An inexpensive and open-source method to study large terrestrial animal diet and behavior using time-lapse video and GPS

1. The behavior of free-ranging animals is difficult to study, especially on the large spatial and temporal scales relevant to long-lived large species. Animal-borne video and environmental data collection systems (AVEDs) record behavior and other data in real time as animals conduct daily activities. However, few studies have combined systematically collected, long term AVED foraging data with environmental and movement data to test hypotheses on animal foraging. Additionally, AVEDs are often either prohibitively expensive, or require extensive fabrication and programming knowledge. 2. The video and coordinate animal-mounted system (VACAMS) is an animal-mounted data collection system based on a modified GoPro® action camera platform that records short, first “person” perspective videos of animal behavior on an automated time-lapse schedule. As most videos are georeferenced, researchers can return to the locations of specific behaviors and collect accurate, fine-grained data on non-woody vegetation and other habitat characteristics that may influence animal behavior. Moreover, VACAMS are inexpensive and easy to use. 3. This study describes VACAMS preliminary data on cattle foraging and a hypothesis exploring free-ranging cattle browsing habits throughout the rainy season in the tropical dry forest of Sonora, Mexico. I generated a database of vegetation types consumed by cows each month (Annual, Woody, and Leaf litter) and compared actual vegetation type frequencies to a priori assumptions based on seasonal patterns of forage availability. During the monsoons, when palatable vegetation was abundant, frequencies of annual and woody perennial vegetation in cattle diets did not differ from month to month. When the rains ceased and palatable vegetation became scarce, cows switched to leaf litter, dead annual vegetation, twigs, and dried leguminous fruits. 4. Open source software and commercially available hardware make VACAMS financially attainable for many researchers, land managers, students, and other user groups. VACAMS could be used on a range of domestic and semi-domestic free-ranging animals, particularly in dense forests where conventional observations are impossible. With improvements to GPS battery life and durability, the weakest points of the system, VACAMS could also potentially apply to studies of other large terrestrial animals.

1. 自由漫游的野生动物的行为研究颇具难度，针对长寿大型物种开展的大空间尺度与长时程尺度研究更是如此。动物搭载式视频与环境数据采集系统（Animal-borne video and environmental data collection systems, AVEDs）可在动物开展日常活动时，实时记录其行为及其他相关数据。然而，目前鲜有研究将系统采集的长期AVED觅食数据与环境、运动数据相结合，以检验关于动物觅食行为的科学假说。此外，AVEDs往往要么成本过高难以承担，要么需要大量的设备制作与编程专业知识。
2. 视频与坐标式动物搭载系统（Video and coordinate animal-mounted system, VACAMS）是一款基于改装GoPro®运动相机平台的动物搭载式数据采集系统，可通过自动定时拍摄模式录制时长较短的动物行为第一人称视角视频。由于多数视频已完成地理配准，研究人员可返回特定行为发生的点位，精准采集非木本植被及其他可能影响动物行为的生境特征的细粒度数据。此外，VACAMS成本低廉且操作简便。
3. 本研究阐述了VACAMS在牛类觅食行为上的初步数据，以及一项针对墨西哥索诺拉州热带旱林雨季内散养牛类啃食习性的探索性假说。本研究构建了母牛每月采食的植被类型数据库（涵盖一年生植物、木本植物与枯落叶），并将实际植被类型采食频率与基于饲草可获得性季节模式提出的先验假设进行对比。在季风期，当适口性植被较为丰富时，牛类日粮中一年生与木本多年生植物的采食频率月度差异并不显著。而当降雨停止、适口性植被稀缺时，牛类会转而取食枯落叶、枯死一年生植物、细枝与干燥豆科果实。
4. 开源软件与商用现货硬件使得VACAMS的购置成本可为众多研究人员、土地管理者、学生及其他用户群体所承担。VACAMS可应用于多种家养与半家养自由漫游动物的研究，尤其适用于常规观测难以开展的茂密森林环境。作为系统当前的薄弱环节，若能改进GPS的续航能力与耐用性，VACAMS未来也可推广应用于其他大型陆生动物的相关研究。