Howler monkeys sacrifice sperm for deeper roars
![a choir of howler monkeys](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/10/ticker_ht_acarayachorus_free.jpg?fit=860%2C460&ssl=1)
Researchers compared testes size with hyoid bone size in 10 species of howler monkey, including Alouatta caraya (shown).
Mariana Raño
Researchers compared testes size with hyoid bone size in 10 species of howler monkey, including Alouatta caraya (shown).
Mariana Raño