After online research, Erica Fast found that the chance of finding a blue leopard frog is approximately one in a million.
While the number is difficult to determine definitively, all sources agree that what Fast found hopping across her backyard recently as she was mowing the lawn is a highly uncommon sight: a leopard frog with a unique blue hue.
Dr. Randy Mooi, the curator of zoology at the Manitoba Museum, said that leopard frogs, one of the more common species of frog in the province, normally appear in two “morphs” (a species’ distinctive form possibilities that include colour pattern) — golden brown, or bright green.
So how did Fast’s lawn visitor end up blue?
A natural wonder
According to Dr. Mooi, whose work concerning amphibians includes surveying endangered species in the province, the leopard frog’s rare appearance can be attributed to a “very rare mutation.”
“They're not able to create yellow pigment,” he said. “So, just like if you're painting a picture, amphibians will often mix blue and yellow pigment together to make green. When they're not able to make the yellow pigment, they will be blue.”
Dr. Mooi added that when amphibians lack this yellow pigment, the results can vary — the animals can take on various shades of blue or even present with dappled permutations of blue and green.
“It looks to me like there are different degrees of yellow productions,” said Dr. Mooi. “There may be some cells that are affected and some that are not, so that might explain how you're getting these different hues.”
An elusive phenomenon
Dr. Mooi said that while a blue leopard frog is certainly a rare sighting, to his knowledge, no large surveys have been done on its prevalence in the area.
He noted, however, that the same characteristic has been studied “a little further east” in North America with large populations of green frogs and bullfrogs.
“In green frogs, [the mutation] can be relatively common. It’s still rare, but it might be in .03% of the population or something like that,” said Dr. Mooi. “I think in leopard frogs it's much, much rarer.”
Dr. Mooi said that while he couldn’t find any written records of other blue leopard frogs in Manitoba, there have been rumours of the characteristic southwest of Winnipeg.
Other mutations
According to Dr. Mooi, Manitoba is also home to other less common frog mutations that alter the appearance of the amphibians.
True albinism — a complete lack of pigment that results in white skin and red eyes in frogs and other species — is another possibility.
“We're maybe a little bit fortunate here in Manitoba — we don't have to worry about any venomous or poisonous animals, so for the most part, you can usually get a good photograph and not have to worry too much about it.”
-Dr. Randy Mooi on capturing rare amphibians in photos.
He said that this spring, his colleague spotted an albino wood frog with dark eyes, which, although not a true albino, is an uncommon sighting nonetheless.
The instance will result in a report due to its rarity. To Dr. Mooi’s knowledge, the frog may be the first of its type recorded.
Frogs can also exhibit morphs that include a reddish hue or have mutations that involve missing limbs, a trait attributed to chemicals released into the environment.
Respecting unique occurrences
For those who do catch a glimpse of what could be a once-in-a-lifetime opportunity of spotting a mutation in nature, Dr. Mooi has a bit of advice.
Although he said that at one time, it was more common to capture the species, now with the ubiquity of high-quality cameras, he recommends doing what Fast did with the blue frog she spotted — after taking a photo, release the animal to carry on with its life.
“Our frog populations were hit quite hard by commercial enterprises for ... dissecting frogs in high schools. A good part [of that collecting] happened right here in Manitoba.”
-Dr. Randy Mooi on part of the reason amphibian populations in Manitoba are dwindling.
“You’re probably better off taking ... as good a photograph as you can. We're maybe a little bit fortunate here in Manitoba — we don't have to worry about any venomous or poisonous animals,” he said. “So for the most part, you can usually get a good photograph and not have to worry too much about it.”
Dr. Mooi added that there are applications that can help with the identification of the specimens, and, of course, sending pictures to local institutions with expertise is always welcome.
Fewer frogs, fewer opportunities to see mutations
Although there’s always a small chance of encountering a frog with mutations, today it might be even more difficult due to the dwindling populations of amphibians in the province.
The presence of the chytrid fungus, which causes an infectious disease that has impacted amphibians worldwide, is a factor that helps reduce numbers.
“I'm always really surprised because ... a lot of naturalists pay a lot of attention to what's around them, and it's amazing the things that you notice and see. I think you have a much higher appreciation for the diversity of our surroundings when you're paying a little bit more attention.”
-Dr. Randy Mooi on the value of taking an interest in one’s surroundings.
A web of human-led actions, including draining amphibians’ natural environments, wetlands, also contributes to population declines in the province, as did a business that boomed from the early 1970s to the early 1990s.
“A lot of people don’t remember [it] now, but there was a huge commercial frog industry here in Manitoba, and snakes, for that matter,” said Dr. Mooi.
“Our frog populations were hit quite hard by commercial enterprises for ... dissecting frogs in high schools. A good part [of that collecting] happened right here in Manitoba.”
Dr. Mooi said that there is a record of almost 50,000 kilograms of frogs collected for this purpose in the span of a single year, which is well over one million frogs.
“If you do that sort of thing over several seasons, you know you’re going to have some impact on the population,” he added, noting that because leopard frogs in particular mature in two to three years (in comparison to other annual species), it takes more time for the populations to replenish.
In Dr. Mooi’s view, to protect amphibians in the province for future generations, preserving the wetland habitat and reducing dependence on pesticides that impact the environment must be prioritized.
The beauty in looking
Despite the presence of barriers to seeing unique cases in nature, for Dr. Mooi, a sighting is always a possibility when one is as attentive to the environment as Fast was in her backyard.
Even if one does not see a blue frog, there are much more common sights that can evoke similar awe. Dr. Mooi’s experiences, which include fieldwork amidst his 21 years of curating the collections at the Manitoba Museum and conducting his own research, can attest to this.
“I'm always really surprised because ... a lot of naturalists pay a lot of attention to what's around them, and it's amazing the things that you notice and see,” he said. “I think you have a much higher appreciation for the diversity of our surroundings when you're paying a little bit more attention.”
Dr. Mooi added that the Pembina Valley, and Manitoba more broadly, is an environment that rewards those who take the time to appreciate it.
“We have some pretty interesting amphibians. If you go to the southwest part of the province, there are a couple of species there and, if you go at the right time, the air is just loud with their calls .... Some of these natural phenomena are just incredible to see or experience,” he said.
-With files from Connie Bailey.