Plants and Animals
Missouri’s largest venomous snake has the camouflage and demeanor to keep it under the radar.
“Be careful where you step,” instructed Lia Heppermann as the radio tracking device on her belt chirped at its highest frequency yet. We came to a stop and scanned the area to no avail until Heppermann finally whispered, “It is right between us.” I slowly looked downward in the dim light of dusk and saw the beautiful reptile, a master of camouflage, coiled at our feet—a timber rattlesnake.
Earlier in the week, Heppermann, a wildlife biologist with the Missouri Department of Conservation, had been monitoring the movements and habitat use of resident timber rattlesnakes (Crotalus horridus). Aware of my love for nature photography, she asked me if I would like to come along and photograph one of her “subjects.” Heppermann was participating in a cooperative study between the Department of Conservation and the St. Louis Zoo. I jumped at the opportunity, as I’d never seen a rattlesnake in Missouri, and I certainly never expected to photograph one.
Timber rattlesnakes are Missouri’s largest venomous snake, growing to a length of 3 to 5 feet. Like all venomous snakes in Missouri, the timber rattlesnake is a pit viper, which means that it has a temperature-sensitive hole between the nostril and the eye that it uses to detect warm-blooded prey. Other characteristics of the timber rattlesnake include its tan color, rustcolored stripe along its back overlain by dark blotches, vertical pupils and a rattle at the end of its tail. Timber rattlesnakes also have a dark line extending from each eye along the angle of their jaw.
According to the Department of Conservation book, Snakes of Missouri, timber rattlesnakes can be found on rocky wooded hillsides, especially southfacing slopes, where they take advantage of the sun’s warmth throughout the day, especially during cooler months. During the summer, they find a cool place to rest during the day and limit their activity to evening hours. Timber rattlesnakes are in decline in Missouri, mostly due to degradation of habitat and persecution by humans.
Timber rattlesnakes are active from April to October and breed soon after they emerge from overwintering dens. Females give birth every other year to eight or nine self-sufficient young in late summer. Timber rattlesnakes feed on a variety of rodents and the occasional cottontail by striking and injecting venom to subdue their prey. A secondary use of venom is for self-defense, but bites from the timber rattlesnake are extremely rare in Missouri. As a matter of fact, they rarely show aggression, even in close proximity to humans or other large animals that are not considered as prey.
“I would love to get a shot at eye level,” I urged Heppermann after she recorded the GPS coordinates of the coiled creature. Because the snake was situated on a slope, I was able to obtain a low angle shot by crouching at a safe distance, producing a face-to-face image of the docile animal; a female, according to Heppermann. As we departed the forest at dusk, I reveled in my experience and felt invigorated to have participated, if even for a day, in a study that would help to ensure a prosperous future for this regal reptile.
story and photo by Danny Brown