10. Roughly 172,000 narwhals are swimming in the Arctic today.
A narwhal is a toothed whale and is closely related to dolphins, porpoises, and orcas. They live and travel in pods that range in size from a few narwhals to several hundred individuals, but the congregations can be in the thousands in the summertime. Females, young, and immature males live together, and adult males live in their own pods. They have a famous tusk that is actually a specialized tooth that protrudes out of the left lip, and in rare cases, a narwhal can have two.
While all males have tusks, only 15 percent of females have a tusk. The longest tusks can reach over eight feet long. Understanding the function of the tusk is an ongoing area of investigation. One of the narwhal’s unique talents is diving. They are some of the deepest diving whales, with a record dive of over a mile deep! They are also excellent at conserving oxygen as their muscles are built to minimize oxygen use and simultaneously carry large amounts of oxygen. Interestingly, during the deepest dives, a narwhal can shut off oxygen flow to unessential organs and instead divert it to where it is needed most.