Europeans have traditionally thought of beavers as fantastical animals due to their amphibious nature. They depicted them as looking dog-like with dagger-like tusks, fish tails and visible testicles. French cartographer Nicolas de Fer illustrated beavers building a dam at Niagara Falls; fantastically depicting them like human builders. Beavers have also appeared in literature such as in Dante Alighieri's "Divine Comedy" and in the writings of Athanasius Kircher, who wrote that when the beavers entered Noah's Ark they were given a stall near a water-filled tub which they shared with mermaids and otters.