Grand Canyon National Park issues wildlife safety warning: Watch out for squirrels

[Pivo]

https://www.yahoo.com/news/grand-canyon ... 04025.html

[SuperstitionGuy]

Social distancing from the attack Rock Squirrels is now 50 feet?
That's more than for Rattle snakes that can kill you.

[Alston_Neal]

The little fellas are still pissed at the French.
https://www.dailymail.co.uk/video/news/ ... thugs.html

[nonot]

Surprised that they didn't get 30 people bit in the finger by rattlesnakes...oh wait, people don't tend to feed rattlesnakes and get them to eat from their hands.

[big_load]

Surprised that they didn't get 30 people bit in the finger by rattlesnakes...oh wait, people don't tend to feed rattlesnakes and get them to eat from their hands.

Well, speaking of rattlesnakes, they're clearly not doing their jobs, or there wouldn't be so many troublesome rodents in the Grand Canyon.

[Canyonram]

Yo Squirrel fanatics,

Squirrel teeth are lethal weapons. They are the most important animal injury threat at the Canyon. This video should be on a loop at the Bright Angel snack bar to convince people not to feed the beggars. It ain’t a Walt Disney plotline with the happy little squirrel glad to see your 4-year-old feeding him peanuts. Not a good memory of a trip to the Canyon for anyone. Squirrels hang out on the rock wall and greet thousands of tourists during the summer. When the season ends, they actually invade the BA snack bar and the restaurants along the room looking for those generous tourists.

[ youtube video ]

For a long time, there was a Bobcat (named ‘Bob’ by the Park Rangers—how original) who hung out along the Canyon side of the wall outside the BA snack bar. While the rock squirrels were getting fat and sassy off junk food, Bob got fat and sassy off the squirrels. On occasion, you could see him lounging in the shadow of the wall, only feet away from the tourists and squirrels. (It takes a couple of squirrels to satisfy a redneck from Missouri—got to watch out for the hairs left behind when you skin them).

Squirrels have evolved a degree of immunity against rattlesnake venom in the arms race evolution between predator and prey. Rattlesnakes will eat the young while the adult squirrels have a tolerance even if bitten. Squirrels will mob snakes (including rattlers) and make some daring attacks to chase them away. Next time on the trail, if you see several squirrels chattering away with their tails wagging and twitching while lunging into a pile of rocks—a good chance that there is a snake in hiding. The squirrels appear to distinguish between rattlers and other snakes—I think it might be the warning sound of the rattle from adult rattlers. Of course, some snakes are ‘sound mimics’ and will rattle the end of their tail in perfect imitations of a rattler. Squirrels will totally diss a non-poisonous snake and throw dirt in his face. They are not as bold with rattlers. LOL.

https://pubmed.ncbi.nlm.nih.gov/21184770/

Squirrels can increase the temperature in their tails which in turn helps misdirect a rattlesnake strike—the snake is using its heat sensor organs to determine where to strike. Not much meat on those fluffy tails.

https://www.nsf.gov/discoveries/disc_su ... ttlesnakes.

[ youtube video ]

So, having a squirrel in camp can help drive away rattlers and they will act as watchdogs vs rattlesnakes. Campsite trash and dropped food will draw in mice which will draw in rattlers which sets up warfare between squirrels and rattlers. There are plenty of rattlers living in even heavily-used campgrounds like Indian Gardens and BA going after the mice. So pick a site where the squirrels are relaxed and simply trying to get into your food. Rangers at Indian Gardens have to routinely capture rattlesnakes and move them away from the campsites.

[ youtube video ]

Of course, I have mixed appreciation. My very first Kelty backpack was chewed into as the squirrel went for my goodies. Gnawed a big hole in the bottom of the pack. I chased the squirrel halfway down Clear Creek tossing chunks of rocks in his general direction. Of course, when I got back to camp, his squirrel buddy was helping himself to the exposed goodies. I think it was payback for killing and BBQing their relatives in Missouri. Lesson: Hang pack in a tree if available, leave all zippers open so the squirrels/mice have free access, use a metal mesh bag like a Ratsack (made in Flag), use peppermint oil, and/or hot spicy chips to repel the squirrels. (Save some of that Navajo Taco seasoning). Also, avoid heavily-used campsites---the squirrels and other critters are waiting for your arrival.

[Canyonram]

I failed to mention another interesting finding regarding squirrel/rattlesnake interactions.

Snakes literally taste the air when they flick the tongue and then press the tongue to the roof of the mouth (Jacob’s organs). To confuse the snake, squirrels will chew shed rattlesnake skin and work the pulp into their fur. The female will do this to protect their young. Apparently, this provides olfactory camouflage with the snake ‘tasting’ the presence of another snake and not the presence of a squirrel.

When I first saw a squirrel chewing away on a shed rattlesnake skin, I thought the squirrel was going after minerals/protein/nutrients not found in its normal diet—something similar to a cat chewing down on blades of grass. Work by Barbara Lucas, et.al corrected that notion. If you have access via your library you can read the original research.

Clucas, B., D. H. Owings, and M. P. Rowe. 2008. Donning your enemy's cloak: ground squirrels exploit rattlesnake scent to reduce predation risk. Proceedings of the Royal Society B: Biological Sciences 275:847-852

See the Nature show
https://www.pbs.org/wnet/nature/squirre ... kin/13399/

[Pivo]

@Canyonram
That’s interesting, yet what about their heat-sensing pit organs? If it looks like a squirrel, walks like a squirrel, and emits heat like a squirrel. Must be a rattlesnake?

[Canyonram]

@Pivo
The rattler’s strike is not based on a series of complex mental gymnastics as to when to strike. They don’t have the brain for it. Instead, the strike is a fixed action pattern that is released due to certain external stimuli. In the case of reptiles, the stimuli are single or a small group of attributes of an object, not the object as a whole. These attributes may include color, shape, odor, and sound. Even though the strike is a complex behavior requiring precision to accomplish, it is not one under conscious control. It is an instinctual pattern that is triggered by a few key stimuli.

Animal Behaviorists Konrad Lorenez and Niko Tingberg developed the comcept of fixed action patterns: https://en.wikipedia.org/wiki/Fixed_action_pattern

Congrats on asking the question—you’re on the right track to becoming an ethologist. Short answer---if it doesn't taste like prey, don't strike. A detailed explanation in regards to your specific questions about how rattlesnakes ‘decide’ on when to strike is here (scroll down and you can read the paper online). The paper is a Master’s thesis by Matthew Barbour
https://www.academia.edu/1441414/Conseq ... g_behavior