What is real? Recognizing hoaxes on the internet

The internet is full of sites with misinformation or just plain hoaxes. Can you tell which of the following websites are about a real subject and which are made up?
Be sure to check the authors of the website, the type of extension (.com, .org, etc.), how recently it was updated, and whether the information can be verified.
To verify the information, use a search engine to look up another website or check World Book Student and compare facts to see if they match.

World Wildlife Fund Tree Kangaroo
http://www.worldwildlife.org/species/finder/tree-kangaroos/tree-kangaroos.html

Save the Endangered Pacific Northwest Tree Octopus
http://zapatopi.net/treeoctopus/

Animal Corner Gharials
http://www.animalcorner.co.uk/reptiles/rep_gharial.html

Dihydrogen Monoxide
http://www.dhmo.org/