Jurnal Biologi Tropis
Vol. 26 No. 3 (2026): in Progress

Predominantly Diurnal, Bimodal-Crepuscular Activity Patterns of Sun Bears (Helarctos malayanus) in Bukit Tiga Puluh National Park, Sumatera, Indonesia

Subagyo, Agus (Unknown)
Sinaga, Joshua (Unknown)
Dwi Kartika, Winda (Unknown)
Hisan, Muhammad (Unknown)



Article Info

Publish Date
29 Jul 2026

Abstract

The sun bear (Helarctos malayanus) is a vulnerable species listed on the IUCN Red List, whose behavioral ecology is critically shaped by habitat conditions. Increasing deforestation pressure in and around Bukit Tiga Puluh National Park (BTNP), Sumatra, highlights the urgency of understanding the spatiotemporal activity patterns of this species to support evidence-based conservation. This study analyzes the diel activity patterns of sun bears using secondary (bycatch) camera trap data collected by PKHS from 103 stations in BTNP between 2017 and 2022. From a total of 35,619 trap-days, 647 independent video detections were obtained. Kernel Density Estimation (KDE) analysis revealed a predominantly diurnal (62.44%) and strongly bimodal activity pattern. Activity peaks were recorded in the morning (06:00–09:00 WIB) and late afternoon (16:00–19:00 WIB), with a marked reduction during midday (11:00–14:00 WIB). This bimodal pattern indicates crepuscular characteristics, likely reflecting thermoregulatory adaptation and foraging strategies. The persistence of a strong diurnal signal suggests that BTNP continues to function as a relatively potential refuge from anthropogenic disturbance, although this inference is indirect, as human disturbance intensity was not measured directly. These findings provide a temporal basis for designing more effective anti-poaching patrol schedules and human–wildlife conflict mitigation strategies.

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Journal Info

Abbrev

JBT

Publisher

Subject

Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Immunology & microbiology

Description

Jurnal Biologi Tropis (ISSN Cetak 1411-9587 dan ISSN Online 2549-7863) diterbitkan mulai tahun 2000 dengan frekuensi 2 kali setahun oleh Program Studi Pendidikan Biologi PMIPA FKIP Universitas Mataram, berisi hasil penelitian dan ulasan Ilmiah dalam bidang Biologi ...