The word "hyoid" refers to a small, u-shaped bone in the neck that is located just above the Adam's apple. It helps support the tongue and allows for swallowing and speech. Full definition
She her team found that howler monkeys face an anatomical trade - off: a species can either have a really big hyoid bone, or it can be very well endowed. (scientificamerican.com)
Those species with bigger hyoids live in single - male groups, so it makes sense to invest in what the researchers call «precopulatory traits,» that is, their courtship strategy of attracting the female's attention. (scientificamerican.com)
Males with bigger testes and smaller hyoids live in large groups with up to five or six males, and females mate with all males in the group. (sciencedaily.com)