Friday, November 07, 2008


In my last blog I wrote about how California ground squirrels use its tail to defend themselves against predator such as snakes. Specifically, using their abiligty to control the temperature of their tails to confuse rattlesnake that uses infrared radiation to find their pray. This predator avoidance strategy is useful only when the squirrels are face-to-face against a snake. As most of you might have guessed this method may not always be a efficient as the squirrels might hope for. Also, this method of defense mechanism is used mostly by female squirrels grading their young almost similar to what we studied in  class about the behavior of mobbing by Black-headed gulls. In class we discussed the many stratigies used by pray to avoid predation "Predator Avoidance," in this case, the California ground squirrel uses a mixture of two strategies. 
1) Avoid detection- By grabbing the attention of the rattlesnake, the squirrels are about to "avoid detection" of their young ones. 
2) Make capture less likely- The squirrels not only use their tail's heat to confuse the rattlesnake but also "make capture less likely" by using its tail to fight with the snake. 
This time Barbara Clucas, another graduate student in animal behavior, form the same university "UC Davis" found another predator avoidance strategy used by both ground squirrels and rock squirrels in California. Barbara Cluces, observed that these squirrel species
"chew up rattlesnake skin and smear it on their fur to mask their scent form predator,.."
It seems that mostly female and their young ones, just like the use of heated tail, use this behavior of chewing chewing rattlesnake skin. The squirrels don't just use rattlesnake skins, they also use anything that has a snake's odor. She believes that by chewing and spreading the rattle snake skin on their own fur, the squirrels are about to hind their own scent with the rattlesnake scent. By doing so the squirrels are about to sleep a little bit more peaceful at night. 

The article is located at

Posted by Tenzing Y. Dundutsang


At 11:32 AM, Blogger PWH said...

Interesting article,
I have one question about the smearing of the rattlesnake skin though. Does this mean that the preferred sense that a snake uses to detect a prey is its sense of smell? And are there any studies or known statistics of how much more effective a squirrel is when it uses this technique as opposed to when it hasn't?

Ahmed Sandakli

At 3:05 PM, Anonymous Anonymous said...

That's really interesting. Is there a reason that females and younger squirrels employ these defense techniques? Are they more susceptible to predation? This was a really interesting article.

Amy Kawazoe

At 4:37 PM, Blogger PWH said...

It is very interesting that the females protecting their young have these special strategies in predator avoidance and males do not. It is probably an evolved strategy to increase the survival rate of the young squirrels. So, for the technique of acquiring the snakes scent, does the snake avoid other snakes? Does having a scent of a snake block the scent of the squirrel? Interesting topic.

-Carlos A. Varela

At 5:28 PM, Blogger Dan said...

Is chewing of the rattlesnake skin only effective against other rattlesnakes? It seems this method would only work against one type of predator if that was the case.

~Dan Hong

At 6:05 PM, Anonymous Anonymous said...

What else do they use that has the snake's odor? I don't understand how a snake can be tricked with this unless snakes only use odor cues to recognize individuals. If snakes use visual cues then that squirrel could still be dinner.
-Sasha Rogers

At 7:03 PM, Anonymous Anonymous said...

Because squirrels uses snake odor, do other animals that prey on snakes with their scent also prey on the squirrels?

- David Huynh

At 7:34 PM, Anonymous Anonymous said...

I think this is very interesting because I would never have guessed animals, especially squirrels, use methods like this to avoid predators. I wonder if other snakes can smell the scent of the rattlesnake on the squirrel and also stay away or if only the rattlesnake sense this. Do male squirrels ever do this or only females protecting their young?

-Julie Riley

At 7:50 PM, Blogger PWH said...

Thats a strange method. It's funny that squirrels do that, I would have never guessed. Is it only in certain parts of the country where snakes are more common that they have evolved this behavior? Or is this something that even squirrels around here do? If so, I certainly have never witnessed it.

Ashley Maillet

At 8:10 PM, Blogger PWH said...

I know that scent is indeed a major component used in species recognition. I wonder if this technique adopted by the squirrels is only useful because the rattlesnake's radar is limited mostly by heat and scent detection. Do you know which technique is the most effective for the squirrel?

-Helen Thi

At 8:59 PM, Blogger PWH said...

I wonder about the spreading the snake skin on their bodies, how long does it last? and does this attract the snakes predators to the squirrels?

Jennifer Smith(8)

At 10:24 PM, Blogger PWH said...

Does the scent of the snake mask the scent of the squirrel? Or, is it that the snake is repelled by the smell of another snake?

Jimmy Sullivan

At 11:14 PM, Anonymous Anonymous said...

That is so interesting! So what about animals that prey on snakes- do they go after squirrels at all because of the snake scent? Also why do only females and young do this? Finally, how do you think these squirrels learned how to do this?

-Alyson Paige

At 12:07 AM, Blogger PWH said...

strange, I always thought that snakes typically used heat detection through sensory pits lining their law lines in order to properly detect their prey and not olfactory methods. I am curious as to the effectiveness of this method, has it been tested in a lobratory setting? Does this method work when sqirrels are dealing with other ratllesnakes such as Timber rattlesnakes? native to our area

-Joe Alonzo

At 1:27 AM, Blogger PWH said...

does the article mention how effective the method is and by how much it increases the survival of the squirrels?

Hessom Minaei

At 1:47 AM, Anonymous Anonymous said...

So just to make this clear...the squirrels find rattlesnake skin lying around and smear it on themselves so they wont be attacked? Is this rare?? because it doesn't seem like there would be tons of rattlesnake skin lying around... Does this work with any snake or only rattlesnake? And do all snakes use the sense of smell to find their prey or only rattlesnake?

Brena Sena

At 1:59 AM, Anonymous Anonymous said...

Wow, this is really cool. It is very interesting that the squirrels will use snake-skins to camouflage there scent this way. I am curious to see if this will have any affect on animals other than the snakes. Will their new smell scare off other squirrels or other animals which are prey to the snakes?

Alex Jackson


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