San Diego RattlesnakeAs a San Diego resident, I can agree completely with all of my clients when they say how much they love living in this community. Many speak highly of the shopping and dining as well as being able to walk to their children’s baseball or soccer games and of course the wonderful trails here to explore with our dogs. Unfortunately, those same trails are home to critters we may not be so fond of including Rattlesnakes and Coyotes.

San Diego is home to 3 of the 32 different species of Rattlesnakes including: the Southern Pacific Rattlesnake (pictured above, which is quick to react/display/strike), the Southwestern Speckled Rattlesnake (which is extremely rare and prefers to live in rocky hillsides away from humans) and the most commonly seen Red Diamond Rattlesnake (pictured below, which is generally quite placid, rarely choosing to display). Learning more about rattlesnakes and their natural behavior can help you remain safe if you do encounter one on your walks or in your own backyard.

When we compare our 5 senses to a rattlesnake’s we find that rattlesnakes have a couple of extra senses to aid in their survival. They do not have any external ear flaps and they do not hear like we do. Instead they hear or sense vibrations, especially lower vibrations and the “sounds” are transmitted to their auditory nerve for processing those vibrations. In their eyes, they have a higher amount of rod cells than we do, permitting them to see better in lower light. They also have some cones suggesting that they may be able to detect colors. They do not have moveable eyelids which can pose a problem for them if they are not careful when they are striking an animal that may fight back. Our eyes have muscles that change the shape of our lenses when we focus on an object. The lenses of rattlesnakes act more like a camera lens, moving in and out to focus on the object. They do not have a fovea or focal point like we to so their visual acuity is not as defined or sharp as ours. Rattlesnakes behave as if they see shapes, sizes, lights, shadows and movements. They do have olfactory cells so they can detect faint odors; including prey, potential mates and predators (King Snakes eat rattlesnakes). San Diego Rattlesnake
Their skin is amazingly sensitive especially to temperature changes and they are most active when the weather is between 80 – 90 degrees. The last of our senses, taste, is where the rattlesnakes get interesting. They do not have any taste buds, but they possess two other features that are quite intriguing. Rattlesnakes are referred to as Pit Vipers because they have facial pits that are located between the nostril and the eye on each side of their head. These pits contain nerve endings that sense heat radiation enabling them to detect warm blooded animals. They move their head from side to side to hone in on the infrared information to help them detect potential prey. They also have a chemoreceptive organ called the Jacobson’s Organ that would be considered a combination of taste and smell in other animals. Their forked tongues dart in and out of their mouth transmitting all of the information gathered from microscopic particles in the air.

Snakes are cold blooded which means that they do not need to eat daily to maintain their body temperatures and bodily functions. Instead they rely on the heat of sun and therefore only have to eat about 3 X their body weight annually. They feed mostly on small rodents, but they can also eat insects, lizards, frogs, bird eggs and occasionally other smaller snakes. They tend to eat their prey head first use one of two tactics for acquiring their prey. They will bite and hold onto the prey until the venom takes effect or strike and release the prey following after it to eat it when the venom takes effect. They eat their prey whole using 4 rows of single teeth along both sides of their jaw to move the prey along. Their fangs are shed about every 6 -10 weeks but only one at a time so that they always have at least one fang ready to strike with. Snakes do drink water especially during the time around the shedding process. Approximately 10 days before shedding occurs, liquid builds up between the old and new skin and clouds the eyes, impairing their vision greatly forcing them to go into hiding for safety.
San Diego RattlesnakeMating occurs shortly after the females shed and if you are very lucky, you may get to witness the “Combat Dancing” which is a display of strength between competing males. The females do not eat during their 3 month gestation and can lose up to 50% of their body weight before they give birth to a litter of 6 -10 snakes that are miniature versions of their parents ready to face the world immediately. A female may hang around the den for a few days but there is no actual parental care.

Internally, they have 160 – 400 pairs of ribs (humans have 12 pairs) and there is no sternum. They move in an undulating fashion and can swim quite well. They have a 3 chambered heart (humans have a 4 chambered heart) and although they do have 2 lungs, only their right lung is actually functional. Their rattle is made up of keratin (like our fingernails) and each molt or shed produces a new segment on the rattle. If you are thinking that you can age a rattlesnake by counting the segments, you would be mistaken as they can shed 2 – 3 X a year and sometimes the segments break off. When a snake reaches maturity, the segments are closer in size in relation to the each other without any tapering and there may be 8-10 segments. Their skin coloration or camouflage is called cryptic coloration as opposed to counter shading for dolphins or disruptive coloration for killer whales.

What to know about living with and hiking around rattle snakes:

  • Learn how to recognize rattlesnakes – gopher snakes sometimes coil up, hiss and vibrate their tail to imitate a rattler.
  • Rattle snakes have thick bodies, triangular shaped head, a distinct “neck”, openings (Pits) between nostrils and eyes, hooded eyes, and the Red Diamond Rattlesnakes have a series of light and dark bands near the tail just before the rattles.
  • Rattlesnakes are mostly active at twilight and after dark and prefer temperatures between 80 – 90 degrees.
  • Never go barefoot or wear sandals while hiking or walking on our trails.
  • Avoid tall grasses and heavy underbrush where snakes may be hiding during the day – stay on the trails and keep your dogs on their leashes.
  • Step on logs and rocks not over them (snakes may be on the other side).
  • Avoid wood piles and use gloves whenever possible when climbing around downed trees, boulders and shrubbery close to the ground.
  • Do not handle a freshly killed rattlesnake as it can still inject venom.
  • DO NOT handle live snakes (most snake bites occur while being handled, moved) try to drop a trash can over it, place a brick or rock on top of the can and call animal control.
  • Snake proof your yard with a snake fence that is a tight chicken wire with mesh no larger than ¼ inch, 3 feet high and buried a few inches into the ground, slanting the fence about 30 degrees outward may help to keep the snakes out as well. Clear away vegetation and wood plies (good idea for fire protection as well).
  • Research products like Bonide Snake Stopper – Snake Repellent which you sprinkle around the outside of your property fence line.
  • Research snake vaccines for your dog – although it is not a complete vaccine that protects your dog, it may provide you a little extra time to ensure you can get to a vet for treatment.
  • Know the contact info for your vet as well as the emergency vet hospital and CALL AHEAD to make sure that the vet hospital has the anti venom available and to give them a heads up that you are coming with your dog (provide name, age, breed, size, weight of your dog).
  • Animal Urgent Care of Escondido (760) 738-9600 2430 S Escondido Blvd.


  • Try to keep calm
  • Wash bite area with soap and water
  • Immediately remove watches or rings
  • Immobilize area
  • Even though 25% – 50% of bites are “dry” you should ALWAYS seek medical attn