I thought this looked like an interesting animal. An indri is the largest species of lemur living today. Madagascar is the only place where they are found in the wild. They spend most of their time in the trees.
They are very sociable animals so you won't find them living alone. The family unit is made up of a male, female and young with the female being the dominant one. This means they get to eat first while the male defends the territory.
A distinctive feature of the indri is their loud, long songs which last anywhere from 45 seconds all the way up to 3 minutes. They will sing every day, sometimes seven times a day.
The song begins with a roar in which the whole family participates. Then the parents follow that up with several notes lasting up to 5 seconds each. Finally they wail starting at a higher tone then descending as their pitch becomes lower and lower.
Their songs are used to communicate with other families, to indicate danger or other disturbances. They usually head up to the treetops before they sing which allows them to be heard at farther distances. Most songs are sung in the morning hours.