MPR has a fascinating report on that iconic Minnesota animal – the moose – and how it’s shrinking:
When scientists at Michigan Tech University examined the skulls of 662 moose killed by wolves over the past four decades at Isle Royale National Park, they discovered something surprising.
Over those 40 years, the size of those skulls had shrunk by 16 percent, even as the moose population on the Lake Superior island flourished, tripling in the past decade to about 1,600 this year.
The findings, published recently in the journal Global Change Biology, are part of a long-running study on the predator-prey dynamics between moose and wolves on the remote island, located about 25 miles off the tip of northeastern Minnesota.
The biggest reason researchers attributed to the decline in moose size is the increasing density of moose on the island, as the wolf population has collapsed. Researchers now say there may only be one wolf remaining on the island.
The study found that skull size was smaller for moose born in years when moose were more abundant, because more moose means less food for each animal.
Adaptation at work. I wonder how much more they have to shrink before they are considered a new species. This reminds me of the study of the pygmy mammoths of the Channel Islands of California, who also shrank down until they were roughly 1/20th the size of their ancestors.
