{"id":793406,"date":"2026-10-06T05:38:15","date_gmt":"2026-10-06T05:38:15","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/793406\/"},"modified":"2026-10-06T05:38:15","modified_gmt":"2026-10-06T05:38:15","slug":"yosemite-toads-are-entering-their-winter-burrows-healthy-and-emerging-in-spring-with-deadly-infections","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/793406\/","title":{"rendered":"Yosemite toads are entering their winter burrows healthy \u2013 and emerging in spring with deadly infections"},"content":{"rendered":"

A deadly fungus known as\u00a0Batrachochytrium dendrobatidis\u00a0(Bd) is\u00a0devastating\u00a0amphibian populations around the world. Now, biologists from the University of California, Los Angeles (UCLA) believe one of these threatened amphibian species \u2013 the Yosemite toad \u2013\u00a0may be infected by the fungus\u00a0in a previously unknown way: through its burrows.<\/p>\n

The finding,\u00a0published in\u00a0Functional Ecology<\/a>,\u00a0is being used to inform a captive rearing and reintroduction programme to protect the species.<\/p>\n

The Yosemite toad (Anaxyrus canorus) lives almost exclusively in Yosemite and Sequoia and Kings Canyon national parks in\u00a0central California, USA. It was listed as threatened under the Endangered Species Act in 2014 and is a species of special concern in California.<\/p>\n

Measuring between 2.5cm and 7.5cm long, the toads are relatively small and spend large periods of their lives hiding from predators in old rodent burrows. They also use these hideouts for hibernation<\/a> to survive the High Sierra\u2019s harsh winters.<\/p>\n

The toads leave the safety of the burrows to breed in small pools. It\u2019s long been thought that the\u00a0Bd\u00a0fungus<\/a> infects the animals through their skin when they are in these bodies of water. But the new study reveals an alternative source of infection.<\/p>\n

\"YosemiteYosemite toads breed in small ponds but spend much of their time underground. Credit: gribben\/Getty Images<\/p>\n

Researchers from UCLA and Yosemite National Park assessed Bd prevalence and severity in Yosemite toads before and after winter dormancy, concluding that previously healthy toads emerged from their winter burrows heavily infected.<\/p>\n

According to UCLA ecologist Dave Daversa, who led the study, this suggests that the fungus may proliferate underground in winter. \u201cThe results of our\u00a0Bd\u00a0surveillance study of Yosemite toads were completely unexpected,\u201d says Daversa. \u201cAlthough\u00a0Bd\u00a0is a largely aquatic pathogen, we discovered that major outbreaks of infection grow and spread during winter hibernation on land.\u00a0<\/p>\n

\u201cThe discovery sharply contrasts with current thinking about the high-risk season for\u00a0Bd\u00a0infection, which has often been assumed to occur when amphibians are breeding in water. Our study flies in the face of that expectation.\u201d<\/p>\n

The new findings also suggest that Bd can thrive during harsh winters \u2013 this contradicts the previous line of thought that the fungus grows best in more moderate conditions.<\/p>\n

\"YosemiteA Yosemite toad in the Sierra Nevada mountains, California. Credit: gribben\/Getty Images<\/p>\n

The authors note that they don\u2019t know for sure that the toads are picking up new infections in the burrows. Another theory is that they may carry light, undetectable infections into their underground lairs \u2013 with the infection intensifying over time.<\/p>\n

\u201cHow pathogens persist in host populations with incredibly seasonal life histories is one of the puzzles we study,\u201d says co-author Jamie Lloyd-Smith, a UCLA wildlife disease ecologist.<\/p>\n

\u201cThis fungus isn\u2019t supposed to grow happily at such low temperatures \u2013 either the temperatures above ground or the temperatures we suspect exist in the burrows. We speculate there might be something going on with the immune system \u2013 the immune state of the animal might be going down even lower than the ability of the fungus to grow.\u201d<\/p>\n

Perhaps the most notable takeaway from a conservation perspective is that young toads or those in the metamorphic stage of their life cycle are far more at risk of infection than fully mature animals. As a result of this finding, captive-reared animals are now only released after a few years of growth, when they are at less risk of overwinter\u00a0Bd\u00a0infection. \u00a0<\/p>\n

Find out more about the study, published in\u00a0Functional Ecology<\/a>.<\/p>\n

More wildlife stories from around the world<\/p>\n

Top image: Dana Fork, Yosemite National Park, close to where the study was carried out. Credit: Different_Brian\/Getty Images<\/p>\n","protected":false},"excerpt":{"rendered":"A deadly fungus known as\u00a0Batrachochytrium dendrobatidis\u00a0(Bd) is\u00a0devastating\u00a0amphibian populations around the world. Now, biologists from the University of California,…\n","protected":false},"author":2,"featured_media":793407,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[90,56,54,55,4407],"class_list":["post-793406","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-science","tag-uk","tag-united-kingdom","tag-unitedkingdom","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/793406","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=793406"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/793406\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/793407"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=793406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=793406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=793406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}