You will find this website useful for two reasons. First, it is a large list of animals including their genus/species (scientific) names to use in expanding your searches. Second, it is an excellent source for photographs.
This is a good source for government information on endangered species.
This is the National Oceanic and Atmospheric Administration’s (NOOA) page on marine life. Here you will find information such as the Endangered Species Act of 1973.
Here you will find much information on the World Wildlife Fund’s conservation efforts.
Provides conservation information on a number of plants and animals who are considered endangered.