You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
London

Context:
Other mammals found in Greater London are hedgehogs, rats, mice, rabbit, shrew, vole, and squirrels, In wilder areas of Outer London, such as Epping Forest, a wide variety of mammals are found including hare, badger, field, bank and water vole, wood mouse, yellow-necked mouse, mole, shrew, and weasel, in addition to fox, squirrel and hedgehog. A dead otter was found at The Highway, in Wapping, about a mile from the Tower Bridge, which would suggest that they have begun to move back after being absent a hundred years from the city. Ten of England's eighteen species of bats have been recorded in Epping Forest: soprano, nathusius and common pipistrelles, noctule, serotine, barbastelle, daubenton's, brown Long-eared, natterer's and leisler's.

Question:
How many species of bats exist in England?

eighteen