The groan says it all -- dominant male deer have the deepest calls

Sep 08, 2008

(PhysOrg.com) -- The low timbre and enticing vibrations of a deep voice have long been considered a key element of male attractiveness. Now it seems that it's not just human females that appreciate a husky vocalisation.

Research published this month in PLoS One, an online scientific journal, has shown that female fallow deer are attracted to a deep call. Data taken from a deer herd in Phoenix Park, Dublin indicate that the males with high dominance status also have the deepest 'groans' (the name of the fallow deer call). These males are also more successful when it comes to getting matings.

Males can groan up to 60 times a minute during the 'rut' — the deer mating season, which falls in October. This can increase up to 90 times a minute immediately after mating.

The deer's groan is directly related to body size. Deer share a vocal trait with humans — the descended larynx — which increases the length of their vocal tract and allows the groan to deepen. As the groan travels from the animal's vocal chords, through its throat and out of its mouth, it is uniquely modulated to create formant frequencies. It is these frequencies that indicate body size. In fact, the descended (and also mobile in the case of deer) larynx makes the animal sound bigger than he actually is, suggesting that false advertising in the search for a mate isn't an exclusively human trait. The frequencies produced by the vibrations of the vocal chords are closely linked to the dominance status of the animals.

It was thought that the descent of the larynx was a pre-cursor to the evolution of human speech, by allowing greater freedom of movement of the tongue. For example, chimps and other primates have a larynx that is situated quite high up in the neck. However, recent research suggests that the descent of the larynx is more likely linked to size exaggeration, as is the case with deer.

The research gives us an insight into the evolution of vocal communication in a mammal, which also has implications for early human vocal development,” said Dr Alan McElligott, biologist at The University of Nottingham, who has been studying the behaviour and biology of fallow deer since 1992.

The research also found that the deer with the deepest groans were also superior fighters in the herd — even though they may not be the largest in terms of body size.

“Fallow deer are extremely vocal,” Dr McElligott added. “During the rut the dominant males groan once a second and there are very high levels of competition between them. Only a few males will gain most mating in any rut; most males never get any!” The sounds they make as they fight and mate are key features of this aggressive, competitive behaviour.

“The groans indicate to the females the 'quality' of their potential mate — this could have evolved due to the high levels of competition between males.”

Dr McElligott and his colleagues recorded the groans and measured the size of the dominant males in the Phoenix Park herd over six years. The study focussed on 17 different dominant males, measuring their mating success. It proved for the first time that a mammal species other than primates use their call to signal social dominance.

Dominance is key for males in a fallow deer herd. Usually, it is only the top five or six males in a herd who mate during the rut, with the weaker males often seeing no action at all. The dominant males don't have it easy though — they don't eat during the rut and can lose 25 per cent of their body weight. Males may mate many times in a day — one deer the team were studying managed 22 times in 11 hours. The vast majority of females typically mate just the once.

Provided by University of Nottingham

Explore further: Population genomics unveil seahorse domain

add to favorites email to friend print save as pdf

Related Stories

Baleen whales hear through their bones

17 minutes ago

Understanding how baleen whales hear has posed a great mystery to marine mammal researchers. New research by San Diego State University biologist Ted W. Cranford and University of California, San Diego engineer ...

Researchers determine key element in circadian clock speed

18 minutes ago

In a discovery that may lead to new treatments for sleep disorders, jet lag and other health problems tied to circadian rhythms, researchers at Dartmouth's Geisel School of Medicine have identified a determinant ...

Global warming won't mean more stormy weather

18 minutes ago

A study led by atmospheric physicists at the University of Toronto finds that global warming will not lead to an overall increasingly stormy atmosphere, a topic debated by scientists for decades. Instead, ...

Recommended for you

Population genomics unveil seahorse domain

2 hours ago

In a finding vital to effective species management, a team including City College of New York biologists has determined that the lined seahorse (Hippocampus erectus) is more a permanent resident of the we ...

Researchers develop new potato cultivar

5 hours ago

Dakota Ruby is the name of a new potato cultivar developed by the NDSU potato breeding project and released by the North Dakota Agricultural Experiment Station. Dakota Ruby has bright red skin, stores well and is intended ...

Researchers develop new soybean variety

5 hours ago

The North Dakota Agricultural Experiment Station has developed and released ND Henson, a conventional soybean variety, according to Rich Horsley, chair of the NDSU Department of Plant Sciences.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.