also secrete blood (autohaemorrhage) from the mouth and nose. They may also perform an aggressive display in defence, hissing and striking without opening the mouth. They rarely bite in defense and lack venomous fangs. When caught they often regurgitate the contents of their stomachs. Grass snakes display a rare defensive behavior involving raising the front of the body and flattening the head and neck so that it resembles a cobra's hood, although the geographic ranges of grass snakes and of cobras overlap very little. However, the fossil record shows that the extinct European cobra Naja romani occurs in Miocene-aged strata of France, Germany, Austria, Romania, and Ukraine and thus overlapped with Natrix species including the extinct Natrix longivertebrata, suggesting that the grass snake's behavioral mimicry of cobras is a fossil behavior, although it may protect against predatory birds which migrate to Africa for the winter and encounter cobras there. Protection and threats The species has various predator species, including corvids, storks, owls and perhaps other birds of prey, foxes, and the domestic cat. In Denmark it is protected, as all five species of reptiles were protected in 1981. Two of the subspecies are considered critically endangered: N. n. cetti (Sardinian grass snake) and N. n. schweizeri. Mythology Baltic In the Baltic mythology, the grass snake (Lithuanian: žaltys, Latvian: zalktis) is seen as a sacred animal. It was frequently kept as a pet, living under a married couple's bed or in a special place near the hearth. Supposedly, snakes ate food given to them by hand. After the Christianization of Lithuania and Latvia, the grass snake still retained some mythological significance. In spite of the serpent's symbolic meaning as a symbol of evil in Christianity, in Latvia and Lithuania there were various folk beliefs, dating even to the late 19th century, that killing grass snakes might bring grave misfortune or that an injured snake will take revenge on the offender. The ancient Baltic belief of grass snakes as household spirits transformed into a belief that there is a snake (known or not to the inhabitants) living under every house; if it leaves, the house will burn down. Common Latvian folk sayings include "who kills a grass snake, kills his happiness" and "when the Saulė sees a dead grass snake, she cries for 9 days". Well-known literary works based on these traditions include Lithuanian folk tale Eglė the Queen of Serpents (Eglė