Polar bears are the poster child of the Arctic, and under serious threat thanks climate change and the reduction of the polar ice caps. But one person’s loss is another one’s gain, and due to warming temperatures case grizzly bears are able to move further north as the icy conditions (and soft, blubbery seals – the preferred food source for polar bears) recede. This means that grizzlies and polar bears are more likely to come into contact with each other and (interestingly) are able to hybridise and produce a pizzly (or grolar) bear.
Interestingly, and unlike most hybrids, pizzly bears are quite robust (having traits of both parents mean they are likely able to exploit the habitats and food sources of both species) and able to produce viable offspring as shown in a study from 2017 that used genetic analysis to determine ancestry. They found some polar-grizzly hybrids to be 75:25 grizzly:polar bear, which means that one parent (in this case the mother) was a polar-grizzly hybrid to begin with.
As the likelihood of grizzlies and polars coming into contact with each other increases, we expect the number of hybrids in the population to increase as well. This won’t be the first time that these two species interbreed but it does still pose an interesting question of how we view ‘species’, as well as how we would approach hybrids in terms of conservation. Are we okay with polar-grizzly hybrids? Do we see them as a new species or simply an unwanted side effect of species range shifts? Do we view the northward-moving grizzlies as invasive?
Read more: Recent Hybridization between a Polar Bear and Grizzly Bears in the Canadian Arctic
Tanya Strydom is a PhD candidate at the Université de Montréal, mostly focusing on how we can use machine learning and artificial intelligence in ecology. Current research interests include (but are not limited to) predicting ecological networks, the role species traits and scale in ecological networks, general computer (and maths) geekiness, and a (seemingly) ever growing list of side projects. Tweets (sometimes related to actual science) can be found @TanyaS_08.
Red wolf and coyotes are an interesting conundrum when it comes to thinking of hybrids as ‘good or bad’. Thought to be a product of hybridisation between coyotes and grey wolves, red wolves have a lot of cultural significance in the southeastern United States. Native ranges of captive breeding programmes have worked at trying to re-introduce and establish red wolf populations in their historic ranges.
Yet these wolves have started having hybrid offspring with coyotes. This isn’t ideal, but because the red wolf population is so small, there isn’t a lot of genetic diversity among current red wolves. What if some ‘new’ genetic diversity can be found in wolf-coyote hybrids? There is a population of coyotes-not-coyotes in Galveston, Texas that have red wolf DNA – DNA that isn’t found in current red wolves! This ‘ghost’ DNA could be exactly what the doctor ordered when it comes to injecting some diversity back into the wolf population.
So if we were to breed (hybridise) the Galveston coyotes with red wolves we’d be introducing genetic diversity back into the population (yay!) but then also be making more hybrids, which… goes against what we would want – right? This is quite the tricky situation and has caused some head scratching when it comes to how best to approach this situation and really goes to show that we can’t be too black and white in our thinking.
The original research can be found here: Rediscovery of Red Wolf Ghost Alleles in a Canid Population Along the American Gulf Coast
Tanya Strydom is a PhD student at the Université de Montréal, mostly focusing on how we can use machine learning and artificial intelligence in ecology. Current research interests include (but are not limited to) predicting ecological networks, the role species traits and scale in ecological networks, general computer (and maths) geekiness, and a (seemingly) ever growing list of side projects. Tweets (sometimes related to actual science) can be found @TanyaS_08.
Image Credit: Carol M. Highsmith, CC BY 2.0, Image Cropped
The ultimate goal of species conservation is to preserve a species’ existence in the natural world. To effectively do this, we must know the extent of “species” that we want to conserve. That may sound simple, but the concept of hybridisation can blur the lines of where one species begins and another ends beyond recognition.