Wednesday, July 17, 2019

Narwhal Populations Are Thriving Despite Lack of Genetic Diversity

In the scientific community it has long been thought that in order to be a fit and thriving population, you need to have high genetic diversity within that population. In the case of the narwhal- a two ton porpoise known for the 8 foot tooth that grows out of its upper lip- their population has very low genetic diversity. This would normally correlate to a species that is close to extinction. To researchers surprise they found that the narwhal populations are thriving with numbers in the hundreds of thousands.

“There’s this notion that in order to survive and be resilient to changes, you need to have high genetic diversity, but then you have this species that for the past million years has had low genetic diversity and it’s still around — and is actually relatively abundant,” Eline Lorenzen, a molecular ecologist and curator at the Natural History Museum of Denmark, who led the new research, said in a statement.

The reason it is thought that high genetic diversity makes a population less vulnerable to extinction is because having a larger pool of genes to choose from makes it easier to evolve in repose to changes in a populations environment. Researchers estimate that the global population of narwhals is 170,000, enough to move the narwhals from the status of "near threatened" to "least concern," which means they are doing just fine. 

Although this discovery shows that narwhal population sizes are great despite the odds, it does not guarantee that they will be able to adapt to the rapid climate change that is taking place in the arctic, the only place that narwhals live. Temperatures on this planet are rising and ice is melting. In the near future narwhals will be challenged and their low genetic diversity that has sustained them for hundreds of thousands of years may not be enough to endure the changes that have been occurring.


  1. Narwhals are definitely in my top five favorite animals list because they are the unicorns of the sea! My interest in dentistry also contributes to my love for narwhals because the "horn" is actually a tooth. The fact that narwhals are thriving despite low genetic diversity is fascinating because we are always taught that a high genetic diversity is necessary for a species to thrive. For a species that is unique for its long tooth, I am glad they are thriving! However, like you said, a low genetic diversity may be trouble due to rapid climate change. The reason why melting icecaps are a problem is because they are freshwater, and whales primarily live in saltwater. Beluga whales, a close relative of narwhals can transition in and out of different waters, but there's no guarantee this can happen with narwhals.

  2. While I was reading the article and how "narwhals are thriving" I immediately though about how the climate change with effect them. I wonder if they can adapt to drastic changes or if we will start to see a decrease in the population in the near future. Also, it is interesting how populations who thrive typically have a higher genetic diversity. With the case of the narwhal, I wonder how other species with low genetic diversity are affected or how quickly they face being threatened in terms of population.

  3. I feel like that no matter how many narwhals on Earth they will always be "nearly extinct" because they are always one small event away from becoming extinct. As you said genetic variation allows for a species to thrive because there a large variety of genes in the gene pool and odds are some will be advantageous in a given situation. If their environment was to quickly change, the narwhal species would likely go extinct because they are all too similar genetically speaking.

  4. It makes me happy to learn that the narwhals are doing okay despite the low genetic diversity. Most species thrive less when their diversity is low. However, the narwhals may have just gotten lucky with a very static environment. As Dan said, this makes them at high risk of extinction from any small event. Climate change is a risk factor for most species. However, the species that are most at risk are those that will be least able to adapt to rising temperatures. With a low genetic diversity, the outlook for the narwhals does not look good. However, they have already surprised us this far.