of her nose – the subtle expansion and contraction of muscle that let her carefully feel around the rind for the right edge as well as get enough of a grip to rip off a loosened piece and lift it to her grinders. And, as often happens in such situations, my thoughts turned to the prehistoric. How wonderful it must have been to watch the grace and power of a mammoth’s trunk.
I’m 4,000 years too late to watch mammoths wield their useful appendage, but, being that they disappeared practically yesterday, paleontologists have uncovered several woolly mammoths with trunks still intact. One such mammoth, nicknamed Yuka, was pulled from the permafrost near the Kondratievo River in 2010, and now paleontologist V.V. Plotnikov and colleagues have described how the woolly mammoth’s trunk differed from those of living elephants.
Plans for Yuka’s exhibition led Plotnikov and coauthors to examine the young mammoth’s preserved trunk. The plan was to take her intact skin and “produce a full-size stuffed mammoth, like that of the Berezovskii mammoth”, which had been mounted over a century ago. This effort is what let the researchers pick up their scalpels, excision knives, and trident hooks to dissect the amazing appendage.
Yuka’s trunk wasn’t exactly as it had been in life. Her skin shriveled during the dry process, reducing her trunk’s length from 40 inches to 32 inches over nine months. Still, despite the shrinkage, much of the trunk’s internal and external landmarks could be seen. For example, the end of Yuka’s trunk had two finger-like projections that were longer than those of modern elephants. These “digitiform processes” are thought to have afforded mammoths a finer grip on the grasses they grazed on as they trundled over the frigid steppe.
The trunk of a modern elephant (top) compared to that of a woolly mammoth (bottom). From Plotnikov et al., 2015.
But the most striking difference between Yuka’s trunk and those of the pumpkin-smashing elephants that inspired this post was a strange expansion of flesh about a third of the way up the trunk. Flaps of skin on either side make a shape reminiscent of a cobra’s hood, Plotnikov and coauthors report, and this has been seen on two other mammoths, as well. What was this for?
Plotnikov and colleagues propose two, non-mutually exclusive ideas. The one they spend the most time considering is that the flaps acted as a snow heater. In the depths of winter, mammoths may have had a difficult time finding unfrozen water. In a pinch, they could have curled a little snowball into their trunk and the warmth of the expanded surfaces would have melted the snow. Not that such a biological heater would have only been useful for staying hydrated. The beasts could have curled the tips of their trunks back up into this pocket – a cozy “fur mitten” that would have allowed mammoths to avoid frostbite on their dextrous snouts.
Of course, in trying to reconstruct the lives of extinct creatures, we’re left with the question of what an animal could do with what it actually did. In many cases, we’re constrained by the limits of what bones and traces fossils can tell us. But with mammoths, there’s at least a slim hope that we might find out if the elephants used their trunks in the ways Plotnikov and coauthors propose. Cave artists were apparently as taken with mammoths as we are, and their illustrations have helped provide an independent check on what the living animals looked like. Perhaps the answer for what the mammoth mitten was used for doesn’t rest in anatomy, but in art.
Reference:
Plotnikov, V., Maschenko, E., Pavlov, I., Protopopov, A., Boeskoro, G., Petrova, A. 2015. New data on trunk morphology in the woolly mammoth, Mammuthus primigenius (Blumenbach). Palaeontological Journal. 49, 2: 200-210. doi: 10.1134/S0031030115020070
