Acoustic Battles for the Harem: How the Calls of Siberian Wapiti Reveal Their Status and Individuality
Researchers at HSE University, Lomonosov Moscow State University, and the A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences have studied the distinctive vocalisations of Siberian wapiti (Cervus canadensis sibiricus) stags during the peak of the mating season, when males produce rutting calls (bugles) to attract females (hinds) and deter rivals. The scientists have discovered how the acoustic parameters of these rutting calls reflect the stag's status—whether he currently holds a harem or is still attempting to acquire one—as well as his individual characteristics. The study has been published in Journal of Zoology.
Rutting calls are a vital component of intra-species interactions in Siberian wapiti, enabling stags to attract female hinds (sometimes entire groups) and intimidate rival males. These calls are integral to the mating season. In the wild, competition for keeping a harem (a group of females) is intense, prompting male ungulates to develop sophisticated strategies that combine physical displays and vocal demonstrations of strength. Acoustic displays are highly effective because they carry over long distances and remain reliable even in low-visibility conditions, such as at night, when deer engage in most of their interactions. Rutting calls enable females to assess a male's status and quality from a distance, while also signalling to rivals whether it is worth challenging him in a fight.
The study findings suggest that rutting calls act as a kind of 'passport,' reflecting the stag's harem-holding status. Compared to peripheral stags that remain outside a harem, harem holders produce shorter rutting calls with a higher minimum fundamental frequency.
The fundamental frequency of sound is a parameter that is subjectively perceived as the pitch of a voice and includes various measurements, such as the minimum, maximum, initial, and final fundamental frequencies. Moreover, even in a single stag, a change in status leads to alterations in the parameters of his rutting calls: when he acquires a harem, the initial and maximum fundamental frequencies of his calls decrease, while the minimum fundamental frequency increases, and the calls become shorter.
Although rutting calls can reflect a male's status and change as it evolves, their individual acoustic parameters typically remain consistent. It was previously believed that each stag has unique acoustic characteristics, a kind of vocal signature, allowing it to be distinguished from other stags. This presumed vocal individualisation is still used in nature reserves to monitor the number of stags by ear. In this method, a trained observer, stationed at a specific point, identifies the number of male deer nearby based on the differences in their voices.
According to Olga Sibiryakova, Associate Professor at the HSE Faculty of Biology and Biotechnology and co-author of the study, although individuality is encoded in rutting calls, it does not always manifest clearly enough: zoologists were able to correctly identify the individual stags in 53.2% of calls, which exceeds random chance but indicates that it is not always possible to identify a specific animal. It is noteworthy that discriminant analysis correctly classified 78.9% of bugles according to the stag's status.
'The vocalisations can convey information not only about the individual caller but also about his status, and status information is conveyed much more clearly in the sounds than individuality, which suggests that transmitting status information to others is of greater importance during the mating period,' the researcher notes.
The study findings can be applied to managing deer herds in natural environments, tracking these animals for conservation and hunting purposes, and developing non-invasive methods for studying ungulates. The use of non-invasive monitoring methods can facilitate the work of zoologists and ecologists by allowing them to track the status and behaviour of deer in various conditions without disrupting their natural habitat.
See also:
Biologists Discover Unique Properties of MiR-93-5p MicroRNA in Prostate Cancer
Researchers at the International Laboratory of Microphysiological Systems of the HSE Faculty of Biology and Biotechnology investigated how different isoforms of the same microRNA influence gene function in prostate adenocarcinoma. The study found that in some cases, microRNAs can reinforce each other’s effects by targeting and suppressing the same genes. This finding offers a fresh perspective on the molecular mechanisms underlying tumour development and on the search for disease biomarkers. The results have been published in PeerJ.
HSE Economists Use Search Queries to Forecast Birth Rates
Researchers from the HSE Faculty of Economic Sciences have shown that the accuracy of birth rate forecasts for Russia can be improved by almost 50% by incorporating the dynamics of online search queries related to pregnancy and childbirth into forecasting models. In the best-performing models, the forecasting error fell from 4.6% to 3.2%. The findings have been published in Populations and Economics.
When Looking at Their Own Faces, Men Forget Everything
In an experiment involving 15 healthy men, scientists at HSE University investigated how different phases of the cardiac cycle influence the excitability of the motor cortex when participants viewed either their own photograph or the faces of strangers. The researchers found that when participants looked at their own image, the brain’s response to signals from the heart was weaker, meaning that the influence of cardiac activity on the motor cortex decreased. This finding came contrary to expectations, as self-focused attention was thought to enhance the brain's sensitivity to internal bodily signals. The study has been published in Frontiers in Signal Processing.
HSE Researchers Discover Who Eats Out in Russia—And Why
Around one-third of Russians (31.3%) rarely eat out or buy ready-made meals. The core group of active consumers—those who eat out or purchase prepared food almost every day or several times a week—accounts for only about 9% of the population. These are the findings of a study conducted by the HSE Institute for Social Policy. According to the researchers eating out is no longer a marker of high social status in Russia.
Scientists Model How Interactions Between Societies Can Trigger Chaotic Behaviour
Scientists at HSE MIEM have proposed a mathematical model explaining how interactions between societies can influence their stability. Based on the classical theory of evolutionary games, the study reveals an unexpected effect: even a weak informational influence of one society on another can cause one society to remain stable while the other exhibits chaotic behaviour among its individual members. The study has been published in the International Journal of Bifurcation and Chaos.
Ancient Craniiform Brachiopod: A Newly Discovered Species with a Unique Shell Shape and Lifestyle
Scientists from HSE University, MSU, and Tallinn University of Technology have studied a fossil species of ancient brachiopods that lived in a warm sea in what is now northern Estonia more than 445 million years ago. These ancient brachiopods developed a cup-shaped shell with a protective 'cap' that shielded them from overgrowth by other marine organisms. The study has been published in Palaeogeography, Palaeoclimatology, Palaeoecology.
Scientists Develop Bacterium-Sized Microlaser
An international team of researchers, including scientists from HSE University–St Petersburg, has developed microlasers that emit deep-ultraviolet light at a wavelength of 255 nanometres. The devices operate at room temperature, and the smallest of them measures just two micrometres in diameter—roughly the size of a bacterium. These microlasers could be used in sensors, spectroscopic systems, photonic chips, and communication devices. The paper has been published in Optics & Laser Technology.
HSE Develops App for Assessing Phonological Processing in Children
Researchers at the HSE Centre for Language and Brain have developed a new digital tool for assessing children's phonological processing skills—the ZARYA (Sound Analysis of the Russian Language) test battery. It is the first standardised application in Russia designed to provide a fast and reliable assessment of children's ability to distinguish speech sounds, retain them in working memory, and perform phonemic analysis. The app runs on Android tablets and smartphones and is available for download from RuStore. Details of the test validation have been published in the Journal of Speech, Language, and Hearing Research.
Researchers Discover How Spelling Errors Slow Down Reading in Russian
Psycholinguists from the Centre for Language and Brain at HSE University–St Petersburg have shown that words that are frequently misspelled are processed more slowly by readers, even when presented with the correct spelling. The researchers confirmed this effect for the first time using Russian-language materials and found that response speed is most strongly linked to how confidently individuals can distinguish the correct spelling of a word from an incorrect one. The study has been published in The Mental Lexicon.
Scientists Discover Why Europium 'Misbehaves'
Europium is a rare-earth metal responsible for the pure red glow in displays and other luminescent materials. For a long time, however, it refused to emit light when surrounded by certain organic molecules known as acylpyrazolone ligands. Chemists have now uncovered the reason: in europium complexes with these ligands, a 'black window' appears—a charge-transfer state in which the energy absorbed by the ligand is dissipated as heat rather than emitted as light. Understanding this mechanism opens the way to designing more efficient red-emitting materials for displays, fluorescent thermometers, and chemical sensors. The results have been published in Dalton Transactions.