Inside the roaring sex lives of howler monkeys
Researcher dissects howler monkey roars
![red howler monkey](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/11/121215_howler_free.jpg?fit=860%2C460&ssl=1)
DEEP ROARS, SMALL SPERM STORES In nine species of howler monkey, researchers found an inverse relationship between testes size and size of the hyoid bone, part of the vocal tract.
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