[Column] Expansion of bear damage and impact of sound

Column en Bear Sound
[Column] Expansion of bear damage and impact of sound

1. Introduction: Current status of bear damage and the importance of sound

Text: mmr Theme: An analysis of the damage caused by bears, which has been increasing in recent years, from the perspective of the impact of noise and behavior control. Examining the role of sound design in the coexistence of humans and bears

In recent years, damage caused by bears has been rapidly increasing in Japan. There are approximately 1,000 cases of crop damage per year, and human damage has approximately doubled in the past 10 years (Ministry of the Environment’s ““Wild Animal Damage Statistics 2024’’). The physical measures taken so far are not sufficient, and sustainable damage control methods are required.

What is attracting attention is the ““control of bear behavior through sound.’’ Bears have a well-developed sense of hearing and are sensitive to human voices, warning sounds, and artificial sounds at specific frequencies. In recent years, an increasing number of demonstration experiments have been conducted by farmers, local governments, and research institutions, expanding the possibilities of sound management based on scientific evidence.

2. Ecology and behavioral characteristics of bears

2.1 Main bear species and distribution

  • Asia black bear (Ursus thibetanus): Found in Honshu, Shikoku, and Kyushu, body length 120–150 cm, good at arboreal behavior, omnivorous.
  • Brown bear (Ursus arctos yesoensis): Hokkaido, 180–250 cm long, large, also consumes fish and small animals.

Both species are nocturnal, but daytime activity can also be seen during the spring and fall hunting seasons.

2.2 Hearing characteristics and response to sound

  • Hearing frequency band: 200Hz–10kHz
  • Can respond to human voice (250–4000Hz)
  • Sensitive to thunder and warning sounds (1000–8000Hz)
  • Low and high frequency sounds in nature also influence behavior

Hearing characteristics of bears

graph TD A["Frequency band"] --> B["Human voice: 250–4000Hz"] A --> C["Warning sound: 1000–8000Hz"] A --> D["Natural Sounds: Low Frequency to High Frequency"]

3. Background to the spread of damage

3.1 Population decline and abandonment of satoyama

Due to depopulation, agricultural land in mountainous areas has been left abandoned, and bears’ habitat has moved closer to human settlements. In Hokkaido, the area of ​​abandoned farmland has increased by approximately 30% from 2000 to 2020, which is correlated with an increase in bear encounters (Hokkaido University Wildlife Research Report 2023).

3.2 Proximity of agricultural crops and forest resources

With the increase in orchards and nut forests, there are more cases of bears invading communities. A survey of orchards in Nagano Prefecture found that in some areas, the annual damage rate reached approximately 12%.

3.3 Impact of climate change

Due to the decrease in snowfall and fluctuations in fruit growth in early spring, they are more likely to visit human settlements during periods of food shortage.

3.4 Damage statistics by region (2020–2024)

Region Annual number of damage Crop damage rate Number of human damage
Hokkaido 320 10% 5
Nagano Prefecture 150 12% 2
Tohoku 180 8% 3
Kyushu 90 6% 1

4. Effect of sound on bears

4.1 Sound types and reactions

  • Whistle: Light evasive action

  • Human Voice: Medium Evasion

  • Firecracker: Strong Evasion

  • High-frequency electronic sound (8–10kHz): Experimental avoidance and prevention of habituation are issues

Sound type and bear reaction strength

graph LR A[whistle] --> B[light evasion] C[human voice] --> D[Moderate avoidance] E[firecrackers] --> F[strong evasion] G[high frequency electronic sound] --> H[experimental avoidance]

4.2 Experimental example

  • Hokkaido Orchard (2015–2018): Invasion rate reduced by 40% due to use of firecrackers

  • Kyushu electronic sound trial (2019–2021): Short-term avoidance due to the use of high-frequency equipment, long-term habituation occurs

  • Tohoku AI Speaker Demonstration (2020–2023): Success rate of bear intrusion warning 65%

5. Coexistence strategy between human activities and sound

5.1 Sensor-linked warning sound

Automatically generates a sound when a bear approaches. Encourage avoidance actions before damage occurs.

5.2 Regular patrol sound

A sound device that alerts people to the presence of humans reduces their desire to invade.

5.3 Urban and suburban applications

It has already been introduced in Nagano Prefecture and Hokkaido. Safety is ensured by using human voice and electronic sounds during night patrols.

6. The future of sound design

6.1 AI/drone technology

Sound generation according to behavioral patterns using AI analysis. Cover a wide area with drone patrols.

6.2 International cases

  • California, USA: Intrusion prevention using electronic sounds and human voice

  • BC, Canada: Non-lethal acoustic management reduces crop damage

7. Discussion: Redefining the relationship between humans and bears

Damage control is a matter of coexistence, not pest extermination.

Sound countermeasures are non-lethal and effective

  • Challenges: Habituation, ecosystem impact, cost

8. Conclusion

The increasing damage caused by bears is not just a problem for wild animals, but also a mirror of structural changes in human society. Distortions in the environment that we ourselves have created, such as depopulation, climate change, and unbalanced forest use, are driving bears out of the mountains and into villages. In this reality, damage control through sound is extremely suggestive as ““a medium for redesigning the relationship between humans and animals.’’ Sound is non-lethal and can adjust behavior through fear and learning. In other words, it is control through “resonance” rather than violence, and it can be an ethically sustainable option.

The challenge for the future is to evolve it into an ““acoustic landscape design” that incorporates local environmental sounds and the sounds of human life, rather than just a threatening sound. When the behavioral patterns of bears learned by AI are combined with the local sound culture and seasonal rhythms, sound will go beyond a warning and become an ““interface for coexistence.” Sound policy that combines scientific knowledge and cultural sensitivity is the key to shaping the future of humans and the wild. Communicating with sound, maintaining distance, and restoring harmony to the entire biosphere—this can be called the next era’s “environmental ethics of sound.”

Case studies of damage control using sound (2000–2025)

timeline title サウンド活用事例 2002 : 北海道農家が笛・爆竹試験 2010 : AIスピーカー試験導入（東北） 2015 : 高周波電子音トライアル（九州） 2020 : ドローン音響巡回システム導入（北海道） 2025 : 全国自治体で実証実験拡大

Sound usage flow for bear damage control

flowchart TD A[Monitoring of farmland and villages] --> B[sensor detection] B --> C[Acoustic warning transmission] C --> D[bear escape behavior] D --> E[Mitigating damage and ensuring safety]

References/Materials

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