Monkey on a heart-rending notify their little eggs – commander

The relationship between the volume of monkeys roar -revunov and the size of their testicles have set the British scientists. It turned out that the most vociferous male howler – the smallest testicles.

«It is possible that the contribution of resources in the development of a powerful roar and related bodies during the growth of baby leaves no energy for the development of the labia bodies. On the other hand, it may be true that a powerful bond and sip as efficiently distilled off other males and attracts females that their owners do not need to acquire a large testicles “- said Jacob Dunn of Cambridge University (UK).

howler monkeys – primates average size, their weight is only 6.7 kilograms. A distinctive feature is the extremely loud, deep growl. This roar is useless in terms of survival, but it helps to extend his male gender. Charles Darwin once considered howler monkeys a clear example of the evolution of sex in animals. Jacob Dunn agreed with his colleagues to test this hypothesis the founder of the theory of evolution, which was organized by the observation of the behavior of nine species of howler, the study of the structure of their body.

In the course of observations, scientists have noticed that the males – the owners of the most profound and formidable roar, we had a relatively small testicles. After examining the structure of their vocal cords, larynx and other parts of the body, the researchers found that the size of the testicles, and even then, public groups live howler, it all depended on how large was the hyoid bone. If this bone was small, the testicles in males were large enough that allows them to live in large flocks howler with several males. Contrary to these individuals, males with a large hyoid bone, lived in the company of a small “harem” of several females.

This bone is a “cavity”, reinforcing the roar of the male. The formation of this bone requires large resources, which may influence the formation of relatively small genitals.

Currently, Dunn and his colleagues are studying the shape of the bones in different kinds of howlers. But scientists believe that in any case, Darwin was right – the roar of howler really is a consequence of the sexual evolution that made different kinds of monkeys to choose the opposite strategy of the struggle for the attention of females.

Comparing animals, Jake Dunn and his team found that different kinds of howlers, it seems, are looking for a compromise between the development of powerful vocal tract needed to play lower and impressive music, or the development of large testicles – for more sperm.

According to him, depending on the conditions in the group pairing different primates choose which of these signs develop. Jake Dunn explains that some animals – such as walruses, seals and sea lions – especially large sizes have smaller genitalia.

In 2012, it was even published study suggests that a man with a deep voice are less sperm left.

But the results of the study are howlers first recorded example of a compromise between the vocal and production of all kinds of sperm. “It was a surprise – to find out that such trade-offs may be more common than previously thought,” – said Jake Dunn.

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