Tuesday, April 17, 2012

Snake-snake Interactions: do they have meaning?

When multiple species of snake live in the same habitat, how do they interact? Do they communicate with each other? At the Blue Oak Ranch Reserve where human presence is greatly reduced, snake diversity is high and many species occur at high population densities (see species accounts one and two). Our cameras have captured a few rattlesnakes investigating other species of snake. On June 22, Mace Windu, a male Northern Pacific rattlesnake interacted with a king snake and a gopher snake (at separate times). Below are recordings of these interactions (you may want to watch on YouTube to view better video quality). 

A king snake bumps into Mace while slithering through the grass. Mace is sitting in ambush in the shadow as the king snake moves through the grass. The king snake retracts its head after it realizes that a rattlesnake is there. It quickly flees and Mace extends his head, as if curious.  

A couple of hours later, a gopher snake runs into Mace. The camera is not directly pointed at Mace, but he is partially visible resting in the shade of a rock. A gopher snake moves toward Mace and stops once it realizes that a rattlesnake is there. It quickly takes off, and Mace extends his head and body toward the gopher snake. Is Mace just curious or is he communicating with the gopher snake?

These recordings make me curious about snake-snake interactions: 
How often do different species of snake interact, and when they do, what are the nature of these interactions?
Can different species of snake communicate with each other? 
King snakes are predators of young rattlesnakes, but how do they interact with adults like Mace? 

At BORR, many species of snake live in the same habitat and must interact in some way. Our cameras have been catching glimpses of these interesting snake-snake interactions so hopefully with more video footage we can learn more about them!

Friday, April 13, 2012

Best News Article Yet!

Over the past couple of weeks our research has been featured in several news articles (Time, MSNBCHuffington Post, Fox News), but the article in the San Jose Mercury News is by far the most informative and scientifically accurate. The reporters came out with me last Monday as I searched for snakes for the up-coming field season. They were very excited to learn more about rattlesnakes and the research that is being performed in their own backyard. Check it out!

Wednesday, April 4, 2012

Strike and a Miss

Below is an awesome screenshot from one of our field recordings. In it, Greeata, a female rattlesnake strikes at an adult squirrel that has been harassing her for the past two minutes. The blue arrow is pointed at Greeata's open mouth as she lunges her head out of the log. The orange arrow is pointed at the squirrel's head as it dodges the snake strike. 

This screenshot is intriguing because we rarely observe strikes on squirrels that are actively harassing snakes. This is because squirrels are more likely to evade a strike when they are aware of the snake's presence and snakes don't want to waste time and energy on a strike that will be unsuccessful.  This poses the question, why did Greeata strike at this squirrel? Was it a defensive strike rather than a predatory strike? She should have known her strike would be a miss and saved it for another day. One aspect of rattlesnake behavior that I am particularly interested in is the inter-individual variation in strike reactivity. There may be a continuum of behavioral types where some individuals are more judicious, strike less often, but have better strike accuracy while others are more reactive, strike more often, but have less strike accuracy. I hope to capture more snake strikes to analyze this fascinating aspect of rattlesnake hunting behavior.