Snakes Are Clumsy, Just Like Us!

Like all animals, snakes are not perfect. They make mistakes and sometimes misjudge their abilities. Even though you would assume snakes would be clumsy all the time because they are limbless, they normally are quite graceful. They have extremely well-developed musculature and scales that allow them to move in various ways. In fact, they can do almost anything a four-limbed animal can do, using only their tube-shaped body. 

For instance, they can climb trees, 

 hold their food in place while eating,

and even soar through the air.

However, every once in a while, they mess up. After many years of watching snakes in the wild, I've seen some pretty funny snake mistakes. Here are a few of my stories from the field:

1) If you've ever hiked the California foothills in late summer, you may have accidentally fallen down a steep hill from trying to walk on extremely slippery dried out grass. Well, I've also seen a snake make this same mistake - accidentally sliding all the way down a dry grassy hill it was trying to traverse. Poor little girl was dazed and confused after her clumsy fall.

2) Snakes eat pretty big meals which sometimes make it hard for them to move. This past summer we recorded a snake trying to relocate sites after having consumed an adult ground squirrel. This squirrel was roughly half the total body mass of the snake - that's one BIG meal. After consuming the squirrel, the snake attempted to exit a log, but got stuck in the exit hole by his huge food bulge. After a couple seconds of trying to squeeze through, he finally realized that he needed a new exit strategy. Check out the video of his snake mistake below!

3) A couple years back, we captured footage of a snake making a huge mistake while attempting to strike a ground squirrel pup. This snake lunged forward during the attack, but missed the pup, and instead fell down a hill. Needless to say, we felt bad for the poor guy. He lost a tasty meal and got injured in the process. Check out the video on our lab channel below!

http://www.youtube.com/watch?v=dJ0EmVnDHkE

This post just goes to show you that we are all subject to error, and that we should take our mistakes with stride! What are some animal mistakes you've seen? 

BTW, Dan Deacon is a great artist who encourages audience participation at his shows and he also has a song called Snake Mistakes. Check it out here.

Happy early Thanksgiving to you all!

Disguised as the Enemy: Squirrels Use Snake Sheds to Mask their Scent

I passed my Ph.D. qualifying exam last Friday and I'm so glad that it's over! Please enjoy this fun little blog post I wrote to celebrate my advancement to candidacy. 

Several studies have shown that ground squirrels lick their fur after chewing shed rattlesnake skin. Many other animals have been shown to exhibit similar scent application behaviors (Table 1, Clucas et al. 2008b). Such behaviors are thought to transfer odiferous chemicals that repel potential parasites or predators onto the fur of the animal. Smelly fur may also affect the behavior of individuals of the same species (in social situations).  

The ground squirrels’ behavior of chewing snake sheds most likely masks their squirrelly odor from snake predators. Rattlesnakes have been shown to be more attracted the ground squirrel scent alone compared to ground squirrel scent mixed with rattlesnake scent (Clucas et al. 2008a). This supports the hypothesis that squirrels apply snake scent onto themselves to reduce the risk of rattlesnake predation. It’s a cool behavior that is often talked about, but rarely seen.

When shedding, snakes usually remain protected in their burrows. This is because the skin layer thickens over their eyes decreasing their ability to see and making them vulnerable to predation. Can you see how cloudy this snake's eyes are? He is just about to shed!

One morning this past summer, we came across a beautiful rattlesnake shed skin while radio-tracking Quirky Quinton (male northern Pacific rattlesnake). Quinton had literally just emerged from this shed; his body shape was beautifully preserved in it, and his scales were shiny and new. We took his shed with us to our field station camp and laid it out in the dirt. In no time, a squirrel pup emerged and starting performing the snake scent application behavior! This was very exciting for us because this behavior is rarely seen. We suspect that this is because squirrels prefer fresh sheds over old ones. Luckily our fresh shed induced this behavior and we recorded footage of it. Please enjoy watching the video of this rarely seen unique antipredator behavior.

References:

Clucas, B., D. H. Owings, and M. P. Rowe. 2008a. Donning your enemy’s cloak: ground squirrels exploit rattlesnake scent to reduce predation risk. Proceedings: Biological Sciences 275:847–52.

Clucas, B., M. P. Rowe, D. H. Owings, and P. C. Arrowood. 2008b. Snake scent application in ground squirrels, Spermophilus spp.: a novel form of antipredator behaviour? Animal Behaviour 75:299–307.

Do Snakes Stress Out Squirrels?: Guest Post by Lauren Kong

Lauren is a graduate of Mills College where she was a Barrett Scholar last year. Her scholarship through the Barrett Research Program funded her stay with us at the Blue Oak Ranch Reserve. Her adviser at Mills, Dr. Jennifer Smith, is collaborating with me on a project examining the sub-lethal effects of snakes on ground squirrels. Lauren was in charge of data collection and organization for this project. She describes her research below: 

        

My research question focused on whether California ground squirrels (Otospermophilus beecheyi) were becoming stressed out after interacting with predatory snakes- the northern Pacific rattlesnake (Crotalus oreganus) and the Pacific gopher snake (Pituophis catenifer). To test our hypothesis we staged interactions between snakes and squirrels. We baited focal squirrels near snakes using sunflower seeds (their favorite food). After baiting the area, we waited until our desired ground squirrel approached and interacted with the snake. After the interaction, we trapped the squirrel using humane traps and collected their feces for the rest of the day. As a control treatment, we trapped the squirrel without having it interact with a snake and collected its feces to see if being in a trap affected their stress levels. To analyze the stress levels of squirrels that have and have not interacted with snakes, we will extract stress hormones (glucocorticoids) from their fecal material.

Ground Squirrel Perches on a Rock

It takes approximately 4-6 hours for the glucocorticoids to pass through the digestive system of the squirrel so it’s important to hold the squirrels long enough to get a complete sample. We placed the fecal deposits in tubes on ice or in liquid nitrogen. It’s important to collect the feces as soon as it is expelled because glucocorticoids are subject to degradation once they leave the body. Now that my internship is over, the fecal samples will be transported to the Smith Lab at Mills College for further analysis. We hope to see if venomous, and presumably more dangerous, rattlesnakes induce a greater stress response in squirrels than non-venomous, less dangerous gopher snakes.

 

We placed the squirrels onto plastic trays to collect their feces. Look at how many squirrels we did trials on in one day!

Although behavioral ecology can be taxing, this experience has opened my eyes to field biology. This research would not have been possible without the help of my fellow internists and Bree. Together we are a group of animal loving, enthusiastic, and intelligent people striving to elucidate the mysteries of animal life. This was a truly amazing experience. 

       

Looking over the edge of the Arroyo. Our study site is truly beautiful!

A Tale of Tails

After completing my summer field season on July 20th, I presented data from an experiment at the Animal Behavior Society meeting in Boulder, Colorado. I rushed to analyze the data (which was collected during the 2012 and 2013 field seasons) and create a PowerPoint presentation in less than one week! My goal was to present our "snake cannon" experiment which was designed to test how squirrels respond to simulated snake strikes. We hypothesized that tail-flagging squirrels would respond faster than non-tail-flagging squirrels if tail-flagging truly signals their readiness for a snake strike. Well, I successfully pulled together a beautiful presentation which was a huge hit at the meeting. It was such a success that National Geographic decided to write an article about it on their website. Please read the well-written article, A Tale of Tails, here.