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:
Endangered_Species_Act

Context:
The Endangered Species Conservation Act (P. L. 91-135), passed in December, 1969, amended the original law to provide additional protection to species in danger of "worldwide extinction" by prohibiting their importation and subsequent sale in the United States. It expanded the Lacey Act's ban on interstate commerce to include mammals, reptiles, amphibians, mollusks and crustaceans. Reptiles were added mainly to reduce the rampant poaching of alligators and crocodiles. This law was the first time that invertebrates were included for protection.

Question:
When was the Endangered Species Conservation Act passed?

December, 1969