The autumnal equinox, or the first day of fall, is today! It’s a time when birds have already begun their gradual migrations to southerly, warmer lands, and our black bear is undergoing hyperphagia, a process of eating as much as possible to build fat reserves for winter survival. One has to wonder if the fall season affects other organisms, such as rattlesnakes, in any similar way.
We know that in August, some rattlesnakes begin producing babies and also breeding in order to set up baby production for the next August. With this process overlapping into September, those snakes not involved with reproduction, like females that have already given birth and other non-breeding females, and males not breeding this year, will begin to step up their fall season food search in order to increase fat stores in advance of winter. The fall season feeding binge is also necessary to ensure future baby production, occurring every year and a half to two years. This feeding process helps all rattlesnakes get through winter hibernation underground by maintaining body health, and while the focus on feeding goes on, rattlesnakes are also gradually moving to denning locations in which hibernation takes place, locations sometimes used every winter. They must be in place to hibernate by early November to avoid freezing.
Fall is a busy time for all snake species, even those which produce babies in the spring ahead of the rattlesnake’s schedule. The earlier breeding and reproduction still means that the fall season drives snakes to feed well and gradually begin to orient their movements to areas where hibernation takes place, just like the rattlesnakes do.
Since snakes are active during the fall season, be sure to check out our snake safety tips guide.
Written by Bryon Shipley
Prairie Rattlesnake, Adaptation
It’s winter and this finds us writing about amphibians and reptiles rather than surveying them in the field.
(Well, that’s not totally true as it’s not winter in the Peruvian Amazon (near Iquitos) where our Venomous Safety Instructor, Matt Cage, is guiding amphibian and reptile enthusiasts and photographers through the jungle.)
Here’s a special find he recently shared:
Langsdorff’s Coralsnake, Micrurus langsdorffi, photo by Matt Cage
Back in North America it is winter, and except for a few warmer spots deep in the southern U.S. our amphibians and reptiles remain hunkered-down a little bit longer before their seasonal activity begins.
However, the deep south (Florida, I’m talking about you) recently did get hit with a cold snap causing iguanas (Spiny-tailed species, Ctenosaura sp., and Green Iguanas, Iguana iguana) to start falling from trees. Iguanas are not native to Florida and thus cold temperatures potentially pose a bigger problem for this species over native ones. Chilly lizards have difficulty escaping predators, and so our native lizards adapt to this lack of heat by overwintering underground and typically below an area subjected to freezing temperatures. Iguanas are not exactly welcome in Florida and cooler temperatures certainly provide opportunities to capture them more easily, potentially helping native wildlife populations by reducing the nonnative competitor of local resources.
Iguanas are not cold-tolerant, and this restricts their nonnative populations from expanding. Some nonnative species are more tolerant of cooler temperatures and their populations may expand more easily. For instance, in 2005-6 my collaborators and I studied Cuban Brown Anoles (Anolis sagrei) to evaluate their tolerance to cold in populations from south and central Florida and into Georgia. Individual Cuban Brown Anoles with an ability to tolerate cold were able to find areas to persist. Although this small lizard competes with our native Green Anole (Anolis carolinensis), it’s generally not considered a problem for people.
But what happens when a not-so-small lizard figures out a way to survive the cold? This is currently a growing problem in the southeast with Argentine Black-and-White Tegus (Salvator merianae). These lizards compete for burrows in the winter, eat native species (both common and imperiled species), and may negatively impact our own pets and gardens. Control programs are in place, but eradication may be unlikely at this point.
Adaptation’s team continues to study wildlife and plant species whether they’re native to certain areas or not. Although species populations naturally shift, our work with agencies better helps our collective understanding of these shifts and species-specific needs. This work helps track non-native species movements to determine how problematic this could be and if control methods are an option.
Do you want to help? Maybe you’re not comfortable with identifying wildlife and/ or plants…no worries. Next time you’re outside, notice that cool bug, bird, or flower and share your observation. One way to do this, is through the iNaturalist application. Recording your observations here will get reported to agencies managing our resources for us all.
Happy Snake Season 2020!!
Adaptation Environmental Team: Bryon, Joe, and Kelly