Howler monkeys may owe their color vision to leaf hue
Distinguishing red from green makes healthier leaves stand out
![howler monkey](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/02/022117_lh_howlermonkey_main_free.jpg?fit=860%2C460&ssl=1)
MONKEY BUSINESS Being able to tell red and green apart helps howler monkeys like this one pick out younger, more nutritious leaves, research suggests.
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