During summer in the Pembina Valley,\u00a0amphibians\u00a0and\u00a0reptiles\u00a0are hard to miss.\u00a0<\/p>\n
From\u00a0choruses of toads\u00a0and\u00a0slithering garter\u00a0snakes to painted turtles lined up on logs\u00a0in the sunlight,\u00a0the animals\u00a0are a fixture of the environment.\u00a0<\/p>\n
In winter, however,\u00a0these sights vanish.\u00a0\u00a0<\/p>\n
While it might seem as though the animals are absent, their lives under the snow and ice rely on overwintering strategies that\u00a0brim with life.\u00a0<\/p>\n
Frogs: Freezing solid\u00a0<\/p>\n
Dr.\u00a0Randy\u00a0Mooi, curator of zoology at the Manitoba Museum,\u00a0said that\u00a0the animal kingdom in winter employs two overarching strategies to combat plunging temperatures: freeze tolerance and freeze avoidance.\u00a0<\/p>\n
For some frogs,\u00a0freeze\u00a0tolerance is key.\u00a0<\/p>\n
As amphibians\u00a0who\u00a0can\u2019t\u00a0create their own heat\u00a0or\u00a0regulate their temperatures like mammals can,\u00a0they\u00a0combat the winter by becoming a part of it\u00a0\u2014 they freeze solid.\u00a0\u00a0<\/p>\n
\u201c[During warmer months], they can change their\u00a0behaviours,\u00a0like\u00a0sitting in the sun …\u00a0to raise their temperature or going into the shade to lower it, but during the winter, they take on the temperature of their environment,\u201d\u00a0explained\u00a0Dr. Mooi.\u00a0<\/p>\n
<\/p>\n
We think things are quiet and dead and that not much is happening, but in the animal world, there are quite a lot of things. Even though\u00a0they’re\u00a0slowing down,\u00a0there’s\u00a0a lot of things happening in their bodies\u00a0\u2014\u00a0and in their\u00a0behaviours\u00a0\u2014\u00a0that are\u00a0pretty important\u00a0for them to survive.<\/p>\n
\n
<\/p>\n
-Dr. Randy Mooi on winter in Manitoba.<\/p>\n
<\/p>\n
Wood frogs, tree frogs, chorus frogs, and peepers\u00a0are some of the amphibians that use this method during\u00a0the cold season.\u00a0\u00a0<\/p>\n
\u201cThey produce what\u00a0is sometimes called an antifreeze.\u00a0It’s\u00a0sort of\u00a0a\u00a0high\u00a0sugar content in their bloodstreams\u00a0…. They keep ice crystals from forming in their cells because that would be deadly, and\u00a0they’re\u00a0actually able\u00a0to almost create this sort of bubble of ice in their bodies around their important organs.\u201d\u00a0\u00a0<\/p>\n
Dr. Mooi added that the frogs usually tuck themselves into spots on the forest floor where they\u00a0won\u2019t\u00a0be disturbed by predators over the winter.\u00a0<\/p>\n
\u201cThen in the spring, when things warm up, they thaw out and go on their merry way,\u201d he said.\u00a0<\/p>\n
\u201cIt\u2019s a pretty amazing ability.\u201d\u00a0\u00a0<\/p>\n
Frogs: Taking cover beneath the frostline\u00a0<\/p>\n
For frogs that cannot freeze, the solution is to overwinter beneath the frost\u00a0line.\u00a0\u00a0\u00a0<\/p>\n
One strategy is to dive to the bottom of ponds and spend the winter there, slowing their metabolisms while relying on the remarkable ability to absorb oxygen through their skin.<\/p>\n
Dr. Mooi noted that while this approach works well,\u00a0frogs overwintering in ponds\u00a0are\u00a0at risk of winter kill, a phenomenon that occurs when oxygen levels in the water fall too low.\u00a0<\/p>\n
\u201cThese frogs\u00a0\u2014\u00a0and\u00a0fishes, for that matter\u00a0\u2014\u00a0will expire because they don’t have access to oxygen,\u201d he said.\u00a0\u00a0<\/p>\n
\u201cWhen the ice melts in the spring, sometimes you’ll see these animals floating along the shoreline or on the top of the water because they’ve run out of oxygen during the winter as they’re trying to avoid the freezing temperatures.\u201d\u00a0\u00a0<\/p>\n
<\/p>\n
Sometimes you might have ponds where\u00a0you’ll\u00a0see a winter kill with fish and\u00a0maybe some\u00a0frogs floating around after the winter, but\u00a0there’ll\u00a0be a painted turtle swimming happily around because\u00a0they’re\u00a0able to avoid that issue.<\/p>\n
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<\/p>\n
-Dr. Randy Mooi on how anerobic respiration helps turtles survive the harsh conditions of winter.<\/p>\n
<\/p>\n
The causes of winter kill can vary, but plants sometimes contribute to it.\u00a0\u00a0<\/p>\n
\u201cIn the\u00a0winter,\u00a0the plants,\u00a0for the most part,\u00a0are not\u00a0photosynthesizing,\u00a0and they may be just rotting and\u00a0using up\u00a0oxygen,\u201d he\u00a0explained.\u00a0<\/p>\n
\u201cAnd,\u00a0of\u00a0course,\u00a0there’s ice on the top of the pond, so\u00a0there’s\u00a0no access to the oxygen\u00a0that’s\u00a0in the atmosphere.\u201d\u00a0<\/p>\n
Toads,\u00a0salamanders, and snakes: Winter house guests\u00a0<\/p>\n
For\u00a0toads,\u00a0salamanders, and snakes, which must also get beneath the frost line, winter preparation sometimes means waiting out the cold temperatures as uninvited houseguests.\u00a0<\/p>\n
\u201cThey have to make sure that they don’t freeze at all, so …\u00a0toads usually burrow into the\u00a0sand,\u00a0or they might go into rodent burrows,\u201d\u00a0said\u00a0Dr. Mooi.\u00a0<\/p>\n
He added that some animals, such as snakes, also use loose soil from ant nests to avoid freezing.\u00a0<\/p>\n
Young snakes, in particular, will seek shelter from cold weather in the underground tunnels and chambers left by ants.\u00a0<\/p>\n
Turtles:\u00a0\u2018A very unusual ability\u2019\u00a0<\/p>\n
Manitoba\u2019s two turtle species, the western painted turtle and the snapping turtle,\u00a0also need to avoid freezing,\u00a0which drives them to the bottom of ponds, like their\u00a0amphibian\u00a0neighbours.\u00a0<\/p>\n
Their strategy for oxygen, however, is different \u2014 they\u00a0find a way to\u00a0avoid needing it.\u00a0<\/p>\n
\u201cThey can actually use what’s called anaerobic respiration, which is being able to\u00a0create energy to keep their bodies running through the winter without oxygen, a very unusual ability,\u201d said Dr. Mooi.\u00a0<\/p>\n
The curator noted that anaerobic respiration also occurs in humans during large energy expenditures, such as a long run or an intensive workout, resulting in lactic acid buildup that causes soreness.<\/p>\n
Related stories:<\/p>\n
Although the process is similar in turtles, there are several significant differences.\u00a0<\/p>\n
“When we feel the lactic acid burn,\u00a0we’re using a lot of energy all at once, but\u00a0during the winter,\u00a0turtles have really shut down their metabolism quite substantially, so they’re hardly using any energy at all,\u201d he said, adding that in winter, a turtle\u2019s heart rate can be as slow as beating once every five or even ten minutes.\u00a0\u00a0<\/p>\n
\u201cSo even if\u00a0they’re\u00a0using anaerobic respiration and creating lactic acid,\u00a0they’re\u00a0creating very,\u00a0very small amounts of it,\u201d he said.<\/p>\n
“They are able to use their shells and their bones as a buffer, so\u00a0they can neutralize that acid using the calcium\u00a0that’s\u00a0in\u00a0some\u00a0of their bones.\u201d\u00a0\u00a0<\/p>\n
He added that this process also helps turtles survive in ponds with low oxygen levels.\u00a0<\/p>\n
\u201cSometimes you might have ponds where\u00a0you’ll\u00a0see a winter kill with fish and\u00a0maybe some\u00a0frogs floating around after the winter, but\u00a0there’ll\u00a0be a painted turtle swimming happily around because\u00a0they’re\u00a0able to avoid that issue.\u201d\u00a0\u00a0<\/p>\n
Fish: The\u00a0sweet spot\u00a0of 4 \u00b0C\u00a0<\/p>\n
According to Dr. Mooi, fish also dive deeper during the cold season.\u00a0<\/p>\n
For aquatic animals, water temperature is\u00a0an important factor.\u00a0<\/p>\n
\u201cThe densest water is usually around four degrees Celsius, and so that sinks to the bottom and forces the other water upwards, so\u00a0colder water is actually near the surface,\u201d he\u00a0explained.\u00a0\u00a0<\/p>\n
\u201cThat’s\u00a0why some of these\u00a0fish go\u00a0down further,\u00a0because\u00a0they’ll\u00a0have a stable environment\u00a0in\u00a0that\u00a0[temperature].\u201d<\/p>\n
Frozen water at dawn.<\/p>\n
Dr. Mooi added that because oxygen levels can be lower near the bottom, fish often spend time around the middle of the water column.<\/p>\n
They may also find places to hide, such as rocky areas or logs,\u00a0because they also slow down for the winter and expend less energy.\u00a0\u00a0<\/p>\n
\u201cThat’s why,\u00a0generally,\u00a0when you’re ice fishing,\u00a0you’re not dragging the lure around,\u201d he explained.\u00a0\u00a0<\/p>\n
\u201c[Fishers]\u00a0are\u00a0just sitting\u00a0there with flags, … and\u00a0the fish will be attracted to those because they still eat,\u00a0but they need to go after something a little slower.\u201d\u00a0\u00a0<\/p>\n
A new life in winter\u00a0<\/p>\n
While some animals adapt to the winter, for others,\u00a0plummeting temperatures may even be\u00a0something to embrace rather than endure.\u00a0\u00a0<\/p>\n
Dr. Mooi said that\u00a0research\u00a0on\u00a0species such as lake trout (which tend to seek colder water even in summer)\u00a0indicates\u00a0that having more\u00a0cold water\u00a0to traverse in winter\u00a0alters the species.\u00a0<\/p>\n
\u201cThey end up moving from some of the deeper areas of the lakes that\u00a0maybe\u00a0don’t\u00a0have as much complicated environment into some of the shallower areas where there may be rocks and logs and things like that,\u201d he said.\u00a0\u00a0<\/p>\n
\u201cThere\u00a0have\u00a0been some studies that suggest their brains\u00a0actually increase\u00a0in size slightly in the winter.\u00a0The idea being that their brains are adapting to the kind of environment\u00a0they’re\u00a0in.\u201d\u00a0<\/p>\n
He added that certain organisms even require a cold spell to complete their life cycle, like turtles, for whom the sex of offspring\u00a0is affected by\u00a0temperature.\u00a0\u00a0<\/p>\n
\u201cWhen eggs are laid, there are certain temperatures that will produce males,\u00a0and\u00a0at\u00a0other temperatures,\u00a0the eggs will produce females or a mix of males and females,\u201d he said.\u00a0\u00a0<\/p>\n
The hidden wonder of winter<\/p>\n
For Dr. Mooi, looking at how amphibians, reptiles, and fish survive the winter highlights that beneath the\u00a0seemingly still\u00a0surface, the season is full of hidden activity.\u00a0<\/p>\n
\u201cWe think things are quiet and dead and that not much is happening, but in the animal world, there are quite a lot of things. Even though\u00a0they’re\u00a0slowing down,\u00a0there’s\u00a0a lot of things happening in their bodies\u00a0\u2014\u00a0and in their\u00a0behaviours\u00a0\u2014\u00a0that are\u00a0pretty important\u00a0for them to survive,\u201d he said.\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"During summer in the Pembina Valley,\u00a0amphibians\u00a0and\u00a0reptiles\u00a0are hard to miss.\u00a0 From\u00a0choruses of toads\u00a0and\u00a0slithering garter\u00a0snakes to painted turtles lined up…\n","protected":false},"author":2,"featured_media":355457,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[49,48,66,323],"class_list":["post-355456","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-ca","tag-canada","tag-science","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/355456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=355456"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/355456\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/355457"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=355456"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=355456"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=355456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}