Male monkeys go rouge for mating season
![snub-nosed monkey](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/12/121615_ht_monkey-lips_free.jpg?fit=860%2C460&ssl=1)
Male black-and-white snub-nosed monkeys have notoriously voluminous lips, and new research shows that in males that live and mate with groups of females, their lip color actually changes to a brighter red during mating season.
blickwinkel/Alamy