Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii) in breeding and nonbreeding situations

During the winter and spring of 2000 and 2002, underwater calls of Weddell seals were recorded near Mawson. The goal was to determine if some call types were only given during the spring breeding season. The calls were classified into 10 broad types and the proportional usage of each was determined from May to December. All call types were present throughout the study period and during periods of darkness and light and at high, medium or low calling rates.

Taken from the abstract of the referenced paper:

Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii (Lesson, 1826)) near Mawson, Antarctica, investigated the hypothesis that certain call types function specifically in breeding behaviour. Recordings were collected at various sites in 2000 and 2002 from June to December. Twenty-four hour recordings were collected in 2002 at two sites. One hundred consecutive calls from each of 248 recordings were classified into one of ten common call types. Time to 100 calls provided the calling rate. The study period was divided into four periods representing initial sea-ice formation,
pre-pupping, pupping, and mating. Calling rate and light-dark differences were also examined. No presence-absence differences were observed for any of the call types with season. The largest difference between nonbreeding and breeding situations was an increase from 32.2% to 38.1% for descending whistles (F[3,244] = 4.483, p = 0.004). Trills gradually increased from 1.8% to 7.3% toward the mating period (F[3,244] = 30.932, p less than 0.001). The proportion of trills, chugs, descending whistles, and other call types also varied with calling rate and light-dark conditions. Some pre-reproductive behaviours may occur in winter, but no call types of Weddell seals function solely in the breeding season.

2000年与2002年的冬春时节，研究人员于南极莫森站（Mawson）附近记录了威德尔海豹（Weddell seal）的水下发声信号。本研究旨在探究是否存在部分叫声类型仅在春季繁殖季发出。研究将所有叫声划分为10个大类，并统计了5月至12月期间各类叫声的使用占比。结果显示，所有叫声类型在整个研究周期、明暗交替时段以及高、中、低不同发声率条件下均有出现。

本数据集取自相关研究论文的摘要：本研究以南极莫森站附近的威德尔海豹（学名：Leptonychotes weddellii (Lesson, 1826)）为研究对象，分析其水下叫声类型的占比，旨在验证"特定叫声类型仅服务于繁殖行为"这一科学假说。研究分别于2000年和2002年的6月至12月，在多个采样点位采集水下录音；2002年还在两个站点开展了24小时连续录音。研究人员从248份录音样本中各提取连续100个叫声，将其归类为10种常见叫声类型之一，并以采集满100个叫声所需的时长作为发声率的计算依据。本研究周期被划分为四个阶段：海冰初形成期、产仔前期、产仔期与交配期。同时分析了发声率与明暗周期的差异。结果显示，各类叫声类型的出现与否均未随季节产生显著差异。非繁殖期与繁殖期的最大差异为：下行哨声（descending whistles）的占比从32.2%提升至38.1%（F[3,244] = 4.483，p = 0.004）。颤音（Trills）的占比则随交配期临近从1.8%逐步升至7.3%（F[3,244] = 30.932，p < 0.001）。颤音、啭鸣（chugs）及其他叫声类型的占比亦随发声率和明暗条件发生变化。研究表明，部分繁殖前行为或可在冬季出现，但威德尔海豹并无仅在繁殖季专属使用的叫声类型。