{"id":260520,"date":"2026-01-31T05:31:13","date_gmt":"2026-01-31T05:31:13","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/260520\/"},"modified":"2026-01-31T05:31:13","modified_gmt":"2026-01-31T05:31:13","slug":"inbreeding-threatens-michigans-only-rattlesnake-what-it-means-for-conservation","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/260520\/","title":{"rendered":"Inbreeding Threatens Michigan\u2019s Only Rattlesnake \u2014 What It Means for Conservation"},"content":{"rendered":"

The post Inbreeding Threatens Michigan\u2019s Only Rattlesnake \u2014 What It Means for Conservation<\/a> appeared first on A-Z Animals<\/a>.<\/p>\n

Quick Take<\/p>\n

Michigan\u2018s only rattlesnake species, the eastern massasauga, shows evidence of inbreeding depression.<\/p>\n

More inbred individuals in two populations of eastern massasaugas have lower reproductive output and survival.<\/p>\n

Measures to restore genetic fitness to these populations may be needed to prevent local extinctions.<\/p>\n

Maintaining habitat corridors for dispersal could benefit other snake species that may also be susceptible to inbreeding depression.<\/p>\n

If you come across a rattlesnake in Michigan, it\u2019s an eastern massasauga (Sistrurus catenatus), the only venomous snake in the state. They\u2019re relatively small for rattlers, averaging two to three feet long as adults. You\u2019d be lucky to spot one, since eastern massasaugas spend most of their time hidden under logs or brush near wetland habitats and tend to flee when disturbed. So, although massasaugas have a venomous bite, people are rarely bitten.<\/p>\n

While they have a geographically wide range across multiple U.S. states from Michigan to Missouri, populations of eastern massasaugas have declined precipitously since the mid-1970s, according to monitoring by the U.S. Fish and Wildlife Service. They were listed as threatened<\/a> under the Endangered Species Act in 2016, with the causes of their decline considered illegal collection and fragmentation of their habitats over the past 200 years.<\/p>\n

\"<p>Barriers<\/p>\n

Barriers imposed by roads, buildings, and farms limit the movements of wildlife, including massasaugas.<\/p>\n

\u00a9Dwight Burdette \/ CC BY 3.0 \u2013 Original<\/a> \/ License<\/a><\/p>\n

(Dwight Burdette \/ CC BY 3.0)<\/p>\n

As development of roads and human settlements has proceeded, eastern massasaugas have become confined to increasingly smaller patches of habitat. In a recent paper<\/a>, conservation biologists found that habitat fragmentation is making it difficult for massasaugas to reproduce successfully and, therefore, reducing their chance of survival into the future.<\/p>\n

Biologists from Michigan State University used genetics to trace the family histories of snakes in two populations. By partnering with long-term monitoring projects run by Grand Valley State University, West Virginia University, and the Association of Zoos and Aquariums, the researchers were able to gain DNA samples from more than 1,000 individual snakes that had been captured and released in a project funded by the U.S. Fish and Wildlife Service.<\/p>\n

Each captured snake was weighed, measured, assessed for sex and reproductive status, sampled for blood, and then released with a unique PIT tag for individual recognition. DNA from the blood sample served to construct family trees for the populations, showing the relatedness between individuals. Over 15 years, visits to the two populations yielded estimates of snake births and snake deaths.<\/p>\n

\u201cThis long-term field monitoring is the backbone of the study,\u201d said lead author, then graduate student, Meaghan Clark, in a press release<\/a>. \u201cHaving people out each season catching these snakes made all of this possible.\u201d<\/p>\n

\"speckled<\/p>\n

Because they\u2019re venomous, massasaugas are handled in clear acrylic tubes during measurements.<\/p>\n

\u00a9Nathan Rathbun\/USFWS\/public domain \u2013 Original<\/a> \/ License<\/a><\/p>\n

(Nathan Rathbun\/USFWS\/public domain)<\/p>\n

The data analysis showed that massasauga inbreeding in these two populations is resulting in reproductive problems. By mating nonrandomly with more closely related snakes, these massasaugas reduced their chance of producing viable offspring. Inbreeding reduces fitness by amplifying the expression of harmful combinations of genes. The most inbred massasaugas were 3.5 percent less likely to have surviving offspring and had an 11.6 percent lower annual survival rate themselves. But why would these eastern massasaugas choose to mate with their relatives?<\/p>\n

\u201cHabitat loss and fragmentation prevent occasional migration between eastern\u00a0massasauga\u00a0populations, which over time increases the relatedness within each population,\u201d lead author Clark explains via email. Additionally, massasaugas naturally tend to disperse short distances from their parents, limiting gene flow away from their natal populations. \u201cIn our dataset, we found that the distance between snakes and their parents was less than the distance between pairs of unrelated individuals,\u201d Clark adds.<\/p>\n

So, the Michigan massasaugas, already homebodies, are being further squeezed into proximity with their relatives by the alteration and loss of habitat. Genetic relatedness of parents causes \u201cinbreeding depression\u201d\u2014known decreases in fitness and survival. Over time, you\u2019d expect inbreeding depression to reduce Michigan massasauga population sizes, leading to more breeding with close relatives in a vicious cycle.<\/p>\n

Other eastern massasauga populations are often even smaller, and their movements are similarly restricted by roads, farms, and other barriers. This was the first study to directly quantify the impact of inbreeding, resulting from habitat fragmentation, on the fitness of eastern massasaugas.<\/p>\n

\u201cThese are fairly large and stable populations of Eastern Massasaugas,\u201d said senior author Sarah Fitzpatrick in a press release<\/a>. \u201cThe fact that we\u2019re detecting problems from inbreeding in these populations is concerning, given that many other populations throughout the Midwest are much smaller and even more fragmented.\u201d<\/p>\n

Once a population of organisms becomes small and isolated, its chance of going locally extinct rises dramatically. A single natural event could wipe out these massasauga populations, which lack the buffer of a nearby feeder population to replenish both genetic diversity and individuals.<\/p>\n

\"snake<\/p>\n

More continuous wetland habitat could help safeguard Michigan populations of massasaugas.<\/p>\n

\u00a9Abbey Kucera\/USFWS Midwest Region\/public domain \u2013 Original<\/a> \/ License<\/a><\/p>\n

(Abbey Kucera\/USFWS Midwest Region\/public domain)<\/p>\n

Clark says, \u201cThe way to counter this decline is to increase population size and facilitate gene flow with other populations [of massasaugas]. There\u2019s currently research underway as to how to best do this.\u201d Rescuing genetic diversity to limit deleterious gene combinations may be key to protecting the Michigan populations of eastern massasaugas and may even warrant moving snakes from other populations.<\/p>\n

The study authors also recommend long-term monitoring of other snake populations to figure out whether they\u2019re successfully maintaining their gene pools in the face of environmental changes that limit habitat connectivity. Implementing changes such as building underpasses for snakes to cross roads or creating openings in fences could improve connectivity and, therefore, increase gene flow between populations.<\/p>\n

The post Inbreeding Threatens Michigan\u2019s Only Rattlesnake \u2014 What It Means for Conservation<\/a> appeared first on A-Z Animals<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"The post Inbreeding Threatens Michigan\u2019s Only Rattlesnake \u2014 What It Means for Conservation appeared first on A-Z Animals.…\n","protected":false},"author":2,"featured_media":260521,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[149549,42332,149548,149550,2145,81738,111,139,69,147,45239,406],"class_list":{"0":"post-260520","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-eastern-massasauga","9":"tag-fragmentation","10":"tag-inbreeding-depression","11":"tag-massasaugas","12":"tag-michigan","13":"tag-michigan-state-university","14":"tag-new-zealand","15":"tag-newzealand","16":"tag-nz","17":"tag-science","18":"tag-venomous-snake","19":"tag-wildlife"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/260520","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=260520"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/260520\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/260521"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=260520"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=260520"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=260520"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}