November 22, 2016

The Animal Rodney Dangerfield

The golden-mantled ground squirrel doesn't get much respect. It was true in the 1950s and it's still true today.  These two videos prove it, and wow... looks like our attention span has gone from over 10 minutes to a mere 26 seconds!

Squeak, the Squirrel (1957)
Golden-mantled ground squirrels - Banff National Park (2014)

And, speaking of no respect, don't get us started about the Crasher Squirrel meme.

So we, Nadine and Joel, felt that it was time to raise the profile of this most photogenic of wildlife species. Let's give ground squirrels some respect, starting with the amazing story of their winter hibernation. While in their dens, they:

  • drop their core body temperature over 30 C, down to the ambient temperature in their dens (likely 1-3C).
  • reduce their heart and breath rate to 5-10% of normal.
  • have a metabolic rate below 5% of their active rate.

But they don't stay at these extremes all winter long. About every two weeks, they rouse themselves fully. Biologists have long wondered why. Their latest idea is that it's all about staying smart – the brain needs to repair itself.

A Scientific American article from last year describes it like this: “Hibernation devastates the ground squirrel brain, wilting thousands if not millions of vital connections.... But its brain has evolved impressive resilience, repeatedly renewing itself at astonishing speeds, like a forest erupting through the scorched earth in a matter of days.”

The idea is that allowing the brain to degenerate  reduces energy demands on a day to day basis. But that can't be allowed to go too far. The brain runs the risk of permanent damage. So, every few weeks the squirrel comes out of deep hibernation and the brain “blooms:”
“Whereas neurons in hibernating brains looked like barren tree limbs in the dead of winter... in only two hours the squirrels' brains had not only compensated for all the synapses lost during hibernation—their brain cells now boasted many more links than those of an active squirrel in the spring or summertime.”
One day later, they were back to being barren trees.

We don't yet know how they do it. It's an amazing story and one worthy of respect!

Respect also grows when you find out that ground squirrels are almost on a par with bears when it comes to medical interest in how they hibernate. More and more scientists are studying them to find treatments for ailments like heart attacks and stroke, diabetes, bone loss, and brain degeneration (Alzheimer's disease for example). They are also looking at ways to extend the shelf life of organs for transplant. Many of those scientists, like Ken Storey, are Canadian. After all, we're a land cold enough to have hibernators, eh!

These researchers are looking at the many amazing ways that hibernating animals reduce their energy demands and put themselves – safely – into a state of suspended animation. A hibernating animal is dealing with starvation, hypoxia (oxygen deprivation) and low blood flow in hibernation, and the need to quickly gain weight before hibernation.  To do it, they must transform themselves in many ways.

The list includes change at the cellular level (turning genes on and off; changes in the biochemistry of cell function) and at the macro level (shrinking organs; partnerships with microbes; adding haemoglobin to the blood... and much more). There's so much to learn that has medical implications.

So, the next time you are tempted to take that oh-so-cute snap of a ground squirrel... think twice! And take that picture with respect.