Tusks
Elephants
The African elephant is the biggest animal on land.
Its tusk is a tooth. It is the biggest tooth of any living animal.
They use their tusks for digging for water when it is dry. They also strip bark off trees. They eat the bark!
Photo by Yathin S Krishnappa. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
Walrus
Walruses live in the Arctic Ocean.
A walrus uses its tusks to climb onto ice.
It also uses its tusks to make holes in ice. When it is swimming, it must break floating ice to breathe air out of the water. A walrus is a mammal. It has lungs just like us, so it cannot breathe underwater.
Narwhal (say nar-wall)
The narwhal is a sort of whale. A male narwhal has a long, straight tusk. Females sometimes grow a short tusk. They are called the 'unicorns of the sea'.
Credit: NOAA/OAR/OER. Photographer is Dr. Kristin Laidre, Polar Science Center, UW. Photo is in the public domain on NOAA.
We do not know what a narwhal uses its tusk for.
Like walruses, narwhals live in the Arctic Ocean.