Uploaded January 2022 | Updated September 2026, 2 weeks ago

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It's tough out there in the wild, especially for male howler monkeys. A new study suggests that these primates have to make a (evolutionary) choice: deep calls or small balls? Learn more about the research → livescience.com/52560-monkeys-with-deeper-calls-smaller-testes.html

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For the science geek in everyone, LiveScience.com breaks down the stories behind the most interesting news and photos on the Internet, while also digging up fascinating discoveries that hit on a broad range of fields, from dinosaurs and archaeology to wacky physics and astronomy to health and human history. If you want to learn something interesting every day, #LiveScience is the place for you. #HowlerMonkey #MonkeyBalls