In species with the largest vocal organs, males have the smallest testicles, suggesting an evolutionary trade-off between winning mates and making sperm
Source: Howler monkeys have to choose between big balls and big bawls | New Scientist
In species with the largest vocal organs, males have the smallest testicles, suggesting an evolutionary trade-off between winning mates and making sperm
Source: Howler monkeys have to choose between big balls and big bawls | New Scientist