Howler monkeys are a special favorite of mine, because they transform the forest with their songs. I'm thrilled to pieces to be able to give you video I made of them singing as they go to bed. But that's dessert. First, a bit about howlers.
The species native to the dry forest in the north Pacific coastal zone of Costa Rica is the mantled howler, named for the fringe of golden fur hanging off its flanks. There's also a black howler, and in the lowland tropical forest farther south is the beautiful red howler. I've seen all three species! but not all in Costa Rica. This is a particularly beautiful mantled howler, likely a female. Look at the individual vertebrae in the prehensile tail; many New World monkeys have those, while Old World monkeys don't. If I had a tail I'd want a prehensile one. It would be very handy when you had toddlers.
You can get a feel for that deep voice. More on how it's produced and a real howler concert in the next post!