The liver of certain animals — including the polar bear, seal, and husky — is unsafe to eat because it is extraordinarily high in vitamin A. This danger has long been known to the Inuit and has been recognized by Europeans since at least 1597 when Gerrit de Veer wrote in his diary that, while taking refuge in the winter in Nova Zemlya, he and his men became gravely ill after eating polar bear liver. In 1913, Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned, the latter fatally, from eating the liver of their sled dogs.
