Utilizing vocalizations to gain insight into the affective states of non-human mammals
This review discusses how welfare scientists can examine vocalizations to gain insight into the affective states of individual animals. In recent years, researchers working in professionally managed settings have recognized the value of monitoring the types, rates, and acoustic structures of calls, which may reflect various aspects of welfare. Fortunately, recent technological advances in the […]
The effect of anthropogenic noise on foraging and vigilance in zoo housed pied tamarins
The phenomenon of human-induced rapid environmental change (HIREC) is a great challenge in the modern world that presents a threat to all species. Research on the effect of anthropogenic noise on free-living wildlife is increasing but the effect of anthropogenic noise on the behaviour and welfare of captive wildlife has received limited attention, even though […]
Discrimination of Acoustic Stimuli and Maintenance of Graded Alarm Call Structure in Captive Meerkats
Animals living in human care for several generations face the risk of losing natural behaviors, which can lead to reduced animal welfare. The goal of this study is to demonstrate that meerkats (Suricata suricatta) living in zoos can assess potential danger and respond naturally based on acoustic signals only. This includes that the graded information […]
A System for Monitoring Acoustics to Supplement an Animal Welfare Plan for Bottlenose Dolphins
Animal sounds are commonly used by humans to infer information about their motivations and their health, yet, acoustic data is an underutilized welfare biomarker especially for aquatic animals. Here, we describe an acoustic monitoring system that is being implemented at the U.S. Navy Marine Mammal Program where dolphins live in groups in ocean enclosures in […]
Localize Animal Sound Events Reliably (LASER): A New Software for Sound Localization in Zoos
Locating a vocalizing animal can be useful in many fields of bioacoustics and behavioral research, and is often done in the wild, covering large areas. In zoos, however, the application of this method becomes particularly difficult, because, on the one hand, the animals are in a relatively small area and, on the other hand, reverberant […]
Frogs Call at a Higher Pitch in Traffic Noise
Male frogs call to attract females for mating and to defend territories from rival males. Female frogs of some species prefer lower-pitched calls, which indicate larger, more experienced males. Acoustic interference occurs when background noise reduces the active distance or the distance over which an acoustic signal can be detected. Birds are known to call […]
Learning to listen? Nestling response to heterospecific alarm calls
Many nestling birds go silent in response to parental alarm calls, potentially lowering their risk of being overheard by predators. Parents are not always nearby, however, and so offspring could also benefit if they respond to the alarm calls of other species. Response could be innate, particularly if heterospecific alarm calls are acoustically similar to […]
Eavesdropping on the neighbours: fledglings learn to respond to heterospecific alarm calls
Young birds and mammals suffer from a high risk of predation, and should be under strong selection for early response to cues indicating danger, including the alarm calls of other species. Despite this prediction, there has been little investigation of the development of response by young animals to heterospecific alarm calls, and none on fledgling […]
Postnatal Development of Echolocation Abilities in a Bottlenose Dolphin (Tursiops truncatus): Temporal Organization
In spite of all the information available on adult bottlenose dolphin (Tursiops truncatus) biosonar, the ontogeny of its echolocation abilities has been investigated very little. Earlier studies have reported that neonatal dolphins can produce both whistles and burst-pulsed sounds just after birth and that early-pulsed sounds are probably a precursor of echolocation click trains. The […]
Differences in alarm calls of juvenile and adult European ground squirrels (Spermophilus citellus): Findings on permanently marked animals from a semi-natural enclosure
The European ground squirrel (Spermophilus citellus) emits alarm calls that warn conspecifics of potential danger. Although it has been observed that inexperienced juveniles of this species emit alarm calls that sound similar to those of adults, studies focusing on juvenile alarm calls are lacking. We analyzed the acoustic structure of alarm calls emitted by six […]