An Oddball Massasauga

After a considerable stretch of warm weather in the past week or two in Michigan, temperatures have finally dropped to their norms for this time of the year. The weather was warm and sunny last weekend and so I decided to take a trip out to a new area with Chris Boguslawski to scout some massasauga habitat on state land. The more time I've spent in the field with massasaugas, the more I've learned how diverse their habitat in Michigan can be. I've found them in open canopy wetlands such as prairie fens and wet meadows, lake edges, tamarack swamps, and even in woodlands.

The tamarack swamps and floodplain forests which line this river are ideal habitat for Michigan's only venomous species of snake. We decided to walk some of these areas on Sunday afternoon, the sun was shining and temps were hovering in the low 60s. The thick underbrush in this habitat made navigating through it a bit difficult, but I was optimistic about our chances of seeing a rattlesnake out basking. Within a few short minutes, I came across this hefty adult trying to soak up some late October sun.

Eastern Massasauga Rattlesnake - Sistrurus catenatus catenatus

This snake showed clear signs of having spent time in a crayfish burrow, but was still sharp. But upon further investigation, the snake appeared to have a large, bulbous sore on its neck the size of a half dollar.

I've seen photos of others snakes with large sores like this, sometimes they can be sores from below breezing temperatures and other times it can just be an injury in the process of healing. There are other concerns with this type of abscess, one of Illinois' only viable populations had recently been hit by a fungal infection which has been fatal to several snakes, usually due large tumors on the head and neck. You can read about that issue here; Fungal Infection Poses a New Threat to the Eastern Massasauga. Nonetheless, it was great to find a massasauga at a new site so late in the season. But it will be something to keep an eye on with this population in the future.

Fungal Infection Poses a New Threat to the Eastern Massasauga

There's plenty of attributing factors as to why the Eastern Massasauga has declined across its range. However, a new threat has emerged in at least one population that has caused a lot of concern among biologists and conservationists alike. A fungus known as Chrysosporium has caused the death of at least three rattlesnakes in an isolated Illinois population, which you can read about here via the University of Illinois. The infected snakes exhibited grotesque facial disfigurations and lesions due to infection by the fungus and eventually died due to complications from the infection.

Chrysosporium is a prevalent infection within the pet trade and is a common infection that effects lizards, snakes, and sometimes humans. However, this is the first time that an infection from the fungus has been documented in a population of free ranging snakes. But similarly infections have been documented in Timber Rattlesnakes in the northeastern United States. It is concerning that this pathogen has emerged in snakes as different type of fungus like chytrid fungus have caused massive population declines in amphibians.

However, at the end of the day is unclear as to what the emergence of this infection has in store for other Massasauga populations. The affected population is extremely small and isolated and suffers from a high frequency of inbreeding events. It's possible that this population was more susceptible to infectious disease because of immunosupression due to poor genetic diversity and healthier populations may have nothing to worry about for the time being. But in any case further research is needed to better understand this pathogen and its effect on snake populations, including the Eastern Massasauga.